Eavesdropping ears: mule deer listen to marmot cues

When it comes to Kingdom Animalia, we’re not the only ones that can tap into the conversation!

Our study conducted this summer at the Rocky Mountain Biological Laboratory (RMBL) suggests Mule deer (Odocoileus hemionus) tune into marmot (Marmota flaviventris) alarm calls for hints of nearby predators.

Photo credit: Jenn Smith

Previous scientists noted that mule deer reacted to marmot alarm calls, and we saw this as an opportunity to study interspecific communication in animals of different size, vulnerability and defense mechanisms.

Interspecific communication, or eavesdropping, is when an individual of one species receives and responds to a signal from another species. What’s that information good for, anyhow? Well, if you’re a vulnerable animal foraging, intercepting a pertinent warning can help save your life! Eavesdropping is a useful tactic to learn and can change foraging and antipredator behavior, protection seeking, and group characteristics.

Deer and marmots live in similar areas, and coyotes and potentially mountain lions prey upon both. Therefore, we hypothesized deer would respond to marmot alarm calls versus a common bird song. To test this hypothesis, we conducted a playback experiment.

We recorded mule deer behavior in response to either the song of the mountain white-crowned sparrows (Zonotrichia leucophrys; control), or a marmot alarm call. This was your typical field biology research: wake up before dawn, strap a speaker to your backpack, and head out to track deer, microcassette in hand. Of course, finding deer was usually easier said than done. I quietly recorded the deer behavior 30 seconds prior to and after the sound was played using a prewritten ethogram with typical deer behavior. That information was then analyzed in JWatcher for patterns.

Hiding in veratrum on the search for unsuspecting deer

Turns out for the marmots at RMBL, the marmoteers aren’t the only ones listening in. We found that deer near human settlements had a significantly different response to marmot calls than sparrow songs. Any individuals who heard the call typically became alert and stayed vigilant longer; whereas, those who heard the control were more likely to look and then continue foraging. Deer far from people showed similar responses to marmot calls and sparrow songs probably because they aren’t habituated to a person being around.

Our results are interesting and unique because we have evidence for eavesdropping in animals that are very different in size and vulnerability. These deer have found a potentially reliable source of information through marmots and can use that to either take off into the woods or allocate more time foraging.

There is a lot more work to be done in this field! Future studies can use a remote speaker and camera to study how deer farther away from human settlements react to calls, or how they react to the alarm call of a sympatric species that doesn’t share a predator with them. Perhaps even a study looking at fitness could be useful to know how beneficial eavesdropping is for individuals and populations. The list could go on…

If you’d like to get a more detailed review of this paper, take a look at a copy here.

Meet Team Marmot: Mega and Lawrance

Hello fellow marmot lovers, field biologists, and any other souls out there. We are among the newest additions to Team Marmot.

My name is Mega Patel (pronounced just like it sounds) and I am a second year Biochemistry major at UCLA. I joined Team Marmot because I love all branches of the sciences, and the Blumstein lab seemed like a great place to expand my knowledge on science outside of chemistry. And my name is Lawrance Chung, a third year Biology major at UCLA. I decided to join Team Marmot because I secretly want to be a marmot. Joke aside, I felt that this lab would be a wonderful opportunity to expand my research experience.

Sorting the poop!

Since September 2011, we have been a part of the Blumstein lab. For the first few weeks we did some of the dirtier work, but we know that the resulting data is worth it. We sorted through fecal samples, from the RMBL group, the tagged wild marmots in Colorado, and the captive group, a control group housed at Colorado State University by Greg Florant from which experimental validations of our assays were carried out. Our work is done directly under the mentorship of Dr. Jennifer Smith (shown below).

Jennifer Smith with a captive marmot at
Colorado State University

The purpose of sorting these fecal samples was to get an accurate measurement on how stressed each particular marmot is on a day-to-day basis. While hair samples can provide an idea of how stressed one was months ago, and blood can be used to measure how stressed a particular individual is within a matter of minutes (reflecting trap stress), fecal samples can actually measure how stressed the marmots were yesterday (before the trapping event), which is exactly the kind of data this lab wants to add to its database.

Greg Florant with a captive marmot at

Colorado State University

Like you might have already guessed, we measure the “stress” level of marmots by measuring the concentration of glucocorticoids in their processed fecal samples. The process begins by sort through the fecal sample to obtain a pure sample. This means removing the different fibers, seeds, and occasionally rocks from the sample after creating a nicely mixed bag of feces that we fondly liked to call poo-dough. Then after a single sample was cleaned,it was carefully weighed to 0.20 grams. The accuracy of the weight was very important and we took great care in measuring the samples as close to 0.20grams each as we could. This precision was necessary so that the resulting concentrations of the glucocorticoids could be compared among different marmots. A larger weight could mean a higher concentration, causing the data to reflect the marmot being more stressed than it actually was. In addition, each marmot sample was carefully labeled with an unique ID to ensure that samples from different marmots were not mixed.

Currently we are sorting through and labeling blood and plasma samples from different marmots dating as far back as 2002 and have been preserved in a -80 ˚C freezer. The sorting process involves going through and individually labeling each vial with a unique ID. This sounds much easier than it is because we have to first be able to match up the vial to the correct entry in our database, which does not always happen as sometimes the dates or time will be off. Then comes the tricky part of trying to write on a frozen vial, however, with the help of Emery and Rachel, we have made great progress and will be done within the first week of next quarter.

It has definitely been a wonderful quarter with Team Marmot and we look forward to the next one! Happy Holidays everyone!

Late for work?

Hello world! My name is Lawrance Chung and I have been working at UCLA in Dan Blumstein’s lab for the past quarter. Hopefully most of us don’t find ourselves in this situation too often, but sometimes we are just so tired, that we can’t wake up in the morning. I recently found myself in this position and I was late to lab, but I had a good reason. I saved a life!

As part of the Care Extenders program, I volunteer in the Emergency Room during the night. It just so happened that I was volunteering the night before and an elderly lady needed CPR. Luckily, I happened to be in the right place and at the right time to help her. After around eight minutes, though it felt much longer for me, of CPR we were able to get her heart beating again. It was definitely a successful night.

One thing I didn’t expect was how sore my arms would be afterwards. I was honestly tried. So now, the next time I don’t feel like getting out of bed in the morning, I try to see if I have a better excuse than saving a life, and if I don’t, I get up and head to work.

Honors Project in Progress: Mechanisms Mediating Life History Trade-offs

In lab with a complete glucocorticoid sample

My name is Rachel Stafford-Lewis and I am currently involved with an honors research project in Dan Blumstein’s lab here at UCLA. My research project is a two quarter commitment that focuses on analyzing the trade-offs between reproduction and survival in yellow-bellied marmots. My research specifically focuses on glucocorticoid levels, the amount of white blood cells and parasites in the blood samples, and testosterone levels. I hypothesize that the more dominant and higher-ranking male marmots will have elevated testosterone levels, but that maintaining such rank will prove costly and will also result in high levels of glucocorticoid metabolites, white blood cells, and parasites. I hope to discover the correlation between these three factors, or lack thereof, and analyze my results so as to make sense of the compromise between health and fitness.

The extraction process-halfway through Day One

I will test my hypothesis using data collected in the field at RMBL in the Rocky Mountains of Colorado. I have spent the last seven weeks utilizing this data by collecting glucocorticoid levels from fecal samples in a precise three day extraction process. As seen in the picture above, the tubes contain a yellowish liquid that is a solution of the hormone, alcohol, and water. This mixture evaporates overnight in the vacuum centrifuge, as pictured in the photo below, so that the end result will only be the reconstituted hormone. The entire procedure involves three strict twenty-four hour sessions where I would repeatedly centrifuge and bathe the samples in a hot water bath, put them in a vacuum centrifuge, vortex, and then place them in the -20 degree freezer. The end result was then pipetted into exact sample sizes, as exemplified in the first picture at the top of the page, and shipped off for analysis.

Extractions at the end of day one in the vacuum centrifuge

Now that the extractions have been completed, the next step is to analyze blood smears for various neutrophils, leukocytes, monocytes, eosinophils, and any obvious parasites. This work is done using a microscope and will be measured by counting the number of white blood cells until we have one hundred total in each one of our samples. This portion of my project is especially important because it is the main indicator of health and will be used for comparisons with the glucocorticoid levels as well as the testosterone levels.

Once the blood smears have been examined I will begin the testosterone assays, which will reveal the relative levels of testosterone in each individual marmot. This will be the final component of my project and hopefully will reveal any connection between dominance and survival in regards to parasite and white blood cell count.

A happy marmot out and about in the Colorado sun

I went into this experience knowing very little about marmots and I have come to appreciate them as adorable creatures and as informative research subjects. I hope that this project will further my knowledge of the relationship between survival and health and how it affects marmot behavior in their natural setting. I look forward to completing my research and finding results that will benefit the extensive research that has already been completed in the Blumstein lab.

Good news in the lab...

Several pieces of good news to report have been building up over the past few weeks.

Some key papers have been accepted.

•Carrasco, M.F. and D.T. Blumstein.  2012. Mule deer (Odocoileus hemionus) respond to yellow-bellied marmot (Marmota flaviventris) alarm calls. Ethology.  Malle was an REU fellow last summer and this paper shows that mule deer pay attention to marmot calls.  I think this is really neat because it shows that animals have effects on other species through their vocalizations and the idea of interspecific communication is a topic that needs much more work.

 

•Olson, L.E., Blumstein, D.T., Pollinger, J.P., and R.K. Wayne.  2012.  Beneficial inbreeding:  yellow-bellied marmots do not discriminate against mating with relatives. Molecular Ecology.  This is the final chapter from Lucretia's dissertation that surprisingly shows that male marmots do better NOT trying to avoid inbreeding with close relatives.

•Pollard, K.A., and D.T. Blumstein.  2012.  Evolving communicative complexity:  insights from rodents and beyond.  Philosophical Transactions of the Royal Society.  Kim and I have been continuing our thoughts about how complex communication evolves and this paper stems from a symposium talk that we gave at the animal behavior society meetings this past summer.

•Matt passed his oral qualifying exam.

•We've also (thanks to Jenn's leadership and a lot of work on Rachel's part) just extracted all of our 2011 cort samples and are in the process of sending them off for a radioimmunoassay. 

So, some good news all around.

Scared and Less Noisy

Have you ever heard a marmot's alarm call? I have! It's a distinctive, high-pitched, whistle-like sound that could be clear and piercing, or pretty noisy.

Marmots alarm call when they get scared, be it from predators trying to eat them...

...or from marmoteers trying to bag them (to take their measurements).

The question is - whether the marmot alarm call, this sound of fear, can be a quantitative measurement of just how scared these marmots are. This is what my past year's research is all about. To read the recently published article on this topic by Dan and me, you may have to purchase access to Biology Letters here. For the short, free version, just read on.

Dan and I hypothesized that marmots would produce clearer alarm calls when they are less scared and noisier calls when they are more scared. We used a measure of noise known as Wiener entropy to quantify the noise within the calls. To quantify fear, we measured the glucocorticoid levels found in marmot fecal samples, with higher glucocorticoids indicating greater fear.

We then extracted seven years' worth of data on marmot alarm calls and their associated fecal samples recorded and collected, respectively, in RMBL. These data were compiled by the marmoteers during the summers of 2003 thru 2009; when the marmots called, they recorded them; when the marmots pooped, they picked up after them, and sometimes quite literally, wiped their butts. (Thanks for all the hard work, guys!)

After repeated analyses controlling for all the variables we could think of, including but definitely not limited to sex, mass, age, background noise, and call harmonics, we got the same surprising result - the marmots are generating clearer, less noisy alarm calls when they are more scared.

A couple days' worth of head-scratching later, Dan and I decided that our surprising result makes sense after all. Positive correlations between heightened stress and clearer calls have also been demonstrated in piglets, dwarf goats, and dogs. Of course, formal experiments will have to be conducted to show a causal relationship between fear and the clarity of alarm calls.

In a more intensely fear-induced state, the marmots' vocal folds are pulled more taut, effecting clearer, more piercing calls. The clarity of the call can, in turn, ensure that marmots in the area who hear the call would clearly receive the message. As such, the fear-induced clarity in alarm calls could be selected for within marmot colonies.

Try putting yourself in the situation of a scared marmot. Are your calls likely to be more or less sharp and clear if you experience a heightened state of fear?

Field Ecology in the Digital Age

In early 2010, Dr. Ian Billick, RMBL Executive Director, was awarded an NSF grant for a project entitled "Bringing a Field Station into the Classroom." Working with Dr. Amy Ellwein, newly hired from the University of New Mexico, the intention was to make online tools and some of the long-term data sets collected at RMBL available to college students through interactive curriculum hosted on a new website. Many of you know this as the "CCLI project" for the NSF program that funded it. A Division of Undergraduate Education (DUE) program, CCLI (Course Curriculum and Laboratory Improvement) has since changed to TUES (Transforming Undergraduate Education in Science) and the project is now known to many of us as "Digital RMBL".


One year and a few months into a three-year project, the team is very close to initial completion of most project deliverables, and are moving into the testing and improvement stage. Thanks to many in the RMBL community - you know who you are - we have moved beyond expectations in several aspects of the project's scope. For example, two of our project collaborators liked the structure of the natural history pages so much, they've assigned the project to their students. We now have ten times more natural history pages than we promised NSF, with more in the works. If you would like to lend a hand, Amy has more ideas than time to pursue them, just send her an email: amy AT rmbl DOT org. And keep your eyes peeled for the web debut of Digital RMBL in November at http://rmbl.org/rockymountainbiolab/!

Masculinised female yellow-bellied marmots initiate more social interactions

In a paper just published in Biology Letters, former Blumstein Lab postdoctoral fellow, Raquel Monclús, along with undergraduate Taylor Cook and Dan report on the effects of natural variation in testosterone on female behavior.

We know that the fetal environment may generate profound, lifelong effects. We studied the effects of litter-sex ratio on female yellow-bellied marmots. We found that females growing up in male-biased litters, a situation which exposes them to male hormones during development, were more likely to initiate play and allogrooming as pups, but as yearlings were more likely to engage in estrogen-mediated sociopositive behavior. We suspect that this worked by making these “marmot tom-boys” engage in more exploration, a behavior that led to more encounters with others as well as increasing the likelihood of dispersal. Our results further illustrate the diverse consequences that endocrine disruptors might have in wild animals.

The BBC (along with some other news sources) picked up the story.
Read the BBC article here.

Photo from BBC News Story

Marmot outreach makes news

"Marmot Week" highlighted on RMBL webpage:
(click here to see the original story)

Teaching (and Learning) More About Marmots: RMBL's marmot project is currently in its 50th year. Because of our long track record and and because marmots are such fascinating animals, Team Marmot has many lessons to pass onto the next generation of scientists. Each year, team marmot shares its passion for understanding ecology with young and aspiring naturalists at RMBL's Kids Nature Camp.

Photo by Annie Starr: Jenn Smith quizzing students about the ecology of marmots

This season two marmoteers from the University of California Los Angeles helped students to gain key insights into the secret world of marmots. Jenn Smith (in photo above, quizzes students about marmot ecology) is an American Association of University Women Postdoctoral Fellow and Nicole Munoz is a National Science Foundation Predoctoral Fellow.

They first demonstrated the techniques used to observe and live-trap marmots. Then, Jenn and Nicole explained how they perform manipulative experiments to understand how marmots cope with their social worlds and natural threats. For example, students learned how researchers assess whether or not marmots are capable of distinguishing among the different cues of predators.

Photo by Annie Starr: Students distinguishing between the scents of coyote and deer urine

One highlight from this training exercise occurred when students were asked to distinguish among the predators producing various vocalizations and scents (see above). Students were amazingly astute at distinguishing between coyote and deer urine. After marmot week at RMBL, these inquisitive students are now armed with new knowledge of and enthusiasm for understanding the natural world.

Little man: back by popular demand

Thanks for all of your fun inquires about little man!

Photo by Jenn Smith

For those of you wondering how he is doing in face of predation and with all of his female admirers, the outlook is indeed very good. Little man (below on right) continues to fatten-up for the winter and attract the attention of the females marmots (e.g., "F" on left below).

Photo by Jenn Smith

In fact, as some of you wondered, there are evolutionary trade-offs for fat marmots. Marmots must be fat to withstand months of hibernation, but very fat marmots with slow escape speeds are vulnerable to predation. To understand such trade-offs we continue to live trap and observe all of our marmots.

In fact, after we live trap a marmot from our population, we scurry behind him or her to record the maximum speed at which a marmot is able to run away from a potential threat.

Photo by Jenn Smith

We look a bit silly in the field chasing marmots and even the ground squirrels notice take notice of our odd behavior. As obligate hibernators, ground squirrels also seem to be getting quite chubby these days. This is great for them though because winter will be upon us soon enough!

"Little" man?

Our field season is nearing to an end which means that marmots are putting on body fat in preparation for hibernation.

Photo by Jenn Smith

Above and below are recent photos of the marmot with the mark, "little man." Judging by the size of his stomach relative to his front legs, we need have to consider renaming this marmot "pudgy little guy".

Photo by Jenn Smith

The ladies sure seem to like him though; he currently defends the largest harem of females out of all of our colony sites!

Marmot Blog: Tales of a Marmot Hunter

Check out the following story at, "Tales of a Marmot Hunter," another blog written by a marmot enthusiast also living in Colorado. Although some folks do still hunt marmots, the of this blog, James Parfrey, is simply out hunting for the rush of observing the adventures of marmots, so check it out!

For example, a recent post said, "As we were about to leave, I spotted a rather good looking marmot making his way around the lake, no doubt returning home from a visit with his lady friend. He came all the way around the lake to the outlet, where Icy Brook was racing along.

He was going to cross the creek!!

Sizing things up, he hopped from rock to rock with amazing dexterity!!

Marmots may look like lazy fatties, but they can really move when they have to.

As he made his way across, it became clear that he was heading straight towards us.

He darted behind a rock, and then all of a sudden, we were standing face to face.

We exchanged knowing glances, and then as quickly as he appeared, he was gone."