Sunday, October 13, 2019

4 Real-Life Monsters

A repost of an original article published October 26, 2015.

During the Halloween season, we find ourselves surrounded by monsters in movies, stores and decorations. We laugh at the ridiculousness of it all, oblivious to the fact that there are true monsters on our planet today! Mind you, these are not monsters in that they are evil, but they do have many of the same abilities and inclinations of our own mythical werewolves, vampires, zombies and shape-shifters.

Werewolf birds:

A Barau's petrel. Photo by SEOR
available at Wikimedia Commons.
Barau’s petrel is a migrating sea bird that is most active during nights with a full moon. Researchers tied bio-loggers on the birds’ feet to track their activity levels and found that under the full moon, the birds spent nearly 80% of these moonlit nights in flight! It is thought that since these birds migrate longitudinally (parallel with the equator), they can’t use changes in day length as a cue to synchronize their breeding, so they use the phases of the moon instead.

Vampire bats:

Three different bat species feed solely on blood: the common vampire bat, the hairy-legged vampire bat and the white-winged vampire bat. Feeding on blood is not uncommon – The actual term for it is hematophagy, and it is common in insects (think of those pesky mosquitos) and leeches. Although we don’t commonly think of it this way, blood is a body tissue and, like meat, it is rich in protein and calories. The reason it has not become a more popular food source among mammals is probably because it is so watered down (literally) compared to meat, that it can’t provide enough nutrition to sustain a large warm-bodied mammal. This is where our little vampire bat friends come in… small, stealthy, and with specialized saliva that prevents their victims’ blood from clotting, these guys are able to take advantage of this abundant resource, drinking up to half of their body weight in blood every night.


Scientists have recently discovered some strange honey bees: They mindlessly leave their hives in the middle of the night and fly in circles, often towards lights. It turns out that these honey bees are being parasitized by a species of phorid fly called the zombie fly. Female phorid flies lay their eggs inside the abdomens of honey bees, where the eggs hatch into larvae. The larvae feed on the insides of their bee hosts until they are mature enough to leave through the poor bee’s neck (the honey bee is generally dead by this time). Once out, the zombie flies develop into adults so they can breed and start the cycle anew with a new bee host. This phenomenon is still in the early stages of discovery, so if you would like to get involved in this project by watching honey bees in your area, check out ZomBee Watch, a citizen science project to track this zombie infestation.

Shape shifters:

The mimic octopus is a small harmless octopus that lives on the exposed shallow sandy bottoms of river mouths. To avoid its many predators it has developed an amazing strategy: it pretends to be something else, morphing its body into new shapes, like the shape of a deadly lion-fish, a poisonous flatfish, a venomous banded sea-snake, or any number of other animals that live in the area. Not only does the mimic octopus change its shape, it also changes its behavior to match its “costume” to convincingly fool predators. Most cephalopods, which include octopuses, are well-known for their ability to change the color, pattern and texture of their skin to blend in with rocks, coral and plants. Furthermore, octopuses do not have rigid skeletal elements, which allows their bodies great flexibility in the forms they imitate. But this ability to change both physical appearance and behavior to switch back and forth among imitations of multiple species is unique to this astounding shape shifter.

Saturday, October 5, 2019

It Feels Good When You Sing a Song (In Fall)

A repost of an original article published October 3, 2012.

Most male songbirds will sing when they see a pretty female during the breeding season. But some male songbirds sing even when it’s not the breeding season. Why do so many birds sing in fall at all?

Maybe singing feels good… But how do you ask a bird if it feels good to sing? European starlings are one of those bird species that sing both in spring (the breeding season) and in fall (not the breeding season). Lauren Riters, Cindi Kelm-Nelson, and Sharon Stevenson at the University of Wisconsin at Madison did a series of ingenious experiments to ask starlings if and when it feels good to sing.

A European starling sings his fall-blues away. Photo by Linda Tanner at Wikimedia.

Psychologists have long used a paradigm called conditioned place preference (CPP) to evaluate whether an animal finds something rewarding or pleasurable. CPP is based on the idea that if an animal experiences something meaningless while at the same time experiencing something else that is rewarding, the animal will learn to associate these two things with each other in a phenomenon called conditioning. For example, a puppy that has learned that every time it sits it gets a treat, will find itself sitting more often.

A researcher can also compare how rewarding different types of treats are. If we want to know if puppies like carrots or steak better, we can give one group of puppies a carrot every time they sit and another group of puppies a piece of steak every time they sit. If the group of puppies that are conditioned with steak spend more time sitting, we can conclude that steak is more rewarding to puppies than carrots are.

Lauren and Sharon used this principle to ask starlings if singing is rewarding. They put spring starlings in a cage with a nestbox and a female and let them sing away, while counting how many songs they sang in 30 minutes. Then they immediately put them in another cage that was decorated with yellow materials on one side and green materials on the other, but they restricted each bird to only one of the two colored sides. This is the conditioning phase in which the bird learns to associate the colored cage with the feeling they get from singing.

The next day, they put the starlings in the yellow and green cage without restrictions so they could choose what side they wanted to hang out in. If singing is rewarding, we would expect starlings that sang a lot to spend more time on the side with the color they were placed in the day before.

Do people that sing in the car spend more time in the car?
Photo by
That didn’t happen. The spring starlings spent the same amount of time in the yellow or green side of the cage regardless of how much they sang the day before.

But when Lauren and Sharon did the same test with fall starlings singing without a female, there has a huge effect: Males that sang more spent much more time on the colored side of the cage they were placed in the day before. Singing, for a male starling, is apparently rewarding in fall, but not in spring.

This result actually makes a lot of sense. In spring, males sing to attract and court females, so they are rewarded by the feeling they get from the female’s response, not from the act of singing itself. But in fall, males are not attracting females. So why do they sing in fall? Because it feels good.

It looks like Sesame Street got it right with their 1970s song “It Feels Good When You Sing a Song”:

You can't go wrong
when you're singing a song
Sing it loud, sing it strong
It feels good when you sing a song

But why does singing feel good? At least some of the reason, it seems, is opioids. Not quite what Sesame Street had in mind, but hey.

Despite their reputation for being one of the world’s oldest drugs, many opioids are naturally occurring neuropeptides (brain chemicals). They are involved in pain relief and euphoria, commonly combined in the phenomenon of runner’s high. Could opioids be involved in the feel-good sensation created by singing? Maybe.

Cindi, Sharon and Lauren suspect that singing in fall causes male starlings to release opioids in their little brains, which makes singing more rewarding and makes them want to sing more. But how do we know how much opioid an animal has in its brain? Hmmm… Opioids cause analgesia (pain relief). Therefore, if singing a lot in fall releases more opioids, then birds that sing a lot in fall should be more pain-tolerant, right? The researchers let male starlings sing and counted how many songs they produced for 20 minutes. Then they dipped their foot in uncomfortably warm water and timed how long it took for the bird to pull its toes out. Fall males that sang more took longer to pull their feet out of the birdy foot-spa than did the males that sang less.

Interestingly, if you give starlings a drug to enhance opioids, they leave their feet in the foot-spa longer than if you give them a drug to block opioids. So it seems that singing in fall increases pain tolerance in the same way that opioids do, likely because the act of singing in fall causes the brain to release its own opioids. (Although it is also possible that birds that produce more opioids feel like singing more).

And what about singing in spring? When Cindi, Sharon and Lauren repeated the study with spring starlings, these birds did not get pain relief from singing. Again, they are probably rewarded by their interactions with females and not the act of singing.

So if you ever find yourself in pain, just
Sing a song
Make it simple
To last your whole life long
Don't worry that it's not good enough
For anyone else to hear
Sing a song
La la la la la la la la la la la
La la la la la la la

Want to know more? Check these out:

1. Riters LV, & Stevenson SA (2012). Reward and vocal production: song-associated place preference in songbirds. Physiology & Behavior, 106 (2), 87-94 PMID: 22285212

2. Kelm-Nelson, C.A., Stevenson, S.A., & Riters, L.V. (2012). Context-dependent links between song production 1 and opioid-mediated analgesia in male European starlings (Sturnus vulgaris) PLOS One, 7 (10)

3. Riters LV, Schroeder MB, Auger CJ, Eens M, Pinxten R, & Ball GF (2005). Evidence for opioid involvement in the regulation of song production in male European starlings (Sturnus vulgaris). Behavioral neuroscience, 119 (1), 245-55 PMID: 15727529

4. Kelm CA, Forbes-Lorman RM, Auger CJ, & Riters LV (2011). Mu-opioid receptor densities are depleted in regions implicated in agonistic and sexual behavior in male European starlings (Sturnus vulgaris) defending nest sites and courting females. Behavioural brain research, 219 (1), 15-22 PMID: 21147175

Sunday, September 29, 2019

A Yawn & Man’s Best Friend

By Erin Gellings

There’s nothing quite like the feeling of coming home after a long hard day and being welcomed by your dog. Many things dogs do are in response to their owners’ actions, including comforting and mimicking actions like yawning. There are many theories about why humans and other animals yawn, but no one theory has been proven 100% correct. What causes dogs to yawn in response to seeing a human yawn though?

Yawning Dog. Image by Scientre from Wikimedia Commons

This was the question Silvia Karine and Bessa Joana from the Universidade do Porto in Portugal set out to examine. The researchers found preliminary evidence that simply the sound of a human yawn and their relationship with their owner is enough to make a dog yawn.

Sometimes, when dogs are under stress, they can do something called a ‘tension yawn.’ There is still little evidence that explains why dogs yawn when experiencing stress. The best way to know if a dog is yawning due to feeling stressed, or in response to a human is to look at the environment. If the dog is in a new setting with new people, it is likely yawning due to stress. Researchers were very careful to make sure all the yawns dogs produced were genuine and not stress related. This was partly achieved by allowing dogs to become used to researchers before being introduced to audio of yawns. They made this determination by carefully reviewing what events led up to the dog’s yawn.

Karine and Joana used 29 dogs of various breeds and let each one become acclimated to them by just sitting in the dog’s home for about 10 minutes before they started the experiment. The researchers then exposed them to four conditions: a prerecorded sound of their owner’s yawn, familiar control sounds from their home, a stranger’s yawn, or control sounds not from their home. Each dog experienced the prerecorded sounds in a random order during two different sessions. A researcher played the sounds through a large set of speakers from audio files from a laptop in the dog’s home. The researcher wrote down every time the dog yawned, and also made a video recording of the dogs listening to the sounds so other researchers could go back and double check that their count was correct.

Twelve of the twenty-nine dogs yawned during the experiment. Out of the dogs who yawned, more dogs yawned at the yawning audio than at the background audio. This leads us to believe that the sounds of yawning are contagious and the dogs “caught” the yawn. The researchers also found that dogs yawned more when listening to the yawn of their owners than of strangers.

Aside from showing that dogs tend to yawn after hearing a human yawn, this research also hints that there may be some sort of social variable in why dogs yawn more at their owner’s yawn. The researchers suggest this may be related to a sense of empathy dogs feel towards humans, but this claim needs more research in order to be demonstrated. This research also showed that dogs do not necessarily need a visual cue of seeing a person yawn in order to yawn on their own. This is a claim that is unique to this particular project. While this research is still in its early stages, it does give us a new perspective on why dogs may yawn when around humans, and what leads to this unique behavior.

Although this study does not help us understand the function of yawning in dogs, it does bring us closer to understanding why dogs yawn in response to humans and sets the stage for future research in the field. So, after your next long day when you sit down and yawn and notice your dog yawn too, take a moment to appreciate the connection they have with you.


Finlay, K. (2017, June 15). Why do dogs yawn? American Kennel Club.

Silva, K., Bessa, J., & De Sousa, L. (2012). Auditory contagious yawning in domestic dogs (Canis familiaris): First evidence for social modulation. Animal Cognition, 15(4), 721-724.

Why do I yawn? (2019).

Saturday, September 21, 2019

A Master of Disguise (A Guest Post)

By Jake Klemm

Cephalopods are among the most intelligent of marine life. Their highly advanced nervous systems allow them to exhibit a complex array of behaviors (for example, camouflage). Within this array is a rather unique behavior observed in the cuttlefish Sepia pharaonis. These elegant beings are now known to… intensely flap their arms? These animals are truly graceful.

A lovely photo of S. pharaonis. Image by Silke Baron at Wikimedia Commons.

Researchers Kohei Okamoto, Haruhiko Yasumuro, Akira Mori, and Yuzuru Ikeda of the University of the Ryukyus in Okinawa, Japan observed this behavior on two separate occasions while studying S. pharaonis. The scientists had initially collected these cuttlefish with the intention of conducting other experiments but noticed this behavior while the cuttlefish were introduced to a large water-filled tank and while hunting prey. After noticing this wild arm-flapping behavior, the researchers turned their attention towards why the behavior was being displayed.

The researchers first observed this behavior in December of 2011. The cuttlefish were placed in a large, circular tank for conducting other experiments when a couple of them were observed to flap their arms. After the initial experiments were finished, a few of the cuttlefish were placed in the same sized tank and observations were recorded with a video camera over a period of five days. This behavior was revisited in 2013 for further observation. The cuttlefish they used were reared from eggs found in the same coastal waters of Okinawajima Island as the cuttlefish that were part of the 2011 experiments. Again, cuttlefish were placed in a large tank to observe the behavior with a video camera. The researchers counted each occurrence of the behavior and recorded the duration of each behavior. After observations were complete, the researchers performed experiments to observe the hunting ability of S. pharaonis. This arm-flapping behavior was observed unexpectedly while the cuttlefish hunted prey. The means of recording the behavior were the same as described above. In addition, the researchers recorded the number of prey caught between cuttlefish that did and did not display the behavior.

The researchers noticed variation in the frequency and duration of this behavior in the presence and absence of prey. When placed in a tank without prey, only a small number of cuttlefishes displayed this behavior. Of the cuttlefish that did flap their arms, the behavior lasted (on average) no longer than 37 seconds. However, the cuttlefish that were placed in a tank with prey, the behavior was displayed for at significantly longer period of time. In addition to that, more cuttlefish overall were seen flapping their arms in this second experiment. The cuttlefish that flapped their arms caught a significantly larger number of fish than the ones that did not flap their arms, despite being observed in the same tank and having access to the same number of prey animals. This observation led the researchers to believe that something about this unique behavior is helping the cuttlefish capture more prey.

A front view of a cuttlefish. Image by Stickpen at Wikimedia Commons.

The resemblance is uncanny! Image by Maximilian Paradiz at Wikimedia Commons.

What could this all mean? The researchers think that the cuttlefish may be mimicking another organism, specifically the hermit crab, to confuse the prey fish into thinking that they are another harmless animal. It is thought that the head of the cuttlefish resembles the shell of the hermit crab while the arms resemble the eyes and legs of the hermit crab. Posing as a harmless crab would allow the cuttlefish to get behind enemy lines and ultimately catch more prey. Further research will have to be done in lab as well as the field to see if this behavior is really that of mimicry. Other cephalopods are notorious for mimicking other animals, so it is not out of the realm of possibility. Studying this behavior would allow scientists to difurtveher into the evolutionary history of S. pharaonis. Until then, the graceful limb-flailing will remain an ever-tantalizing mystery.


Okamoto, K., Yasumuro, H., Mori, A., & Ikeda, Y., (2017). Unique arm-flapping behavior of the pharaoh cuttlefish, Sepia pharaonic: putative mimicry of a hermit crab. Journal of Ethology, 35(3), 307-311. DOI: 10.1007/s10164-017-0519-7

Saturday, September 14, 2019

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

Do you dream about a career of studying animals?
Image by
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.

Sunday, September 8, 2019

Tiny Ninjas, Big Bites (A Guest Post)

By Alexis Brauner

Venom isn’t just a weapon for snakes and spiders.

A smaller, more dangerous insect is in existence and falls into the realm of venomous creatures: the assassin bug. This little critter is part of a scientific family called Reduviidae, a group where all the members share the same characteristic of being an ambush predatory bug. They prey on invertebrates (animals that don’t have a spine), such as crickets and mealworms, by injecting venom into them.

An assasin bug. Source: Fir0002/Flagstaffotos at Wikimedia Commons.

Assassin bugs are believed to have two versions of venom – one for feeding and one for defense. Both types of venom are made up of more than 100 proteins, but what is unique about it is its ability to paralyze and liquify the inside of the prey. That’s right… liquify. The tissues of the prey turn into a jello-like substance that the assassin bug can then suck through a long tube on its mouth called the proboscis.

How is the venom able to do that?

First, let’s peek at the mechanisms that work to carry the venom through the body of the assassin bug and into its meal.

The venom apparatus of an assassin bug is made up of three main parts: secretory glands, a muscle-driven pump, and a venom channel. The three secretory glands (the anterior main gland, posterior main gland, and accessory gland) are in the thorax and abdomen of the assassin bug. These separate glands release a specific form of assassin bug venom depending on what situation the bug is facing. For example, the anterior main gland releases a form of venom that does not paralyze prey but is thought to be used as a defense mechanism, while the posterior main gland releases the deadly form of venom.

The venom apparatus of an assassin bug. Source: Walker, et. al, 2018, modified by Alexis Brauner

Once released, the venom then makes its way to a muscle-driven pump within the head of the bug. The pump fills with the available venom when the muscle contracts and is released once the muscle relaxes. Think of the venom pump as a clothes pin: when you push on the prongs, the pin opens, and you can put things in it to hold; once you let go of the prongs, the mouth of the pin closes, but now the prong end is open. In this example, your fingers are the muscle and the clothes pin is the pump with one end open at a time. The muscle relaxation releases the venom into the venom channel in the interlocking maxillary stylets (also known as the fangs) of the assassin bug. And then…


Venom is in the food or the foe.

And if it’s in the food, then the tissues of the prey turn into liquid. This liquification phenomenon is caused by enzymes in assassin bug venom called proteases. All enzymes catalyze, or speed up, chemical reactions; however, proteases are specialized enzymes that catalyze the destruction of proteins. This means that the assassin bug venom goes into the prey and the proteases are like Pac-Men with razor sharp teeth that grind up the primarily protein tissue at such a lightning fast speed that, within seconds, the prey is juice!

Scientists continue to research assassin bug venom to learn more about its components, but one thing is for sure: The extraordinary liquid weapon housed in such a small insect is why assassin bugs are tiny ninjas with big bites.

To learn more:

Walker, A., Madio, B., Jin, J., Undheim, E., Fry, B., King, G. (2017). Melt With This Kiss: Paralyzing and Liquefying Venom of The Assassin Bug Pristhesancus plagipennis (Hemiptera: Reduviidae). Mol Cell Proteomics, 16 (4), 552-566. DOI: 10.1074/mcp.M116.063321.

Walker, A., Mayhew, M., Jin, J., Herzig, V., Undheim, E., Sombke, A., Fry, B., Meritt, D., King, F. (2018). The assassin bug Pristhesancus plagipennis produces two distinct venoms in separate gland lumens. Nat Commun, 9, 755. DOI: 10.1038/s41467-018-03091-5

Friday, August 30, 2019

A Tiny Surprise in Regards to Regeneration (A Guest Post)

A reposting of an original article by Jessica Klein in The Scorpion and the Frog.

The ability to regenerate limbs and tails is nothing new to reptiles and amphibians. Many lizards are able to drop their tails to escape an enemy, whereas salamanders have been known to grow back entire legs with muscle after being attacked by a predator. These regenerative characteristics have been seen to some extent in rabbits and pika before 2012, but were later discovered to occur extensively in, surprisingly enough, small African spiny mice.

One of the African spiny mouse species. Photo by Ashley Seifert and Tom Gawriluk.

In a study done by Ashley W. Seifert and Megan G. Seifert at the University of Kentucky, Todd M. Palmer and Malcolm Maden at the University of Florida, Stephen G. Kiama at the University of Nairobi, and Jacob R. Goheen at the University of Wyoming, African spiny mice were studied in order to view the extent of their regenerative properties, why they might occur, and the physiological processes that make it happen.

The rodents were captured in Kenya, where researchers learned that vigorous movement during handling caused the skin of African spiny mice to come apart. One mouse was reported to have an open wound that took up 60% of its back, just from being handled! Therefore, Dr. Seifert measured the amount of strength it took to tear the skin of spiny mice using something called a Hounsfield tensometer. He took the measurements from that tool and graphed them on a plot, creating something called a stress-strain curve which showed how much strength it took to tear the skin of the mouse.

The strength measurements revealed that the skin of these species was 77 times weaker than average mice, explaining why their skin tore so easily during the handling process. In order for the African spiny mice to survive such large injuries due to their extremely fragile skin, it would be beneficial to heal quickly or regenerate the skin. This is exactly what Dr. Seifert discovered.

An African spiny mouse shows
the regenerative process with
(1) being before the wound
(2) being after the wound and
(3) showing how the wound was
completely healed after 30 days.
Figure from Seifert, et al., 2012.
After the strength measurements were completed, the rodents were anaesthetized and had 4mm and 1.5cm wounds made on their skin, as well as 4mm holes punched in their ears in order to view the regeneration process. In an average rodent, the repair of a 4mm skin wound takes around 5 to 7 days and is accompanied by a significant amount of scarring. However, in the African spiny mouse it only took 1 to 2 days for scabbing of the skin wound to occur with new cells forming on the outside of the wound to repair it. After just 10 days, the ear of the mouse was fully healed. In the ear punches, there were no signs of scarring that would have been expected in a rodent, and healthy cartilage had formed. By the 21st day of the experiment, African spiny mice had developed new hair follicles and healthy new hair covering the once wounded area. In total, Dr. Seifert discovered that African spiny mice were capable of regenerating their skin, hair follicles, and sweat glands.

Dr. Seifert suggested the skin of African spiny mice is fragile because it allows them to escape predators. This would require a quick healing time to reduce the chance of infection and ultimately death in the mouse after escaping. This is why they may have gained the ability to regenerate their skin, but how exactly does this happen? Dr. Seifert and his research team recently showed that, in these species, it occurs through a process known as epimorphic regeneration. This is when a blastema (a mass of immature, unspecialized cells) forms where the wound once was. These cells are capable of turning into whatever type of tissue was present in that area. This particular method of regeneration is how salamanders are capable of regenerating their limbs. Again, more research would need to be done in order to confirm or deny this. However, one thing is true, and that is that more research into this could prove to be useful in the future of medicine when it comes to healing critical and invasive injuries. By discovering the physiological process behind this, and then being able to replicate it in a lab, researchers may discover ways to heal injuries faster.

Works Cited

Seifert, Ashley W., Stephen G. Kiama, Megan G. Seifert, Jacob R. Goheen, Todd M. Palmer, and Malcolm Maden. "Skin Shedding and Tissue Regeneration in African Spiny Mice (Acomys)." Nature 489 (2012): 561-65. doi:10.1038/nature11499

Gawriluk, Thomas R., Jennifer Simkin, Katherine L. Thompson, Shishir K. Biswas, Zak Clare-Salzler, John M. Kimani, Stephen G. Kiama, Jeramiah J. Smith, Vanessa O. Ezenwa & Ashley W. Seifert. "Comparative analysis of ear-hole closure identifies epimorphic regeneration as a discrete trait in mammals" Nature Communications 7.11164 (2016). doi:10.1038/ncomms11164

Tuesday, April 16, 2019

Does Social Status Change Brains?

A reposting of an original article in The Scorpion and the Frog.

Photo by The Grappling Source Inc.
at Wikimedia Commons
Being subordinated is stressful. The process of one individual lowering the social rank of another often involves physical aggression, aggressive displays, and exclusion. In addition to the obvious possible costs of being subordinated (like getting beat up), subordinated individuals often undergo physiological changes to their hormonal systems and brains. Sounds pretty scary, doesn’t it? But what if some of those changes are beneficial in some ways?

Dominance hierarchies are a fact of life across the animal kingdom. In a social group, everyone can’t be dominant (otherwise, life would always be like an episode of Celebrity Apprentice, and what could possibly be more stressful than that?). Living in a social group is more peaceful and nutritive when a clear dominance hierarchy is established.

Establishing that hierarchy often involves a relatively short aggressive phase of jostling for position, followed by a longer more stable phase once everyone knows where they fall in the social group. Established dominance hierarchies are not always stable (they can change over time or from moment to moment) and they are not always linear (for example, Ben can be dominant over Chris, who is dominant over David, who is dominant over Ben). But they do generally help reduce conflict and the risk of physical injury overall.

Nonetheless, it can be stressful to be on the subordinate end of a dominance hierarchy and these social interactions are known to cause physiological changes. Researchers Christina Sørensen and Göran Nilsson from the University of Oslo, Cliff Summers from the University of South Dakota and Øyvind Øverli from the Norwegian University of Life Sciences investigated some of these physiological differences among isolated, dominant, and subordinate rainbow trout.

A photo of a rainbow trout by Ken Hammond at the USDA.
Photo at Wikimedia Commons.
Like other salmonid fish, rainbow trout are aggressive, territorial and develop social hierarchies as juveniles. Dominant trout tend to initiate most of the aggressive acts, hog food resources, grow larger, and reproduce the most, whereas subordinate trout display less aggression, feeding, growth, and reproduction. The researchers recorded the behavior, feeding and growth rates in three groups of fish: trout housed alone, trout housed with a more subordinate trout, and trout housed with a more dominant trout. The researchers also measured cortisol (a hormone involved in stress responses), serotonin (a neurotransmitter involved in mood, the perception of food availability, and the perception of social rank, among other things) and the development of new neurons (called neurogenesis) in these same fish.

This video of two juvenile rainbow trout was taken by Dr. Erik Höglund. Here is Christina Sørensen’s description of the video: “What you see in the film is two juvenile rainbow trout who have been housed on each side of a dividing wall in a small aquarium. The dividing wall has been removed (for the first time) immediately before filming. You will see that the fish initially show interest for each other, followed by a typical display behaviour, where they circle each other. Finally one of the fish will initiate aggression by biting the other. First the aggression is bidirectional, as they fight for dominance, but after a while, one of the fish withdraws from further aggression and shows only submissive behaviour (escaping from the dominant and in the long run trying to hide... and as is described in the paper, depressed feed intake). The video has been cut to show in quick succession these four stages of development of the dominance hierarchy”.

The researchers found that as expected, the dominant trout were aggressive when a pair was first placed together, but the aggression subsided after about 3 days. Also as expected, the dominant and isolated trout were bold feeders with low cortisol levels and high growth rates, whereas the subordinate trout did not feed as well, had high cortisol levels and low growth rates. Additionally, the subordinate trout had higher serotonin activity levels and less neurogenesis than the dominant or isolated trout. These results suggest that the subordination experience causes significant changes to trout brain development (Although we can’t rule out the possibility that fish with more serotonin and less neurogenesis are predisposed to be subordinate). In either case, this sounds like bad news for subordinate brains, right? Maybe it is. Or maybe the decrease in neurogenesis just reflects the decrease in overall growth rates (smaller bodies need smaller brains). Or maybe something about the development of these subordinate brains improves the chances that these individuals will survive and reproduce in their subordination.

A crayfish raising its claws. Image by Duloup at Wikimedia.
Research on dominance in crayfish by Fadi Issa, Joanne Drummond, and Don Edwards at Georgia State University and Daniel Cattaert at the University of Bordeaux helps shed light on this third possibility. Crayfish (which are actually not fish at all, but are freshwater crustaceans that look like small lobsters) form long-lasting and stable social hierarchies. If you poke a crayfish in the side, an isolated or dominant crayfish will turn towards whatever poked it and raise its posture and claws to confront it; A subordinate crayfish will do one of two maneuvers that involves lowering the posture and backing away from whatever poked it. Furthermore, dominant and subordinate crayfish have different neuronal activity patterns in response to being poked, and part of this difference involves differences in the activity of serotonergic neurons.

It appears that the brains of dominant and subordinate individuals function differently and part of this difference involves serotonin. This may help dominant animals to continue to behave in a dominant fashion and subordinate individuals to continue to behave in a subordinate fashion, thereby preserving the peace for the whole social group.

Want to know more? Check these out:

1. Sørensen, C., Nilsson, G., Summers, C., & Øverli, �. (2012). Social stress reduces forebrain cell proliferation in rainbow trout (Oncorhynchus mykiss) Behavioural Brain Research, 227 (2), 311-318 DOI: 10.1016/j.bbr.2011.01.041

2. Issa, F., Drummond, J., Cattaert, D., & Edwards, D. (2012). Neural Circuit Reconfiguration by Social Status Journal of Neuroscience, 32 (16), 5638-5645 DOI: 10.1523/JNEUROSCI.5668-11.2012

3. Yeh, S., Fricke, R., & Edwards, D. (1996). The Effect of Social Experience on Serotonergic Modulation of the Escape Circuit of Crayfish Science, 271 (5247), 366-369 DOI: 10.1126/science.271.5247.366

4. Issa, F., & Edwards, D. (2006). Ritualized Submission and the Reduction of Aggression in an Invertebrate Current Biology, 16 (22), 2217-2221 DOI: 10.1016/j.cub.2006.08.065

Tuesday, April 9, 2019

What To Do If You Find Orphaned Wildlife

A repost of an original article from The Scorpion and the Frog.

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 2, 2019

5 Animal Species With Surprising Memories

A repost of an original article from The Scorpion and the Frog.

We often think of animals as having hilariously short memories – the “memory of a goldfish”, if you will. But many animals have memories that can put yours to shame.

There are many different kinds of memory and each of them is controlled differently by different parts of the brain. Short-term memory can be thought of as the brain’s scratch pad: It holds a small amount of information for a short period of time while your brain decides whether it is worth retaining in long-term memory or if it can just fade away. When a short-term memory becomes a long-term memory, this process is called consolidation and involves physiological changes in the brain.

Long-term memory can be further divided into two main types: procedural memory and declarative memory. Procedural memory is used to remember how to do things and what objects are needed to do those things. Declarative memory is used for recall and can be further divided into memory used to recall facts (semantic memory) and events (episodic memory).Each of these different types of memories are stored in different parts of the brain. Furthermore, different types of facts (remembering faces versus numbers, for example) and different types of events (depending on if they have an emotional component or not, for example) are also stored in the brain differently. Because species differ in how we rely on our brains, it makes sense that this might be reflected in our abilities to remember in different ways.

So let’s check out some of the most amazing memories in the animal kingdom:

Do you know what all your kids and nieces and nephews are
doing right now? These elephants do. Photo by PJ KAPDostie
at Wikimedia.
1) They say an elephant never forgets. Elephants are very social animals that live in large stable herds. This has led to some incredible feats of social memory. They can keep track of the whereabouts of 30 group members at once and they can remember an animal they briefly met over 20 years ago. For an animal that lives about 50 or 60 years, this is very impressive. Elephants also have outstanding episodic memory: In 1993, Tarangire National Park in Tanzania suffered the worst drought that it had seen in 35 years. It was so severe that it killed 20% of elephant calves, compared to the average loss of about 2%. Of three herds that lived in the park in 1993, two of them were led by females that had lived during the severe droughts of 1958-61 and those herds left the park and were more successful at finding food and water. The herd that stayed was led by a younger female that had never experienced such a severe drought and that herd suffered 63% of the total mortality.

Dolphins never forget a name. Photo from the
NOAA Photo Library available at Wikimedia.
2) Bottlenose dolphins have even more incredible social memories. They, like elephants, live in complex social groups. Each dolphin has a unique whistle that it uses like a name. When they are played recordings of whistles of companions they lived with years or even decades earlier, they approach the speakers for longer than when they are played the whistles of dolphins they never met. The fact that they, like elephants, remember companions for over 20 years is much more impressive because their lifespan is only 40-50 years!

Sea lions can remember
meaningless tricks for years.
Photo by LSA2886 at Wikimedia.
3) Sea lions have amazing procedural memory. In 1991, marine biologists at the University of California, Santa Cruz, taught a California sea lion named Rio a card trick. They held up one card with a letter or number on it and another set of two cards: one that matched the first card and one that did not. Rio learned to pick the matching card to be rewarded with a fish. Everyone was impressed and she didn't do the trick again... until 10 years later, when researchers pulled out the cards and asked her to do it again. Rio had the same score in 2001 with no practice that she did in 1991 when she originally learned the trick!

Clark's nutcrackers can remember where they stashed
30,000 pine nuts.I can't even keep track of my keys.
Photo by Gunnsteinn Jonsson at Wikimedia.
4) Clark’s nutcrackers can remember the exact location of 30,000 pine nuts. This kind of superhero ability is born out of necessity: nutcrackers completely rely on their caches of food to get them through the winter. However, despite their amazing long-term spatial memory, their short-term memory is below average: they can’t even remember the color of a light for 30 seconds.

5) Chimpanzees can put your working memory to shame. Working memory is a form of short-term memory that is applied to a task. A group of researchers taught chimpanzees to do a task in which they were shown the numbers from 1-9 in random locations on a computer screen. When the numbers are covered, chimps can remember where each number was. Furthermore, they only need to see these randomly placed number for a few seconds to get this task correct. In comparison, only people that are considered savants have comparable abilities.

Tuesday, March 26, 2019

Interrupting Insects

A reposting of an original article from The Scorpion and the Frog.

What do you think of when I say “communicate”? Most likely, you are imagining people communicating by an auditory mode (talking and listening, making expressive sounds) or by a visual mode (observing body language, reading and writing). As a species, humans inherently rely heavily on our hearing and vision to perceive the world around us and so it makes sense that we communicate with one another using these modalities. But animal species are incredibly diverse in their means of perceiving their worlds and their modes of communication. Because we have been so focused on studying animal signals that we can perceive, we have only recently begun to more actively explore animal communication in these other modes. One of these modes is soundless surface vibrations.

The photo is of an adult Tylopelta gibbera on a host plant stem
(photo (c) Rex Cocroft).
Despite the fact that we do not perceive most animal surface vibration signals around us, vibrational communication is very common, especially among insects and spiders. Rex Cocroft at the University of Missouri at Columbia and Rafa Rodríguez at the University of Wisconsin at Milwaukee point out in a review of vibrational communication that over 195,000 species of insects communicate using soundless surface vibrations. We can experience many of these substrate vibration signals by broadcasting them through a speaker as an airborne vibration (which we perceive as sound).

Vibrational signals serve a number of functions in the insect worlds. Social insects, like ants, termites, and bees, often use vibrational signals to coordinate foraging. Groups of juvenile thornbug treehoppers vibrate when a predator approaches, calling in the mother to defend them. Males of many species have been found to use vibrational signals to attract females and the females often use these signals to choose a mate.

Vibrational signals are carried through a solid substrate, so they can only travel as far as the substrate is continuous and they are affected by attributes of the substrate (like changes in density). Because of these constraints, most vibrational signals can only travel about the length of a human arm. Many insects that use vibrational communication live on host plants, and it is these host plants that transmit the vibration signals. These animals face many challenges in transmitting their signals to the intended recipient. For example, wind, rain, and environmental sounds can create competing vibrations (background noise). In addition to environmental background noise, the vibrational soundscape of a given plant stem will likely include many signaling individuals, often of many species. Not only are there difficulties in getting your signal to your intended audience, but there are also risks of eavesdropping predators and competitors.

Frédéric Legendre, Peter Marting and Rex Cocroft at the University of Missouri at Columbia, demonstrate the social complexities of vibrational communication in a new study of competitive signaling in a treehopper species, Tylopelta gibbera. Tylopelta gibbera is a small treehopper in the southern United States, Mexico and Guatemala, that only lives on plants from the Desmodium genus. Males will attract and court females with vibrational signals and interested females will respond to the male with vibrational signals of their own. However, many individuals can often be found on a single plant and if two signaling males are present, the receptive female will typically respond to both of them and only mate with one (generally the first one she encounters). What is a competing male to do?

Listen to a male Tylopelta gibbera advertisement signal here.

The researchers performed a series of experiments, in which they observed treehoppers on potted host plants in the lab. With this set-up, they could control the environmental conditions, decide the number of males and females on the plant, record vibrational signals and play them back. They found that once a male signals and detects a female response, he will actively search for her along the plant, alternating signals and steps in a “Marco Polo” mating game until he finds her. Males found the females almost twice as fast if they were the only male on the plant, indicating that the presence of a second male on the plant somehow interferes with their ability to locate the female. Also, when two males were on the plant, they produced a new signal type that was never produced by a lone male on a plant. Males that had no male competition only produced signals that had a whine sound, followed by a series of pulses (and the female would then immediately respond with a harmonic sound of her own). This male signal is called the advertisement signal. Males that had a competing male on the plant would produce an additional signal that was a short tonal note. Interestingly, these males often produced this second signal at the same time that their competitor was advertising himself. Hmmm… could this be a masking signal used to interrupt the competitor? How could you figure that out?

This figure from Legendre, Marting and Cocroft's 2012 Animal Behaviour paper shows
the whine and pulses of a male advertisement signal (top) and a histogram of when the
masking signal occurs in relation to the timing of the advertisement signal (bottom).
First, the researchers asked, “When do males produce this second signal?” The researchers put two males on a plant with one female and recorded their vibrations. They found that in this situation, males typically produced this second signal while his competitor was just beginning the pulse section of his advertisement signal. Next, the researchers played back recordings of male advertisement signals followed by female responses to a lone male on a plant. All of the males tested produced the masking signal during the pulse section of the male advertisement signal on the recording.

Don't you hate it when someone does this?

Next, the researchers asked, “How do females respond to this second signal?” On plants with one female and two males, females didn’t respond as much to advertisement signals overlapped by a second signal as they did to advertisement signals alone. The researchers then played recordings of male advertisement signals to lone females on the plants. Females responded significantly more often if the advertisement signal was not overlapped by a masking signal.

So, male treehoppers get an edge up on getting the girl by interrupting the other competing males. Sneaky buggers!

Want to know more? Check these out:

1. COCROFT, R., & RODRÍGUEZ, R. (2005). The Behavioral Ecology of Insect Vibrational Communication BioScience, 55 (4) DOI: 10.1641/0006-3568(2005)055[0323:TBEOIV]2.0.CO;2

2. Legendre, F., Marting, P., & Cocroft, R. (2012). Competitive masking of vibrational signals during mate searching in a treehopper Animal Behaviour, 83 (2), 361-368 DOI: 10.1016/j.anbehav.2011.11.003

3. A Japanese research team has harnessed this phenomenon to create a remote-control that makes annoying people stop talking. Find out more at the blog Gaines on Brains!