Tuesday, October 16, 2018

The Smell of Fear

A repost of an original article from October 24, 2012.

Several animals, many of them insects, crustaceans and fish, can smell when their fellow peers are scared. A kind of superpower for superwimps, this is an especially useful ability for prey species. An animal that can smell that its neighbor is scared is more likely to be able to avoid predators it hasn’t detected yet.

Who can smell when you're scared? Photo provided by Freedigitalphotos.net.

“What does fear smell like?” you ask. Pee, of course.

I mean, that has to be the answer, right? It only makes sense that the smell of someone who has had the piss scared out of them is, well… piss. But do animals use that as a cue that a predator may be lurking?

Canadian researchers Grant Brown, Christopher Jackson, Patrick Malka, Élisa Jaques, and Marc-Andre Couturier at Concordia University set out to test whether prey fish species use urea, a component of fish pee, as a warning signal.

A convict cichlid in wide-eyed
terror... Okay, fine. They're
always wide-eyed. Photo by
Dean Pemberton at Wikimedia.

First, the researchers tested the responses of convict cichlids and rainbow trout, two freshwater prey fish species, to water from tanks of fish that had been spooked by a fake predator model and to water from tanks of fish that were calm and relaxed. They found that when these fish were exposed to water from spooked fish, they behaved as if they were spooked too (they stopped feeding and moving). But when they were exposed to water from relaxed fish, they fed and moved around normally. Something in the water that the spooked fish were in was making the new fish act scared!

To find out if the fish may be responding to urea, they put one of three different concentrations of urea or just plain water into the tanks of cichlids and trout. The cichlids responded to all three doses of urea, but not the plain water, with a fear response (they stopped feeding and moving again). The trout acted fearfully when the two highest doses of urea, but not the lowest urea dose or plain water, were put in their tank. Urea seems to send a smelly signal to these prey fish to “Sit tight – Something scary this way comes”. And the more urea in the water, the scarier!

But wait a minute: Does this mean that every time a fish takes a wiz, all his buddies run and hide? That would be ridiculous. Not only do freshwater fish pee a LOT, many are also regularly releasing urea through their gills (I know, gross, right? But not nearly as gross as the fact that many cigarette companies add urea to cigarettes to add flavor).

The researchers figured that background levels of urea in the water are inevitable and should reduce fishes fear responses to urea. They put cichlids and trout in tanks with water that either had a low level of urea, a high level of urea, or no urea at all. Then they waited 30 minutes, which was enough time for the fish to calm down, move around and eat normally. Then they added an additional pulse of water, a medium dose of urea, or a high dose of urea. Generally, the more urea the fish were exposed to for the 30 minute period, the less responsive they were to the pulse of urea. Just like the scientists predicted.

A rainbow trout smells its surroundings.
Photo at Wikimedia taken by Ken Hammond at the USDA.

But we still don’t know exactly what this means. Maybe the initial dose of urea makes the fish hide at first, but later realize that there was no predator and decide to eat. Then the second pulse of urea may be seen by the fish as “crying wolf”. Alternatively, maybe the presence of urea already in the water masks the fishes’ ability to detect the second urea pulse. Or maybe both explanations are true.

Urea, which is only a small component of freshwater fish urine, is not the whole story. Urea and possibly stress hormones make up what scientists refer to as disturbance cues. Steroid hormones that are involved in stress and sexual behaviors play a role in sending smelly signals in a number of species, so it makes sense that stress hormones may be part of this fearful fish smell. But fish also rely on damage-released alarm cues and the odor of their predators to know that a predator may be near. Scientists are just starting to get a whiff of what makes up the smell of fear.

Want to know more? Check these out:

1. Brown, G.E., Jackson, C.D., Malka, P.H., Jacques, É., & Couturier, M-A. (2012). Disturbance cues in freshwater prey fishes: Does urea function as an ‘early warning cue’ in juvenile convict cichlids and rainbow trout? Current Zoology, 58 (2), 250-259

2. Chivers, D.P., Brown, G.E. & Ferrari, M.C.O. (2012). Evolution of fish alarm substances. In: Chemical Ecology in Aquatic Systems. C. Brömark and L.-A. Hansson (eds). pp 127-139. Oxford University Press, Oxford.

3. Brown, G.E., Ferrari, M.C.O. & Chivers, D.P. (2011). Learning about danger: chemical alarm cues and threat-sensitive assessment of predation risk by fishes. In: Fish Cognition and Behaviour, 2nd ed. C. Brown, K.N. Laland and J. Krause (eds). pp. 59-80, Blackwell, London.

Tuesday, October 9, 2018

Caught in My Web: Mind-Altering Substances

Image by Luc Viatour at Wikimedia Commons
Drunken birds have gone viral this week! For this edition of Caught in My Web, we wonder if animals alter their mental states like people do.

1. Drunk Minnesotan birds are flying into windows! At least that is what the viral story says. But the truth may be a bit more measured. As the Police Chief of Gilbert, Minnesota says, “It sounds like every bird in our town is hammered, and that’s not the case.” Read the real story here.

2. But do wild animals really drink alcohol? Not in the way that we do, maybe, but many consume overly fermented fruits. Some have developed a tolerance to the high alcohol content, others, not so much. Just ask this poor drunk moose that got herself stuck in a tree after eating too many fermented apples.

3. But it’s not just fermented fruits that get animals drunk. Some fish can make their own alcohol to help them survive a long winter under the ice.

4. What about the effects of other mind-altering substances on animals? Ever wonder what kind of web a spider would make on different drugs? In 1948, a zoologist at the University of Tubingen in Germany by the name of H.M. Peters did.



5. Octopuses are normally very solitary creatures… that is, unless they are given ecstasy. Apparently, even octopuses seek social interactions when they take the common party drug.

Tuesday, October 2, 2018

Friends Without Benefits: A Guest Post

A reposting of an original article by Joseph McDonald

Do you want to avoid the friend zone?
Photo by freedigitalphotos.net.
Guys DREAD the friend zone. That heart-aching moment when the girl you’ve been fawning over for years says you’re the best listener, the sister she never had, or so much better than a diary! You’ve been so nice to her and her friends, listening to all their drama. But that’s just the problem... you’re too nice to too many people.

Research performed by Aaron Lukaszewski and Jim Roney at the University of California – Santa Barbara (UCSB) tested whether preferences for personality traits were dependent on who the target was. In Experiment 1, they asked UCSB undergrads, on a scale from 1 to 7, the degree to which their ideal partner would display certain traits towards them and towards others. These traits included synonyms for kindness (e.g. affectionate, considerate, generous, etc.), trustworthiness (committed, dependable, devoted, etc.), and dominance (aggressive, brave, bold, etc.). Experiment 2 replicated the procedures of Experiment 1. The only difference was that the term “others” was divided into subsets including unspecified, family/friends, opposite sex non-family/friend, and same-sex non-family/friend.

Let’s go over the do’s and don’ts so that future “nice guys” aren’t friend zoned. According to the findings, as graphed below:

Figure from Aaron and Jim's 2010 Evolution and Human Behavior paper.
1. Women generally prefer men who are kind and trustworthy. So, to get that girl, don’t be mean; that’s not the point. This isn’t 3rd grade so don’t pull her hair and expect her to know that you LIKE-like her.

2. Women prefer men who are kinder and more trustworthy towards them than anyone else. So it’s not so much whether you are nice enough, its whether she knows you are nicer to her than anyone else.

3. Women prefer men who display similar amounts of dominance as they do kindness. Dominance isn’t a bad thing, as long as you can distinguish her friends from her foes; especially her male friends.

4. To make things more complicated, women also prefer men who are directly dominant toward other men but don’t display dominance toward them or their family/friends, whether male or female. Some guys may want to befriend these other men, but be weary. Women preferred dominance over kindness in this situation, so kindness may not be enough.

These preferences may have developed to avoid mating with someone willing to expend physical and material resources for extramarital relationships, and invest greater in her and the children. Moderate kindness and trustworthiness toward others will maintain social relationships and prevent detrimental relationships, which may be why women generally prefer kind and trustworthy guys. But in all fairness, women can be in the friend zone too; just look at Deenah and Vinny (excuse the shameful Jersey Shore reference).

There are some things that guys look for in a mate, so ladies, here is a little advice:

1. Guys generally want a mate who is kind and trustworthy, too. We’re not that different; so don’t act a little crazy because you think he likes it. He doesn’t.

2. Guys also prefer women who display dominance toward other women (non- family/friend). Don’t be afraid to put that random girl with the prying eyes in her place.

Contrary to the hypotheses predicting female mate preferences, male mate preferences may have developed as a way to take advantage of strong female-based social hierarchies. No matter what the reasoning, however, if you can
1) be kinder and more trustworthy towards that special someone than anyone else and
2) display dominance over other same-sex people, then feel free to say good-bye to the friend zone!


For further details, check out the original experiment:

Lukaszewski, A., & Roney, J. (2010). Kind toward whom? Mate preferences for personality traits are target specific Evolution and Human Behavior, 31 (1), 29-38 DOI: 10.1016/j.evolhumbehav.2009.06.008

Tuesday, September 25, 2018

Caught in My Web: We Are Primates

Image by Luc Viatour at Wikimedia Commons
If the news cycle these days has you wondering about our own humanity, take a moment to reflect on our primate nature. For this edition of Caught in My Web, let's explore primate behavior in the news.

1. Elizabeth Preston at Discover writes about lemur "stink flirting" in High-Ranking Male Primates Keep Wafting Their Sex Stink at Females, Who Hate It.

2. Janelle Weaver discusses how primates grant favors for their own social benefit at Nature in Monkeys Go Out on a Limb to Show Gratitude.

3. Roxanne Khamsi at NewScientist reports that Envious Monkeys Can Spot a Fair Deal.

4. Writing for The Verge, Angela Chen explains how we discovered that bonobos prefer to befriend bullies in For Bonobos, Nice Guys Finish Last.

5. In Those Lying Apes, Dale Peterson of Psychology Today discusses chimpanzee deception.

Sound familiar?

Tuesday, September 18, 2018

Epigenetics: The Fusion of Nature and Nurture (A Guest Post)

A reposting of an original article by Tricia Horvath on August 14, 2013.

For decades scientists have been debating what makes a person who they are. Is someone’s personality, appearance, and medical history determined by their nature (their hardwired genes with the environment playing no role) or nurturing (how they were raised, and what they encountered in their environment growing up)? Many scientists were convinced that only one of these things, nature or nurture, could be responsible for determining a person’s fate. For instance, those who believed in nurture as the prevailing force thought that a person’s specific genes had nothing to do with how they behaved. Although ample evidence has been built up on both sides, scientists now know that the answer is actually both!

If you need convincing, just think about identical twins. Identical twins are genetic clones (all of their genes are exactly the same). These twins are very similar to each other in many ways such as physical appearance and personalities, even if they are separated at birth and raised apart from one another. However, anyone who has spent significant time with identical twins knows that each twin is their own person, and as they get older and spend less time together the personalities of the twins will continue to diverge. If nature (just genes) was in charge, identical twins would be the same in every respect. If nurture (just environment) was in charge, identical twins would be no more similar than any pair of siblings.

Genes are like pages in an
instruction manual for ourselves.
If genes are the pages in our
instruction manual, then DNA
is the actual book. Image by
tungphoto at freedigitalfotos.net.
So how is any of this possible? The answer lies in a field called epigenetics. Epigenetics studies how the environment interacts with genes to change their expression. Genes are like pages in an instruction manual for ourselves. In order for certain traits to be expressed, these genes/pages need to be read. If a gene cannot be read, then the trait it represents will not be expressed.

The environment plays a large role in determining which genes can be read, and therefore what traits are expressed. However, if a person does not have the genes for a specific trait (their book does not have those pages) that trait could never be expressed. For example, no matter how much time you spend in the water growing up, you will never grow a mermaid tail because you don’t have the genes for a mermaid tail. In this example, spending a lot of time in the water growing up would be part of your nurturing, and the lack of genes for a mermaid tail would be part of your nature. Even though having a mermaid tail would be beneficial in the water, the environment cannot interact with your genes to give you a mermaid tail because you simply don’t have the genes. Therefore epigenetics only works if you have the right genes.


How does epigenetics work?


DNA is the long strings of genetic material that are found in every cell (and every cell has exactly the same DNA). Genes are strung together on the DNA strings: If genes are the pages in our instruction manual, then DNA is the actual book. Each gene has a section with “read” or “don’t read” signs. The gene will be read, or not read depending on which of these signs is showing. The environment can determine which genes are read (and therefore which traits are expressed) by covering up these signs.
You’re less likely to stop if you don’t see the sign.
Photo by Nicholas A. Tonelli at Flickr.

The first player in covering up one of these signs is a methyl mark. Methyl marks are little chemical tags that get attached to certain parts of DNA. Methyl marks have two jobs. First, they partially cover up one of the signs (“read” or “don’t read”). Second, they help attract proteins that can help completely cover up the sign.

Before we talk about these other factors, it is important to understand a few structural aspects of DNA. DNA exists in cells loosely wrapped around proteins called histones. This looks like beads (histones) on a string (DNA). DNA wraps around histones easily because DNA is negatively charged and histones are positively charged, and oppositely charged things attract one another. (Think about magnets that stick together when the opposite poles are facing each other, but repel each other when the same poles are facing each other.) In order to keep the DNA from wrapping too tightly around the histones, acetyl groups are added to the histones. Acetyl groups cover up the positive charges on the histones. This makes the histones less positively charged so they don’t attract the DNA as strongly. (This would be like making one of the magnets less strong. It is easier to pull apart two magnets that aren’t strongly attracted to each other.)

This diagram of epigenetic mechanisms is by NIH at Wikimedia Commons.

When methyl marks are present on DNA they attract proteins that remove the acetyl groups. This causes the DNA to wrap around the now more positively-charged histones very tightly. (The magnet is stronger now). When a whole section of a gene becomes wound up this tightly it leads to a complete covering up of the “read” or “don’t read” sign. Sometimes this can also happen on part of the gene that would normally be read (the actual page of the instruction manual). If enough of the gene is covered up by the DNA wrapping too tightly around the histones, then the gene cannot be read (imagine if there was a large object covering the page you wanted to read in the instruction manual).

Once a “read” or “don’t read” sign is covered up, it is not necessarily covered up for the rest of your life. Instead, the environment can remove methyl marks from DNA and add acetyl groups back onto the histones (covering up the positive charge on the histones, making them attract the DNA less strongly). This would uncover the sign and allow it to be read once more.

All of this means that traits (including behavior) may be influenced by both genes and the environment. Although the genes we are born with only make it possible for us to express certain traits, our environment helps determine which of those traits are actually expressed. If our environment changes, the traits we express can change! Because we can change our environments, we have the power to change ourselves!

Tuesday, September 11, 2018

Exploring How Predators Hunt

By Jon Clark

A "Lion King" in his natural habitat. Photo by Jon Clark.
Predatory animals are a huge obsession for most children at some point. From that picture book about the cool T-Rex to watching “The Lion King” millions of times, we’re fascinated with the kings of the food chain. And let’s be honest, even as adults they’re still pretty neat to us. Why else take a grand safari adventure to see lions and other animals in their natural habitat? So to fuel that curiosity, below is a guide to how predators hunt. It might just help you understand animal movements and behavior for watching wildlife.


The basics of how predators hunt


Predators are, of course, animals that feed on other animals. These predators rely on the flesh of other animals as a resource for their survival and are highly skilled at finding and catching it. Predators sit at the top of a delicate food web, all components of which fit together to keep the environment balanced over time.

Different types of predators have four main hunting strategies for finding their prey. According to an article from Idaho Public Television, they are:

  • Chase: Think of an eagle diving for a mouse. This is chase behavior in predators. This method requires a delicate balance of hunting down food that provides enough energy and nutrition to offset the energy cost of running that food source down.

  • Stalk: For this method, think of an egret or crane standing motionless or walking slowly in water, and then lunging as a tasty morsel goes by. This method is a huge time sink for the animal as it moves from cover to cover getting incrementally closer to it’s prey. It also takes far less energy, however, as only a small burst of speed is required at the end. This means that these predators can often live off of smaller prey. 

  • Ambush: Lion researcher, George Schaller, watched a group of gazelles in the Serengeti. In order to access water, there was a patch of thick brush they would need to cross. As the gazelles entered the brush, Schaller watched as the lions hiding in wait, instantly ambushed and ate one of the gazelles. Due to their long manes and tan color, lions are nearly undetectable in such cover. The ambush requires a great deal of time, as it relies on other animals to wander into the area. For predators that have the patience, the success rates are quite high.

  • Teamwork: Think of wolves working as a pack to take down a deer. This is one of the most exciting ways of how predators hunt. Teamwork allows the animals to pursue large and fast prey, scoring large amounts of food for the group. This is arguably one of the most successful tactics as seasoned hunters can quickly steer their prey in the direction of the other party. Additionally, the energy required for the chase and kill can be dispersed across the collective group. 


Lions on the hunt


One of the coolest and most popular things to see on a safari is a lion in its own natural habitat. This mighty “King of the Jungle” hunts both independently and as part of groups. Lions hunt some of the fastest animals in the world, like the wildebeest, which can run at speeds of 50 mph. Lions themselves are not incredibly fast, so they’ve had to get smart through a variety of hunting strategies.

Because lions are also relatively lazy animals, they tend to eat larger animals – which sustain them for longer periods. These animals include antelopes, zebras and wildebeest.

A lioness. Photo by Jon Clark.

The female lionesses hunt the most often for both themselves and for the males. A lioness will stalk from cover to cover to get close to the prey animal, and then pounce at the last minute. Their prey usually has slower reaction times, so this is a solid method. If the prey sees them, the lion will act innocent by sitting up and staring off into the distance, as if to say, “I wasn’t doing anything.”

Another method lions use is to find a bush near where the prey goes often, like a watering hole, and wait until they can strike. Lions have been known to actually nap while awaiting their deadly ambush.

To catch large or fast prey, lions leverage their group numbers to help each other cut off the escape of fleeing prey. When lions decide to hunt in pairs and groups their success rate goes up from about 18 percent to 30 percent while hunting alone and in daylight, according to the African Lion & Environmental Research Trust.

When hunting in groups, lions stalk in a pattern to encircle the prey. Then some attack, driving the prey to other waiting lions. As the prey animal tires from the constant running, one or two lionesses will try to jump on the back of the animal or hang by their claws from a zebra's or gnu's or buffalo's back. This certainly makes it very hard for the poor animal to run away from the next lion, who goes for the throat to complete the hunt. It’s one of the smartest and most effective ways for how predators hunt.

Hungry cubs waiting for lunch. Photo by Jon Clark.

Lions are known for their advanced hunting skills and have mastered the art of teamwork in all of their hunting strategies, including chasing, stalking, and ambushing their prey. Embarking on an African safari will be your best chance to experience these master hunters in real life.

Tuesday, September 4, 2018

Why Ask for Directions? (A Guest Post)

A reposting of an original article by Anna Schneider on Feburary 8, 2016.

For the iconic monarch butterfly, the shorter days in fall mean it’s time to pack up and head south to a warmer climate! Just like clockwork, the Eastern population of monarch butterflies makes a 2000 mile journey to their winter paradise roosts in central Mexico. The journey in itself is one of the greatest migrations among all animals.

But here’s the catch: none of these butterflies has made this trip before. Several generations of monarchs have come and gone over the course of a summer, but the generation born in late August and early September are genetically prepared for months of survival without feeding or breeding. But their predecessors didn’t exactly leave them with a map. How do they know where to go? Do they have a map and compass inside their heads? The answer: yes! Well, sort of…

Think about this: if you were lost in the woods and needed to find south, what would you do? Here’s a hint: look up! The sun can be a great resource when you’re lost, and I’m not talking about just asking it for directions. As the Earth rotates on its axis throughout the day, the sun appears to travel overhead. By knowing approximately what time of day it is, you can determine the cardinal directions. Monarchs use specialized cells or organs called photoreceptors that respond to light to establish the position of the sun.

Representation of time compensated sun compass orientation used by monarchs;
Image created by Anna Schneider.
Until recently, it was thought that monarchs simply used the photoreceptors on the top portion of their compound eyes, called the dorsal rim. Past studies have shown that the signals are passed from the photoreceptors on to the “sun compass” region in their brains and the butterflies change direction based on that information. Like most animals, it was assumed that their internal clock was located inside their brains. However, recent research has demonstrated that individuals whose antennae have been painted or removed altogether become disoriented when placed in flight simulators. These monarchs do not adjust for the time of day when trying to fly south. When those same antennae that were removed were placed in a petri dish, they continued to respond to light and showed signs that they continued the pattern of time. This indicates that antennae and the brain are both needed for the monarchs to correctly determine their direction.

Diagram of features on the head of a monarch butterfly; Image created by Anna Schneider.
Now, estimating which way is South might be fine and dandy on a bright sunny day, but what happens when it’s cloudy? Not a problem for these super-insects! In another recent study, researchers tethered monarchs to flight simulators and altered the magnetic field conditions to see what would happen. When the magnetic field was reversed so magnetic North was in the opposite direction, the butterflies altered their bearings and flew exactly opposite as well. This suggests that monarchs could have some sort of way to detect the earth’s magnetic field, called magnetoreception, which could enhance the photoreception capabilities.

Many of the mechanisms behind the migration of these incredible creatures are yet to be discovered, but much progress has been made in the past decade. So next time you see a monarch butterfly, take a second look. There is more than meets the eye.

Sources:

Gegear, R., Foley, L., Casselman, A., & Reppert, S. (2010). Animal cryptochromes mediate magnetoreception by an unconventional photochemical mechanism Nature, 463 (7282), 804-807 DOI: 10.1038/nature08719

Guerra, P., Gegear, R., & Reppert, S. (2014). A magnetic compass aids monarch butterfly migration Nature Communications, 5 DOI: 10.1038/ncomms5164

Merlin, C., Gegear, R., & Reppert, S. (2009). Antennal Circadian Clocks Coordinate Sun Compass Orientation in Migratory Monarch Butterflies Science, 325 (5948), 1700-1704 DOI: 10.1126/science.1176221

Steven M. Reppert. The Reppert Lab: Migration. University of Massachusetts Medical School: Department of Neurobiology.

Wednesday, May 23, 2018

Summer Break!

The school year is winding down and summer will soon be upon us. The Scorpion and the Frog is on break, but we'll be back with more animal stories in September! Enjoy the small moments... like this adorable baby elephant at the beach for the first time:



Wednesday, May 16, 2018

Reduce Stress with this Animal Behavior Meditation

A reposting of an original article from March 21, 2012.

In a search for the promised inner peace and tranquility of meditation, I attended a meditation class at a local yoga studio. In a room with dim fluorescent lights and an artificial wood floor I laid on my back on my yoga mat, sandwiched between a fidgety woman who kept her smartphone on the edge of her mat and a man whose stress had apparently resulted in a flatulence problem. I was told to close my eyes, breathe deeply, and think about nothing. I closed my eyes, took a deep breath, and thought: “How do I think about nothing?” I thought about black. “Does black count as nothing? Wondering if I’m thinking about nothing is definitely not nothing. Am I doing this wrong? Is this going to work? If this isn’t going to work, I’m just wasting my time. I could be working through my to-do list right now. Oh! I forgot to put laundry on my to-do list. Oh, right… think about nothing. Black?


This ring-tailed lemur has found her inner peace - Can you find yours?
Photo by Margaret at Wikimedia Commons

It was years later that I realized that meditation doesn’t have to be so painfully contrived. I do it all the time naturally. Maybe you do too. We just have to nurture those moments. Here’s one way to do it:

1) Go to a place where you have seen at least one animal in the recent past. Maybe you saw a squirrel or a songbird in that tree in your yard. Maybe you saw fish in the creek you pass over on your way to school. Maybe there’s an occupied spider web in the corner. Maybe you have a favorite spot at the local zoo or aquarium. Go there. Don’t worry if there is an animal there now or not.

2) Sit down in a comfortable position and take a deep breath. Look around and take in your surroundings. Feel the environmental conditions. Listen to the sounds around you. Wait and observe. If you’re quiet, they will come.

3) When an animal shows up, focus on it. If multiple animals show up, pick one to be your focal animal. Observe every possible detail of your focal animal: What does it look like? Does it have any markings? What is it doing? How does it position itself with respect to its surroundings? What is its posture? How does it respond to changes in its surroundings?

4) Allow your mind to wander into your focal animal’s world (or umwelt). How do you think your focal animal perceives its surroundings?

5) Allow your mind to ponder explanations and consequences of your focal animal’s behavior.

6) Continue for as long as you can keep your mind focused on your animal, or until you have somewhere else you are supposed to be.

Try this out for yourself, and then let us know what you experienced!

Tuesday, May 8, 2018

The Beginnings of Jurassic Park: Dinosaur Blood Discovered? (A Guest Post)

A reposting of an original post by Samantha Vold on February 9, 2015.

The classic tale of Jurassic Park, where dinosaurs once again walked the earth has tickled the fancy of many a reader. Dinosaur DNA preserved in a fossilized mosquito was used to bring these giants back to life. But in real life, it was previously thought that there was no possible way for organic materials to be preserved, that they often degraded within 1 million years if not rapidly attacked by bacteria and other organisms specialized in decomposition. Skin and other soft tissues, such as blood vessels, would never withstand the test of time. Or would they…?

T. rex skeleton at Palais de la découverte. Image by David Monniaux at Wikimedia

In 1992, Mary Schweitzer was staring through a microscope at a thin slice of fossilized bone, but this bone had something unusual. There were small red disks located in this tissue and each had a small dark circle in the middle resembling a cell nucleus, the command center of the cell. And these little disks very much resembled the red blood cells of reptiles, birds, and other modern-day vertebrates (excluding mammals). But it wasn’t possible, was it? These cells came from a 67 million-year old T. rex. And it was commonly accepted that organic material never lasted that long.

Comparison of red blood cells. Image by John Alan Elson at Wikimedia

This opened a huge controversy in the scientific community, but Schweitzer persisted. She consulted with her mentor, Jack Horner, a leading scientist in the paleontology field, and he told her to prove to him that they weren’t red blood cells. Schweitzer took the challenge and began to run some tests.

The first clue to these mysterious scarlet-colored cells potentially being red blood cells was the fact that they were located within blood vessel channels of the dense bone that were not filled with mineral deposits. And these microscopic structures only appeared inside the vessel channels, as would be true of blood cells.

Schweitzer then began to focus on the chemical composition of these puzzling structures. Tests showed that these “little red round things” were rich in iron, and that the iron was specific to them. Iron is important in red blood cells as it helps to transport oxygen throughout the body. And the elemental make-up of these little red round things differed greatly from the surrounding bone and sediment around them.

The next test was looking for heme, a small iron-containing molecule that gives blood its characteristic color and allows hemoglobin proteins to transport oxygen throughout the body. Schweitzer tested for this through spectroscopy tests, which measure the light that a given material emits, absorbs, and scatters. Her results from these tests were consistent with what one would find in heme, suggesting that this molecule existed in the dinosaur bone she was analyzing.

Schweitzer then conducted a few immunology tests to see if she indeed had found hemoglobin in these ancient bones. Antibodies are produced when the body detects a foreign substance that could potentially be harmful. Extracts from the dinosaur bone were injected into mice to see if antibodies were produced to ward against this new organic compound. When these antibodies were then exposed to hemoglobin from turkeys and rats, they bound to the hemoglobin. This suggested that the extracts that caused an antibody response in the mice included hemoglobin. This in turn suggested the T. rex bone contained hemoglobin, or something very similar.

Through years of research, Schweitzer has shown that what was once believed to be impossible is indeed true. Soft tissues, blood cells, and proteins can withstand the test of time. This process is possibly done through iron binding to amino acids (the molecules that make up proteins) and thereby preserve them. Research is advancing in this area, but as of yet, no DNA has been found to bring Jurassic Park to life. But for the avid believer, don’t get up hope yet. Perhaps one day we truly could walk amongst dinosaurs.


References:

Fields, Helen. (May 2006). Dinosaur Shocker. Smithsonian. Smithsonian Magazine.

Pappas, Stephanie. (13 Nov. 2013). Mysteriously Intact T. Rex Tissue Finally Explained : DNews. DNews. Live Science.

Schweitzer, M. (2010). Blood from Stone Scientific American, 303 (6), 62-69 DOI: 10.1038/scientificamerican1210-62

Tuesday, May 1, 2018

Mr. Nanny Makes Mr. Right

A reposting of an original article from November 28, 2012.

Quick! Introduce yourself to this guy before
his baby-high wears off! Photo by David
Castillo Dominici at FreeDigitalPhotos.net
What happens if you take a wrestler or action star and force him to babysit obnoxious but lovable kids? Well, if you’ve seen movies like The Pacifier with Vin Diesel, The Tooth Fairy with Dwayne ‘The Rock’ Johnson, Kindergarten Cop with Arnold Schwarzenegger, or The Spy Next Door with Jackie Chan, you know that he will fall madly in love both with his young charges and with the closest available woman. Hollywood is so sure of this phenomenon that they have based a whole genre of family movies on it. Now, scientists are finding that Hollywood may be on to something.

Prairie voles are one of the only 3-5% of mammals that are monogamous and in which both parents help take care of young. In females, maternal care is regulated in part by the hormones associated with pregnancy, birth and lactation. The fact that males don’t do those things and they still provide paternal care is curious. The fact that male prairie voles will often provide care to offspring that aren’t even their own is even more curious.

Will Kenkel, Jim Paredes, Jason Yee, Hossein Pournajafi-Nazarloo, Karen Bales, and Sue Carter at the University of Illinois at Chicago recently explored what happens to male prairie voles when they are exposed to unfamiliar vole pups. Male voles without any experience with females or pups were placed in a new clean cage. Then the researchers put either a pup (that was not related to the male), a dowel rod (an unfamiliar object), or nothing into the cage with them for 10 minutes. Afterwards, they measured oxytocin (a hormone associated with bonding between mothers and their offspring) and corticosterone (a stress hormone) in the males’ blood at different time points. In another study, they also looked at the activity of brain neurons associated with the production of these hormones.


A male prairie vole is startled to find a baby in his cage...
But then he takes care of it. Video by Will Kenkel.

Both adult and juvenile males exposed to a pup for 10 minutes had higher oxytocin and lower corticosterone compared to the males not exposed to a pup. But this effect was short-lived, as male hormone levels quickly evened out again. Most of these males that were exposed to a pup showed alloparental care (care of a baby that is not their own), like approaching the pup, cuddling with it and grooming it. Males with higher oxytocin and lower corticosterone levels were more attentive towards the pups. Additionally, alloparental males exposed to pups had more activity of oxytocin-producing neurons and less activity of neurons associated with corticosterone-production in a specific brain region called the paraventricular nucleus (or PVN for short).

Oxytocin is strongly associated with pair bonding in prairie voles, particularly in females, and corticosterone affects pair bonding too (generally increasing pair bonding in males and preventing it in females). If exposure to a pup affects these hormones, maybe it affects how the male would interact with adult females. To test this, the researchers put male voles in a new clean cage and put a pup, a dowel rod, or nothing into the cage with them for 20 minutes. Then they put the males with an unfamiliar adult female for 30 minutes. After getting acquainted with the female, the males were put in a “partner preference apparatus”, which has three connected chambers: a neutral center chamber, a connected chamber with the familiar female tethered into it, and a connected chamber with an unfamiliar female tethered into it. The researchers measured how much time the males spent in each of the three chambers and with each of the two females over the next 3 hours.



A prairie vole pair snuggles. Photo from Young,
Gobrogge, Liu and Wang paper in
Frontiers in Neuroendocrinology (2011)
Males that were exposed to a dowel rod or to nothing before they were introduced to a female spent equal amounts of time with each of the two females. But males that were exposed to a pup before they were introduced to a female spent nearly 4 times as much time with that female than with the unfamiliar one. In other words, hanging out with a random pup acted like Love Potion #9 on these bachelor males and made them fall for the next female they encountered! Interestingly, this effect was true not only for the males that acted in an alloparental way towards the pups, but it was also true of males that attacked the pups (The researchers quickly rescued the pups if this occurred). Perhaps, males that were alloparental with the pups had increased oxytocin and males that were aggressive with the pups had increased corticosterone, either of which would make it more likely for them to form a preference for the female they were with.

Hmm… Got your eye on a special someone? Try volunteering him to babysit before your next date.

Want to know more? Check this out:

Kenkel, W., Paredes, J., Yee, J., Pournajafi-Nazarloo, H., Bales, K., & Carter, C. (2012). Neuroendocrine and Behavioural Responses to Exposure to an Infant in Male Prairie Voles Journal of Neuroendocrinology, 24 (6), 874-886 DOI: 10.1111/j.1365-2826.2012.02301.x

Tuesday, April 24, 2018

What To Do If You Find Orphaned Wildlife

A repost of an original article on April 11, 2016.

A nest of baby cottontails waiting for sunset when their
mom will return. Image by Jhansonxi at Wikimedia.
Spring is finally in the air, and with Spring come babies! Finding baby animals in the wild is thrilling, but also concerning. Does this animal need your help? Where is its mom? What do you do?

Whenever possible, baby animals will do best when we leave them in the care of their mom. Even a well-meaning human is seen by a wild animal as a threat. Our interactions with them cause them extreme stress that can cause serious health problems and even death. Furthermore, if we take a baby animal home, it will not be able to learn its species-specific behaviors and skills and it can lose its natural and healthy fear of humans. It is also very hard to meet the specialized dietary needs of a wild animal in a captive setting. Taking a wild animal home can cause problems for us as well: many carry diseases that can be transmitted to our pets or even ourselves. And most wild animals are protected by state and federal laws that prohibit unlicensed citizens from possessing or raising them.

Luckily, most baby animals that seem alone actually have a mom that is not far away, either looking for food to feed herself and her babies or simply hiding from you. For example, rabbit mothers actively avoid their nests most of the time so as to not attract predators to the nest. Cottontail moms visit their babies only briefly at dawn and dusk for quick feedings. If you find a bunny nest, you can test to see if the mom is visiting by placing a few blades of grass or thin twigs in an X-shape over the babies. If you come back the next day and the pattern has been disturbed, then their mom is still caring for them and you should leave them be.

Many animal moms are prevented from taking care of their young when concerned people are hovering. Deer moms, for example, also actively avoid their babies (called fawns) so as to not attract predators to it. They generally return to nurse the fawns every few hours, but they won’t return to nurse if people or pets are around. If you find a fawn and it is not wandering and crying non-stop all day, then leave it alone so its mom will come back.

A red fox mom and baby. Photo by Nicke at Wikimedia.

Even if you find a baby all by itself in the open, the best course of action is often still to leave it alone. Many mammal moms, like squirrels, raccoons, mice, rats, foxes, and coyotes, will retrieve their young if they fall out of their nest or wander away from their den. Although it is a myth that most animal moms will abandon their babies if you get your smell on them, your odor can attract predators. It is best not to touch wildlife babies if you can avoid it.

Awww... as tempting as it is to pick up an adorable baby skunk, don't do it
unless you are a trained and licensed wildlife rehabilitator (like this woman is).
Image by AnimalPhotos at Wikimedia.

So when should you get involved? If an animal is in a dangerous location (like a busy street), then it may need to be moved. You can slowly, quietly and gently try to guide a mobile baby animal away from hazards and to a safer location. If the animal is not yet mobile, in most cases, you can use clean gloves to pick up the animal and move it to a safer location, placing it as close as possible to where you found it.

If you know that the mom is dead or has been relocated, then you are dealing with a truly orphaned baby animal. Likewise, if an animal has been attacked (or brought to you by your “helpful” cat), or is bleeding, injured, wet and emaciated, weak, infested with parasites, or has diarrhea, then it may need medical attention. In these cases, contact a licensed wildlife rehabilitator. Wildlife rehabilitators have been trained and have the necessary equipment to temporarily care for and treat injured, sick and orphaned wild animals so they can be released back into the wild. If you can’t find a wildlife rehabilitator, contact the Department of Natural Resources, a state wildlife agency, animal shelter, humane society, animal control agency, nature center, or veterinarian. Ideally, they will come to pick up the animal themselves. If they can’t, then they should give you detailed instructions for your situation on how to catch and transport the animal.

For more information, check here:

The Humane Society of the United States

The Wisconsin Department of Natural Resources

The Virginia Department of Game and Inland Fisheries

Tuesday, April 17, 2018

Birds, Vitamin E, and the Race Against Time: A Guest Post

A repost of an original article by Alyssa DeRubeis on February 6, 2013

The long and tapered wings on this young
Peregrine Falcon means it was built for some
serious speed! Photo by Alyssa DeRubeis.
Maybe you’ve been put under the false assumption that humans are cool. Don’t get me wrong; our bodies can do some pretty neat physiological stuff. But I’m gonna burst your bubble: humans are lame. Just think of how fast we can run compared to a Peregrine Falcon in a full stoop: 27 MPH versus 242 MPH.

Keep thinking about all the cool things birds can do. It doesn’t take us long to realize that our feathered friends are vastly more fascinating compared to humans. Now that you’re finally admitting defeat, I ask that you read on.

The most amazing avian physiological feat is the ability to travel long distances seasonally (a.k.a migrate). Between poor weather conditions, preventing fat loss, and staying alert, migration is not easy by any means. However, birds can cope with all of these things by assimilating and using antioxidants like vitamin E.

Here’s a classic bird migration scene: thousands of Tundra Swans, geese, and ducks congregate on the Mississippi River in Minnesota. Here, they rest and refuel before continuing their journey south. Photo by Alyssa DeRubeis.

Let’s talk a little bit about bird migration. It’s a two-way street, where a migratory bird will (usually) fly north as soon as possible to rear its young, and then fly south where it can stay warm and eat all sorts of goodies. During these two bouts of intense exercise, the birds produce free radicals, which are types of atoms, molecules, and ions that can harm DNA and other important stuff inside the body. This is where vitamin E comes in to save the day, because this vitamin, along with vitamin A and carotenoids, are antioxidants. They drive away bad things like free radicals from birds’ bodies; some scientists suggest that they may even reduce risks of cancer! In the case of migrating birds, antioxidants can make this migration headache a lot more bearable.

Well, that’s great. But where do these antioxidants come from? The short answer is avian nom-noms, but it’s one thing to eat something with an antioxidant in it. It’s quite another to actually be able to assimilate and use this antioxidant. Okay…so where do the birds get this ability from? It’s parentals!

Anders Møller from the University of Paris-Sud, along with his international team including Clotilde Biard (France), Filiz Karadas (Turkey), Diego Rubolini (Italy), Nicola Saino (Italy), and Peter Surai (Scotland), pointed out that there is little research looking at maternal effects on our feathered friends. Møller hypothesized that maternal effects (the direct effects a mother has on her offspring) play a critical role in migration: If mothers put a lot of antioxidants in their eggs, the chicks will be able to absorb antioxidants better later in life. This would give these birds a competitive edge because they will migrate in a healthier condition and arrive to breeding grounds earlier.

This male Barn Swallow on the left must’ve gotten back pretty early for him to have landed himself such a beautiful female. Thank you, Vitamin E! Photo by Alyssa DeRubeis.

In the early 2000s, Møller and his five colleagues collected 93 bird species’ eggs. The crew was able to analyze how the natural differences in antioxidant concentrations (put in by the mother) related to the birds’ spring arrival dates in 14 of them. They found that vitamin E concentration, but not vitamin A concentration, was a reliable predictor of earlier arrival dates.

This European posse took it a step further by injecting over 700 barn swallow eggs with either a large dose of vitamin E or a dose of corn oil (which contains a small amount of vitamin E). It was soon evident that the chicks with more vitamin E were bigger than chicks that received less vitamin E, thus already giving the big chicks a competitive edge over their less vitamin E-affiliated brethren. The researchers kept track of the eggs that hatched out as males in the following spring via frequent mist-netting sessions (a bird-capturing technique). Guess what? The fellas with higher vitamin E concentrations arrived earlier on average by ten days than those with lower concentrations!

Sweet. But what does it all mean? First off, vitamin E is crucial for migratory birds because it allows them to process antioxidants more efficiently. In fact, another study done by Møller, Filiz Karadas, and Johannes Emitzoe out of University of Paris-Sud suggested that birds killed by feral cats had less vitamin E than birds that died of other reasons. Furthermore, the early birds get the worm. Events such as insect hatches—vital for baby birds—now occur earlier in the spring as temperatures rise (read: climate change). Plus, if you’re a male arriving at the breeding grounds early, you get to pick the best spots to raise your offspring.

Wood-warblers, such as this Palm Warbler, must get back to their northerly breeding grounds in a timely fashion in order to hit the insect hatch for da babies. Photo by Alyssa DeRubeis.

Obviously, there’s an advantage to up the vitamin E intake and get a head start as a developing embryo. In an egg, most nutrients come from the yolk…which comes from the mother. The healthier the mother, the more vitamin E she will put in her eggs. And vitamin E isn’t produced internally; birds must consume it. While Møller’s paper on maternal effects states that vitamin E can be found widely in nature, a separate study found no apparent association between vitamin E and avian diet. Hmm. So then where DO birds get vitamin E from? Is it a limiting resource? Is there competition for it?

Clearly, we’ve got some questions and answers. As the field of “birdology,” advances, we will learn more and keep humans jealous of birds for years to come.

REFERENCES

1. Møller, A., Biard, C., Karadas, F., Rubolini, D., Saino, N., & Surai, P. (2011). Maternal effects and changing phenology of bird migration Climate Research, 49 (3), 201-210 DOI: 10.3354/cr01030

2. Møller AP, Erritzøe J, & Karadas F (2010). Levels of antioxidants in rural and urban birds and their consequences. Oecologia, 163 (1), 35-45 PMID: 20012100

3. Cohen, A., McGraw, K., & Robinson, W. (2009). Serum antioxidant levels in wild birds vary in relation to diet, season, life history strategy, and species Oecologia, 161 (4), 673-683 DOI: 10.1007/s00442-009-1423-9

Tuesday, April 10, 2018

How To Get Into An Animal Behavior Graduate Program: An Outline

Do you dream about a career of studying animals?
Image by freedigitalphotos.net.
A repost of an original article from March 13, 2013.

**NOTE: Although this advice is written for those interested in applying to graduate programs in animal behavior, it applies to most programs in the sciences.**

So you want to go to grad school to study animal behavior… Well join the club! It is a competitive world out there and this is an increasingly competitive field. But if every fiber of your being knows this is the path for you, then there is a way for you to follow that path. With hard work, dedication and persistence, you can join the ranks of today's animal biologists to pursue a career of trekking to wild places to study animals in their native habitats, testing questions about the physiology of behavior in a lab, or exploring the genetics of behavioral adaptation.

This is an outline of advice on how to get into a graduate program in animal behavior. More details on the individual steps will follow, so leave a comment below or e-mail me if you have any particular questions you would like me to address or if you have any advice you would like to share.


  1. Get good grades, particularly in your science and math courses. And make sure you take all the science and math prerequisites for biology graduate programs.
  2. Prepare well for the GREs.
  3. Get research experience. This can come in many forms (such as volunteering in a lab, working as a field technician, or doing an independent project for credit), but as a general rule, the more involved you are in a project, the more it will impress those making acceptance decisions.
  4. Choose the labs you are interested in, not just the schools. As a graduate student, you will spend most of your time working with your advisor and the other members of your advisor’s lab. This means that the right fit is imperative. Figure out what researchers you may want to work with, then see if they are at a school you would like to attend.
  5. Be organized in your application process. There will be a lot of details to keep straight: due dates, recommendation letters, essays, communication with potential advisors… The more organized you are, the less likely you are to miss a deadline or make an embarrassing mistake.
  6. Write compelling essays. Most schools will ask you to write two short essays: a Statement of Purpose and a Personal History. This is your place to set yourself apart. They need to convey your experience with animal behavior research and passion for working with that particular advisor. They also need to be very well written, so expect to write multiple drafts.
  7. Be organized and prepared when you ask for your recommendation letters. The easier you make it for your references to write a thoughtful recommendation letter for you, the better the letters will be.
  8. Apply for funding. This isn’t essential: Most first-year graduate students do not have their own funding. But the ability of a school and a specific researcher to accept a graduate student depends on what funding is available to support them. If you have your own funding, it is more likely you will to be able to write your own ticket.
  9. Be prepared for each interview you are invited to.
  10. If at first you don’t succeed, try and try again. Although heartbraking at the time, it is very common in animal behavior graduate programs to not be accepted anywhere in your first year of applications. If you are rejected, it doesn’t necessarily mean you are not a good candidate. Often it means there is no funding available to support you in the labs you would like to join. Spend the year participating in research and applying for funding so you can reapply next year.
The submission of a successful application takes a lot of planning and preparation. Getting good grades is a continuous effort. Plus, the most successful applicants often have two or more years of research experience. Ideally, you are working on these two things at least by your sophomore year of college. But if you waited too long and you haven’t taken enough science or math prerequisites, your grades are not where they need to be, or you don’t have enough research experience, you can take some extra time after you graduate to take community college courses and volunteer or work in a lab. Persistence and dedication are key to following a challenging path.

Tuesday, April 3, 2018

Animal Mass Suicide and the Lemming Conspiracy

A repost of an original article from April 4, 2012.

Ticked off Norway lemming doesn't like gossip!
Photo from Wikimedia Commons by Frode Inge Helland 
We all know the story: Every few years, millions of lemmings, driven by a deep-seated urge, run and leap off a cliff only to be dashed on the rocks below and eventually drowned in the raging sea. Stupid lemmings. It’s a story with staying power: short, not-so-sweet, and to the rocky point.

But it is a LIE.

And who, you may ask, would tell us such a horrendous fabrication? Walt Disney! Well, technically not Walt Disney himself… Let me explain:

The Disney Studio first took interest in the lemming mass suicide story when, in 1955, they published an Uncle Scrooge adventure comic called “The Lemming with the Locket” illustrated by Carl Barks. In this story, Uncle Scrooge takes Huey, Dewey and Louie in search of a lemming that stole a locket containing the combination to his vault … but they have to catch the lemming before it leaps with all his buddies into the sea forever. Three years later, Disney further popularized this idea in the 1958 documentary White Wilderness, which won that year’s Academy Award for Best Documentary Feature. A scene in White Wilderness supposedly depicts a mass lemming migration in which the lemmings leap en masse into the Canadian Arctic Ocean in a futile attempt to cross it.


In 1982, the fifth estate, a television news magazine by the CBC (that’s the Canadian Broadcasting Corporation), broadcast a documentary about animal cruelty in Hollywood. They revealed that the now infamous White Wilderness lemming scene was filmed on a constructed set at the Bow River in Canmore, Alberta, nowhere near the Arctic Ocean. Lemmings are not native to the area where they filmed, so they imported them from Churchill after being purchased from Inuit children for 25 cents each. To give the illusion of a mass migration, they installed a rotating turntable and filmed the few lemmings they had from multiple angles over and over again. As it turns out, the lemming species filmed (collared lemmings) are not even known to migrate (unlike some Norwegian lemmings). Worst of all, the lemmings did not voluntarily leap into the water, but were pushed by the turntable and the film crew. Oh, Uncle Walt! How could you?!

Norway lemmings really do migrate en masse, but they don't commit mass suicide.
Drawing titled Lemmings in Migration, in Popular Science Monthly Volume 11, 1877.
As far as we know, there are no species that purposely hurl themselves off cliffs to die en masse for migration. But, strangely enough, North Pacific salmon do purposely hurl themselves up cliffs to die en masse for migration. And what, you may ask, is worth such a sacrifice? Sex, of course!

Migrating sockeye salmon thinking about sex.
Photo from Wikimedia Commons by Joe Mabel.

The six common North Pacific salmon species are all anadromous (meaning that they are born in fresh water, spend most of their lives in the sea and return to fresh water to breed) and semelparous (meaning they only have a single reproductive event before they die). After years at sea, salmon swim sometimes thousands of miles to get to the mouth of the very same stream in which they were born. Exactly how they do this is still a mystery. Once they enter their stream, they stop eating and their stomach even begins to disintegrate to leave room for the developing eggs or sperm. Their bodies change in other ways as well, both for reproduction and to help them adapt to fresh water. They then swim upstream, sometimes thousands of miles more, and sometimes having to leap over multiple waterfalls, using up their precious energy reserves. Only the most athletic individuals even survive the journey. Once they reach the breeding grounds, the males immediately start to fight each other over breeding territories. The females arrive and begin to dig a shallow nest (called a redd) in which she releases a few thousand eggs, which are then fertilized by the male. They then move on, and if they have energy and gametes left, repeat the process with other mates, until they are completely spent. If the females have any energy left after laying all their eggs, they spend it guarding their nests. Having spent the last of their energy, they die and are washed up onto the banks of the stream.

Now that’s parental commitment! So the next time your parents start laying on the guilt about everything they’ve given up for you, share this nugget with them and remind them it could be worse…


Want to know more? Check these out:

1. Learn more about semelparity here

2. Learn more about salmon reproduction at Marine Science

3. And learn even more about salmon reproduction with this awesome post by science blogger and Aquatic and Fishery Sciences graduate student, Iris. Her current blog posts can be found here.

4. Ramsden E, & Wilson D (2010). The nature of suicide: science and the self-destructive animal. Endeavour, 34 (1), 21-4 PMID: 20144484