Male Black Widows Sniff Out Femme Fatales

I am thrilled to announce that this month I am joining a new top-notch science blogging team at Scitable, Nature Education’s award-winning science education website! (But don’t worry, friends. I will continue to post here about animal physiology and behavior every Wednesday). Next week, Scitable will be launching eleven new blogs covering topics like neuroscience, genetics, oceanography, physics and more. I will be co-authoring an evolution blog called Accumulating Glitches together with Sedeer el-Showk (the author of the fantastic nature blog Inspiring Science). To celebrate the launch of these new science blogs, many of us are writing guest posts at Student Voices, another Scitable blog. What follows is the start of my guest post:

__

A female western black widow contemplates the tastiness
of her suitor. Photo by Davefoc at Wikimedia Commons.

Sexual reproduction is a costly affair, but the costs are not usually equal for males and females. Among animals, females generally produce larger gametes (eggs are way bigger than sperm), spend more energy gestating or incubating the young before they are born, and spend more effort caring for the young after they are born. It’s no wonder then that across animal species, females are typically more choosy of who they mate with than males are.

But what if the tables are turned and sex is more costly for males than it is for females? Such is often the case for black widow spiders, named for the females’ infamous reputation for making a post-coital snack of their mates. In such a situation where every sexual encounter is potentially the last, who would blame males for being more choosy of their mating partners? But are they?

To find out, read the rest of the post here!

And to find out more, check this out:

Johnson, J., Trubl, P., Blackmore, V., & Miles, L. (2011). Male black widows court well-fed females more than starved females: silken cues indicate sexual cannibalism risk Animal Behaviour, 82 (2), 383-390 DOI: 10.1016/j.anbehav.2011.05.018

Thanks Mom!

Like Mother, like baby!
Photo from freedigitalphotos.net.

Moms give us so much more than we ever give them credit for. Biologically speaking, we all have a mom and a dad (unless you’re a flatworm or some other species that can reproduce without sex) that provide us with one of each chromosome type (our chromosomes contain our genes, commonly thought of as our “biological blueprints”). So it makes sense that we tend to think of ourselves as being half-our-mom and half-our-dad. But not so! All of us are slightly more-our-mom and slightly less-our dad.

Our genes are encoded in our DNA, which is coiled and tightly packed into dense little chromosomes. Most of our cells contain 23 different pairs of chromosomes (for a total of 46), and one from each pair comes from each parent. One of those pairs is the sex chromosomes. Individuals with two X sex chromosomes are genetically females and individuals with an X and a Y sex chromosome are genetically male. Because genetic males are the only ones with Y chromosomes, all Y chromosomes are inherited from dad. But compared to X chromosomes, Y chromosomes are piddly little things that don’t contain as many genes. So if you’re a guy, you already have more genes from mom than from dad.

In addition to our 46 chromosomes that we keep in the nucleus of each cell, we also have a tiny set of genes in another cell structure, the mitochondria. This mitochondrial DNA is only inherited from the mother, so regardless of whether you are XX or XY, you have a few more genes from mom than from dad.

Wait! My genes are where??
Your genes are lined up on the doubled-stranded DNA, which is tightly coiled and packed into
chromosomes. You have 23 different pairs of chromosomes, where one of each pair came from
mom and the other came from dad. A copy of each of these 23 pairs of chromosomes
(46 chromosomes in total) is in the nucleus of every cell you have (except for sperm or egg cells,
which only have one of each pair, or 23 chromosomes in total). Get it?
Figure adapted from an image by KES47 at Wikimedia.

But we are not simply a product of our genes. If we were, identical twins would be, well… identical. But they’re not. The slight differences between twins results from differences in how our environment interacts with our genes. (By environment, I’m not just talking about temperature and air quality, but rather all external influences). Our environment plays a big role in shaping the individuals we become, and our mothers have more effect on our environment than our fathers do. When we are developing in the womb, our moms’ bodies single-handedly provide us with nutrients, hormones, and antibodies (and sometimes pathogens). During this time, her circumstances and decisions will determine what kind of setting we are born into. After we’re born, the social interaction, nutrition, and antibodies (through breast feeding and/or vaccines) she provides will all influence our gene activity and thus how we develop. Collectively, the traits that we develop due to these factors and all mom’s other nongenetic influences are called maternal effects.

Mom gives us more genes, and has more input in determining how active each gene is. In the end, we are who we are in large part because of our moms.

So Mom, this is for you:

Happy (early) Mother’s Day!


Want to know more? Check these out:

1. BERNARDO, J. (1996). Maternal Effects in Animal Ecology Integrative and Comparative Biology, 36 (2), 83-105 DOI: 10.1093/icb/36.2.83

2. Wolf, J., & Wade, M.J. (2009). What are maternal effects (and what are they not)? Phil. Trans. R. Soc. B, 364, 1107-1115

The Craptastic Conversations of the Black Rhinoceros

What are you saying with your smells? Image by freedigitalphotos.net.

Animals communicate in all kinds of ways: with vocalizations, body language, vibrations, and even odors. In fact, compared to most species, we are pathetic in our abilities to communicate with body odor. With just a whiff of eau de crotch, many animals can decipher that individual’s species, sex, age, health status, reproductive status, emotional state, and dietary history. Some species can go so far as to make out that individual’s exact identity (*Sniff Sniff* Oh! Hi Mike!).

There are a lot of advantages to using odors to communicate. For one thing, messages sent by smell are more likely to be honest than messages sent by other means. (You might be able to do a pretty good Shakira impersonation, but you can’t hide the fact that you had a tuna sandwich for lunch and haven’t brushed your teeth since). Another advantage is that unlike other signal types, an odor signal can be left behind, kind of like those sticky-notes you leave on your food in the fridge.

How do scientists know which species use odors to communicate and what information these signals contain? This investigatory process involves a lot of reasoning.

A solitary black rhino. Photo by John and Karen Hollingsworth
at the US Fish and Wildlife Service.

Wayne Linklater, Katha Mayer and Ron Swaisgood, an international team of researchers associated with Victoria University of Wellington in New Zealand, Nelson Mandela Metropolitan University in South Africa, University of Potsdam in Germany, and the San Diego Zoo Institute for Conservation Research in California, set out to test whether black rhinoceros use odor to communicate. Although rhinos lack the specialized scent glands that many smell-communicating species have, there are many reasons to suggest that they are a likely species to communicate this way.

A photo of field assistant Brayden
Crocker with rhino dung scrape mark.
Photo by Wayne Linklater.

Black rhinos are solitary. Females often have overlapping ranges, but males’ territories only overlap at their boundaries. This means that they would rarely encounter one another and would benefit from a means to leave “sticky-notes” behind to indicate where their territories are. Furthermore, despite their poor eyesight, male black rhinos have a poop-ritual in which they scrape at the ground and spread their dung. Although female rhinos don’t spread their poo, they do spray their pee when they are ready to mate.

Between 2004 and 2006, the Ezemvelo KwaZulu-Natal Wildlife Veterinary and Game-Capture Team captured a number of black rhinoceros from the Ezemvelo KwaZulu-Natal Wildlife Reserves in South Africa in order to relocate them to other reserves for conservation purposes. At this time, Wayne, Katha, and Ron collected dung from rhinos with known sexes and ages. They stored the dung in labeled plastic bags and froze them to preserve the odor freshness for a series of experiments to explore the extent of the black rhinos’ abilities to communicate with their bodily waste.

In one experiment, the researchers asked whether black rhinos could differentiate between the dung of males and females and between the dung of adults and immature subadults. They presented rhinos with the dung of young males, young females, adult males and adult females, and then measured how many times they sniffed each and how long they spent sniffing. The rhinos spent more time sniffing male dung than female dung. This means that rhino poop likely communicates the sex of the pooper. Rhinos also responded differently to adult and subadult poop, suggesting that they can tell whether the pooper is an adult or not.

In order to test whether rhinos may be able to tell the individual identity of the pooper, they did a habituation-dishabituation test. Habituation is when an animal gets used to something that happens repeatedly and stops responding to it. For example, the first time you heard Gangnam Style, you probably stopped what you were doing and maybe even learned the dance. But now it has been so ridiculously over-played that when you hear it, you just ignore it. Dishabituation happens when an animal is exposed to something slightly different and has a heightened response again. Kind of like the excitement over Psy’s new song, Gentleman, even though it sucks.

A photo of rhino performing flehmen, a behavior that helps
waft odors for better odor detection. Photo by Wayne Linklater.

Wayne, Katha, and Ron exposed rhinos to the same individual’s dung three times to see if their interest in it waned. With each presentation, the rhinos spent a little less time sniffing it. When the researchers put poop from a different rhino (that was the same sex and age as the first pooper) in front of them, their interest returned. This suggests that rhinos can tell the individual identity of the pooper from his/her poop.

But can rhinos use their poop like “sticky-notes”? The researchers aged dung for 1, 4, 16 and 32 days and put them in front of rhinos to smell. Their response was the same, no matter how old the dung was. This indicates that rhinos can spread their poop to leave an “I was here” message for at least a month.

As fun as it may be to spend years studying rhinoceros poop, there are some important uses for research like this. Black rhinos are critically endangered, largely due to hunting, poaching and habitat loss. In fact, Mozambique's Limpopo National Park declared the last of their rhino population killed as recently as last month. Conservation efforts such as captive breeding programs and reintroductions have helped in several areas, but have not been enough to sustain the populations. Conservationists could apply this knowledge of how rhinoceros use dung odors to communicate to these breeding and reintroduction efforts in order to make them considerably more successful.


Want to know more? Check this out:

Linklater, W., Mayer, K., & Swaisgood, R. (2013). Chemical signals of age, sex and identity in black rhinoceros Animal Behaviour, 85 (3), 671-677 DOI: 10.1016/j.anbehav.2012.12.034

The Science Life

Grad school is not like anything else you will ever experience. But don’t take my word for it:

"I’m a Grad Student" by Adam Ruben:

"Grad School, I Love You, But You're Bringing Me Down" (LCD Soundsystem Parody) by Nathaniel Krefman at UC-Berkeley:

"The Lab Song" (Bruno Mars Parody) by the Cohenford Lab at Marshall University:

Vote for your favorite in the comments section below. And if you feel so inspired, make a video of your own, upload it on YouTube and send me a link to include in a future post!

Check out other sciency song battles at Science Beat, Scientist Swagger and Battle of The Grad Programs!

How To Get Into An Animal Behavior Graduate Program: Getting Research Experience

You grew up watching nature documentary scientists travelling the world, covertly following and filming wild animals, learning all the secrets of the animal world first-hand with bewildering technology, and you have thought that should be me.


This could be you! Photo by Genny Kozak.

Conducting animal behavior research is incredibly satisfying and exciting, but it is also tedious and frustrating. It’s not for everyone… So how do you know if it’s for you unless you’ve tried it? And how do you try it if you’ve never done it before?

There are plenty of ways to get involved in research, even if you have no experience. And a good place to start is wherever you are.

If you are a college student or have a university in your area, chances are pretty good that there are people on your campus doing research that you would find interesting. Those people may be professors, research scientists, postdocs or graduate students. They may be in a biology, psychology or anthropology department. And their research interests are often listed either on their individual webpages or on departmental webpages. Poke around: They’re out there.

Another good place to look is your local zoo or aquarium. Many large and renowned zoos and aquariums have official research internship programs. But even smaller zoos that don’t advertise will accept volunteers if you make them the right pitch.

If you are interested in wildlife studies, your state DNR (the Department of Natural Resources) may have an internship program as well. Even if they don’t have an official program, there is a chance that they have researchers that can be persuaded to take on a dedicated mentee.

Once you have identified people that you would potentially like to work with, you need to contact them to assess whether they have something productive for you to do and to convince them that you are the one for the job. This first contact may seem intimidating, but the reality is that any researcher would love some help from an enthusiastic, dedicated, and intelligent volunteer (especially if you are willing to work for free or for college credit). However, the reality is also that researchers may not be in a place at the moment to have something productive for you to do. Furthermore, many researchers (particularly professors at large universities) are bombarded by e-mails from students interested in gaining research experience, and your interest can get lost in the chorus of applications. This is why your timing and your pitch are key.

This could be you too! Photo by Charity Juang.

As for timing, research tends to happen in fits and spurts that depend on the availability of research funding. Research can be slow when there’s no money to buy supplies and equipment, pay travel expenses, pay for animal care, and pay salaries. But when a grant does come through, the researcher is suddenly under intense pressure to collect and publish data as quickly as possible before the grant runs out. It’s hard to tell when a particular researcher may have funding, so one good strategy is to keep your eyes and ears open. Sometimes researchers post announcements around their departmental buildings when they're recruiting undergraduate research assistants. Positions and internships may be announced online. But more commonly, positions are filled before they're even announced. So how do you get a coveted position that isn’t even announced?

The best strategy is to contact researchers you are interested in working with as soon as you discover them and conveying your background and interests. They may not have an opening at the moment, but if you remind them of your availability and interest periodically (at the start of each semester, for example), you will likely be among the first to be informed when a position does open up.

What should you say when you contact a researcher you would like to work with? Generally, researchers want to know a few things when being approached by a prospective research assistant:

1. If you are a student, what year are you? Training an assistant is usually a sizable time commitment. During an assistant’s first year, researchers spend as much or more time training the assistant than the assistant contributes to the project. For that reason, researchers usually prefer to hire someone who is likely to stay in the lab beyond a year. The more time you have before you graduate, the more desirable you are as an applicant.



2. What are your research interests and how do they relate to the lab you are applying to? Researchers want assistants that are self-motivated. If you are genuinely interested in the project you will be working on, you are more likely to do a good job and get more out of the experience.



3. What do you hope to gain out of such a research experience? Do you want experience with a particular technique or species? Are you hoping to work for pay or are you willing to work for college credit or just for the experience of it? Be honest here (especially if you need this to pay rent), but keep in mind that most labs don’t have money to pay assistants.



4. What do you have to offer? If you are interested in field research, mention if you are an experienced outdoors enthusiast. If you are interested in learning wetlab techniques, mention your attention to detail. If you are willing to do menial tasks such as dishwashing and maintaining equipment, that could be a major selling point.

Your initial e-mail should be brief (a short paragraph is most effective). But you may want to attach a résumé as well. At the very least, your résumé should list any previous research experiences, classes you have you taken (biology, statistics, chemistry) that may be relevant to a project in this lab, and leadership/work positions you have held.

If you start early in your search and are persistent (but not pushy), you should be able to find a research position within a year. Good luck!

For more advice on applying to graduate programs, go here.

Not Quite Like a Rolling Stone

Dung beetles are competitive little critters. And who can blame them? When a fresh pile of poo is at stake, wouldn’t we all be a bit competitive? …Okay, maybe not. But animal dung is actually chock-full of nutrients, which makes it a precious resource to the animals that can make use of them. The approximately 6,000 species of dung beetles and their babies are among the animals that make excellent use of those resources.

Mmmm... A poo-pile worth fighting for! Image by Duwwel at Wikimedia.

But even animal dung is a limited resource. When it is plopped out, dung beetles gather from far and wide (okay, maybe not that far) to compete over the miraculous manna from heaven. Many dung beetle species, such as the South African dung beetle, forms round balls of poo to prepare them for transport, and then rolls them away from the poo-pile. This process of forming the poo-ball and getting it away from the poo-pile must be quick. Otherwise, dung beetles that are either less fortunate or less-inclined to work for their poo-balls will try to steal pre-made poo-balls from those that worked to form them.

But this isn’t a story about competition. This is a story about navigation.

The fastest way to get a poo-ball away from the poo-pile is in a straight line, and dung beetles are experts at pushing their poo-balls in straight lines. Researchers have played countless tricks (like adding obstacles and spinning floors) on these guys to try to confuse them into going the wrong way, but to no avail. These guys always seem to know where they want to go. But how?

There are many methods animals use to navigate. Some use celestial cues, like the placement of the sun or the stars, to know what direction they are facing. Some remember the placement of landmarks in places they visit often, such as their home. But many combine strategies to get a more accurate idea of where they are going.

Marie Dacke and Marcus Byrne from the University of the Witwatersrand in South Africa, and Jochen Smolka, Eric Warrant, and Emily Baird from Lund University in Sweden set out to test the relative importance of landmarks and celestial cues in South African dung beetles.

A dung beetle rolls his poo-ball backwards. Photo by Dewet at Wikimedia.

South African dung beetles face backwards when they roll their poo-ball away from the poo-pile. In this position, they should always be able to see the poo-pile and perhaps use the pile itself as a landmark. To test this, the researchers placed beetles on dung piles and waited for them to make a poo-ball and roll it away. Once they got 75 cm away, they moved the dung pile 45° to the left or to the right with respect to the beetle. If the beetles use the dung pile as a landmark, the new location of the pile should make the beetles change course by 45° as well. But they didn’t.

Next, the researchers tested whether dung beetles rely on more distant landmarks to know where they’re going. They created two adjacent, but different, testing arenas: One had an unobstructed view of the surrounding landscape (called the “landmark arena”), and the other was surrounded by a beige featureless wall (called the “no-landmark arena”). Both arenas had a full view of the sky and its celestial cues. They placed beetles and their poo-balls at the center of the landmark arena and allowed them to roll away at least 80 cm. Then they picked them up and placed them in the no-landmark arena and waited to see if the removal of landmarks caused them to roll in the same direction or change bearings. They repeated this in the opposite direction to see if the addition of landmarks could improve accuracy. To check if simply moving the beetles affected their rolling directions, they also picked beetles up and returned them to their original arenas (these were the control beetles). In the end, the beetles that changed arenas did not navigate any differently than the beetles that were picked up and returned to their original arenas, indicating that as long as the beetles can see the sky, they don’t seem to rely on landmarks to navigate.

To test if the sky provides important navigational information to the dung beetles, the researchers put little cardboard hats on some of them to block their view of the sky and had them roll their poo-balls from the center of a wall-free arena with full view of landmarks. Other beetles were allowed to roll their poo-balls without the obstructive hats. But just to be sure the hats themselves weren’t causing the beetles trouble (other than by blocking their view of the sky), the researchers also tested a group with transparent plastic hats. They found that the beetles with no hats or with clear hats rolled their poo-balls just fine. However, the beetles with dark cardboard hats spun in circles, whirled and twirled, apparently having the darnedest time going in a straight line. But a dung beetle doesn’t have to wear a cardboard hat to lose track of the sky. The researchers tested beetles on a clear day with hats, on a clear day without hats, and on an overcast day without hats. The overcast sky screwed up the little buggers almost as much as the cardboard hats did!

Combined, these studies show that the South African dung beetles rely almost entirely on celestial cues and don’t seem to rely on landmarks at all. Even the dung pile, which is always a large, central easy-to-see landmark, seems to be completely ignored by the poo-rolling dung beetles. This heavy reliance on a single type of navigational cue is unusual in the animal world, and you can imagine the havoc it would wreck if all animals got so lost every time there was a cloudy day. But for the South African dung beetle, the consequences aren’t as high as they are for other species. They aren’t taking their poo-balls to a specific location, just away quickly, so they’re never truly lost as long as they’re with their poo. And if the worst happens and someone takes their poo-ball, they can go make another.

We can learn a lot from these guys. In life we face obstacles, we go unknown directions, and we get lost. But no worries… The sun will come out again soon.


Want to know more? Check these out:

Dacke M, Byrne M, Smolka J, Warrant E, & Baird E (2013). Dung beetles ignore landmarks for straight-line orientation. Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology, 199 (1), 17-23 PMID: 23076443

Risky Business: Ape Style

The decisions of this chimpanzee living in the
Tchimpounga Chimpanzee Sanctuary are affected
by his social situation. Photo by Alex Rosati.

If you have a choice between a prize that is awesome half the time and totally lame the other half of the time or a mediocre prize that is a sure-thing, which would you choose? Your choice probably depends on your personality somewhat. It may also depend on your needs and your mood. And it can depend on social contexts, like if you’re competing with someone or if you’re being watched by your boss or someone you have a crush on.

All animals have to make choices. Some choices are obvious: Choose the thing that is known to be of high quality over the thing that is known to be of low quality. But usually, the qualities of some options are uncertain and choosing them can be risky. As with us, the likelihood of some primates, birds, and insects to choose riskier options over safer ones can be affected by outside influences. And we aren’t the only species to have our risk-taking choices influenced by social context.

Anthropologists Alex Rosati and Brian Hare at Duke University tested two ape species, chimpanzees and bonobos, in their willingness to choose the riskier option in different social situations. They tested chimpanzees living in the Tchimpounga Chimpanzee Sanctuary and bonobos in the Lola ya Bonobo Sanctuary, both in the Democratic Republic of Congo. Most of the apes living in these sanctuaries are confiscated from poachers that captured them from the wild for the pet trade and for bushmeat. In these sanctuaries the animals live in social groups, generally spending their days roaming large tracts of tropical forest and their nights in indoor dormitories. This lifestyle rehabilitates their bodies and minds, resulting in psychologically healthy sanctuary inhabitants.

It is in these familiar dormitories that Alex and Brian tested the apes’ propensity for making risky choices. For their experimental set-up, an experimenter sat across a table from an ape and offered them two options: an overturned bowl that always covered a treat that the apes kinda like (peanuts) versus an overturned bowl that covered either an awesome treat (banana or apple) or a lousy treat (cucumber or lettuce). In this paradigm, the peanut-bowl represents the safe choice because whenever the ape chooses it, they know they’re getting peanuts. But the other bowl is the risky choice, because half the time they get fruit (yum!), but the other half of the time they get greens (bummer).


This figure from Rosati and Hare's 2012 Animal Behavour paper shows Alex demonstrating the steps they would go through before the ape chose one of the two options.

After spending some time training the apes to be sure they understood the game, the researchers tested their choices in different social situations. In each test session, the ape was allowed to choose between the two bowls (and eat the reward) multiple times (each choice was called a trial). But before the test session began and in between choice trials, another experimenter sat with the ape for two minutes and did one of three things: In one group, the experimenter sat at the table and silently looked down (they called this the “neutral condition”). In another group, the experimenter repeatedly offered the ape a large piece of food, pulling it away and grunting whenever the ape reached for it (they called this the “competitive condition”). In a third group, the experimenter tickled and played with the ape (they called this the “play condition”).

Alex and Brian found out that whereas bonobos chose the safe option and the risky option about equally, the chimpanzees were significantly more likely to choose the risky option. But despite this species difference, both species chose the risky option more often in the “competitive condition”. Neither species increased their risk-taking in the “play condition”.

The graph on the left shows that wheras bonobos chose the safe option and the risky option each about 50% of the time (where the dashed line is), the chimpanzees chose the risky option much more often. The graph on the right shows that both species chose the risky option more often in the "competition condition" than they did in the "neutral condition". Figure from Rosati and Hare's 2012 Animal Behavour paper.

These are interesting findings, especially when you consider the natural behaviors and lifestyles of these closely related species. Bonobos can be thought of as the hippies of the ape world, happily sharing and using sex to settle disputes and strengthen relationships. In comparison, chimpanzees are more like gangsters, aggressively fighting over resources and dominance ranks. So in general, the more competitive species is more likely to take risks. But when the social environment becomes more competitive, both species up the ante. This effect doesn’t seem to be simply the result of being in a social situation, because the apes didn’t increase their risk-taking in the presence of a playful experimenter.

This still leaves us with some questions to ponder though. Are apes more likely to take risks when an experimenter is offering food and taking it away because of a heightened sense of competition, or is this the result of frustration? And would we see the same effect if the “competitor” were another ape of the same species, rather than a human experimenter? How would their behavior change if they were hungry? These questions are harder to get at, but this research does demonstrate that like in humans, the decision-making process in chimpanzees and bonobos is dependent on social context.


Want to know more? Check this out:

Rosati, A., & Hare, B. (2012). Decision making across social contexts: competition increases preferences for risk in chimpanzees and bonobos Animal Behaviour, 84 (4), 869-879 DOI: 10.1016/j.anbehav.2012.07.010

Those Aren’t Chocolate, Easter Bunny!

The Easter Bunny has a dirty secret. When he’s not hopping around in his pristinely white fur hiding beautifully colored eggs and decorated baskets full of treats…he’s eating his own poo. Gross!

Never trust a rabbit. Photo by the Mosman Library at Wikimedia.

But don’t judge him before you understand him. It’s not that he chooses to eat poop, but that he has to for his own health. In fact, all rabbits do.

Rabbits are herbivores, which means that they only eat plant material. Plant material is very difficult to digest, although it may not seem like it (I mean, we eat plants all the time with no problem, right?). But when it comes to digestion, it’s not what you put in your mouth and swallow that matters, but what your body can break down.

This process of breaking down food depends on digestive enzymes, a group of chemicals that break down food. Each type of digestive enzyme is specific for breaking down a particular type of food chemical. Plant material is so hard to digest because it is largely composed of cellulose, a sugar that we vertebrates don’t have an enzyme for.

Herbivorous animals that lack this enzyme have developed an alternative strategy to get the nutrients they need out of these plants – They have microbes that live in their guts and ferment the plant material. Many of these microbes, which include bacteria, protists, yeast and fungi, produce the enzyme needed to break down cellulose. But these microbes are slow-acting (which means herbivores with longer guts get more nutrients), and they are sensitive (which means herbivores with special microbe gut chambers get more nutrients).

Rabbits have a special gut chamber called a cecum (or caecum) that houses many of their gut microbes. The cecum is so important to rabbit digestion, it’s even bigger than their stomach! When a rabbit eats something, the food is broken down by chewing, swallowed, and passed on to the stomach (follow along with the diagram below). The stomach stores and sterilizes the food while breaking down some of the nutrients before it passes the food on to the small intestine. The small intestine absorbs the nutrients it can before the remaining food gets sorted at a fork in this digestive road. The fibrous food parts move on to the colon, where it is converted into little hard turd-balls. The non-fibrous parts go to the cecum, where the microbes living there work their magic, breaking down the remaining food into absorbable nutrients.

This diagram of the rabbit digestive system was posted by Sunshineconnelly at Wikimedia. Trace through it as we talk about where each digestive step happens.

The trouble is, this food has already passed the part of the digestive tract that absorbs most of these nutrients: the small intestine. Now, it has nowhere to go but out. So the cecum pushes these remaining nutrients into the colon, which turns them into cecotropes (or caecotrophes): mucus-covered, nutrient-rich, moist turds shaped like a bunch of grapes (and according to the Easter Bunny, just as delicious). And the only way rabbits can get the nutrients (and remaining microbes) out of these little nuggets is to send them through the digestive tract all over again by eating them. So that is what they do.

Eating poo sounds gross and unusual, but it is actually fairly common in the animal kingdom. So common, in fact, that there is a term for it: coprophagia. Hamsters and capybaras have similar digestive tracts to rabbits and eat their own poo for the same reasons. Other animals, like elephants, hippos, pandas, and koalas, are born without the necessary microbes to digest the food available, so the babies obtain these microbes by eating their mothers’ poo. And many coprophagous insects, like flies and dung-beetles, subsist on diets composed of the poo of large animals.

So don’t hate on the Easter Bunny for his repulsive ways. He can’t help what he is. Just appreciate him for all the chocolate eggs he brings you every Easter. Wait… Those are chocolate eggs he brought you, right?

How To Get Into An Animal Behavior Graduate Program: Getting Good Recommendation Letters

It’s hard to feel strong and confident when
asking for recommendation letters leaves
you feeling like this. Photo by Jan Mehlich
at Wikimedia.

You’re applying to graduate schools and you’ve been fretting about your grades, your test scores, and your essays for months. And then you remember about the recommendation letters – How many did they want? Three?! Ugh… Why do they make people jump through these hoops, anyway?

 

Turns out, the recommendation letters are a critical component of the graduate school application and they can make the difference between acceptance and rejection. You don’t just want 3 rec letters - You want 3 awesome rec letters. And although it may feel like the quality of letters written by other people is out of your hands, there are several things you can do to maximize the quality of the letters people write for you.

 

Before you start asking people to write rec letters, it’s important to think about how these letters are used. Generally, an admissions committee will go through applications to filter out those applicants that don’t meet the minimum standards with respect to grades, test scores, and prerequisites. Those applications that make it through the first pass are then sent on to the researchers the applicants have requested to work with. If the researcher you would like to work with is looking for graduate students that year, he or she will assess your full application. The rec letters are used to get a feel for your initiative, dedication, maturity, intelligence, creativity, ability to work with others, leadership skills, and communication skills. The better a letter can highlight these attributes about you in a personalized and detailed way, the more effective the letter will be in convincing the researcher to welcome you as a new lab member.

 

The most important step of getting good rec letters is asking the right people. When someone writes a rec letter for you, they can only talk about what they know about you. You may have had the most incredible and respected professor in the world, but if your only interaction with her was as a student in her 200-student lecture, she’s probably not going to have much to say about you other than what your grades were in her class. Even if you got an ‘A’ in that class, she probably won’t be able to write about the personal attributes a researcher would want to know about you. You want to request rec letters from people who know and think highly of you and your abilities (which means you must have been awesome in their presence). Secondarily, you want to ask people who hold respected positions. Some examples of good people to ask are research supervisors (if they know you well enough, a professor’s letter would typically be considered more highly than a graduate student’s letter), work supervisors (the more your work related to animal behavior or biology, the better), and professors that personally interacted with you (especially if they could write about your involvement in class projects).

 

Once you’ve chosen the people you would like to ask, there is a lot you can do to increase the likelihood that that their letters will be great (and submitted on time). Chances are, the people you are asking for rec letters already have a lot on their plate. The easier you make it for them, the less they will forget. Prepare a packet for each person who will write a rec letter for you. This packet should include:

 

• An organized list of all the schools/programs you are applying to, their deadlines, and directions for submitting letters. Include a stamped and addressed envelope for each school that wants your references to mail their letters.
• Your current résumé. This should include your major(s) and minor(s), current GPA, a list of science courses you’ve taken, extracurricular activities, jobs, internships, volunteer positions, honors and scholarships, and research projects.
• A list of your accomplishments with the person writing the letter. This may include what you have contributed to projects and your memories of what you gained from your experience with that person. Include details like dates and project names. This might jog the letter-writer’s memory so he or she can write a more personalized letter.
• Any forms the schools require. Check to see if they require your signature before you include them in the packet.
• All this should be in a folder with your name and e-mail address on it.

Now comes the slightly awkward part: actually asking for a recommendation letter. If you chose your preferred letter-writers correctly, they should know you personally and have an idea of your career interests already, which will make this process less awkward. You can ask if someone would be willing to write you a letter either in person or by e-mail, ideally at least a month before they are due. In this first broach of the topic, you want to communicate your ultimate career goals, what types of programs you are applying for, and how many programs there are. Then you ask if they are willing and able to write recommendation letters for you. Mention that you have more information on the programs and your experiences to provide them if they would like and offer to meet with them to talk more about your goals and experiences.

 

Sometimes, the person you ask will decline because they feel they do not know enough positive things about you to write a strong letter for you (which would indicate that you chose the wrong person to ask or you failed to be awesome in the right people's presence) or because they simply do not have enough time. Just in case, you should have a few extra potential letter-writers in mind. But in most cases, if you chose the right people, they will be happy to write the letters for you. Bring them your prepared packet and chat with them about yourself and your goals. One or two weeks before each deadline, e-mail each reviewer a reminder of the deadline (unless they told you the letters have already been submitted).

 

If your letter-writers know and are impressed by you and your abilities, they should have plenty of good things to write about. If you are organized, you can make sure they remember all those wonderful things about you in time to put them in your rec letter and submit them before the deadlines. The way you approach this request can make the difference between ho-hum letters and door-opening letters.

 

For more advice on applying to graduate programs, go here.

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

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

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.