Fieldwork: Lamanai, Belize

This week I’ve been working with a team of bat researchers in Lamanai, Belize (an archaeological site of the ruins of a Mayan city).  We are collecting data for a study on the effects of sickness behavior on social associations in wild vampire bats. Last year, PhD student Sebastian “Basti” Stockmaier and I conducted two projects on how social behavior is affected by lipopolysaccharide (LPS)—a bacterial endotoxin that challenges the immune system and induces sickness behavior. LPS can cause symptoms of sickness such as fever and lethargy, but the effects are temporary and the animal makes a full recovery because there is no actual pathogen. The effect of LPS on social networks was first studied by Patricia Lopes. She injected mice with LPS or saline and tracked their nest-sharing associations. Mice that were injected with LPS were less socially connected to others. This work is important because it shows that sickness behavior can reshape social networks and therefore change how a pathogen might spread.

Basti and I conducted three studies on the effects of LPS on vampire bat social behavior. In one study, we injected vampire bats with either saline (control) or LPS then isolated them and counted how many contact calls they produced. In another study, we individually fasted bats in a large captive colony housed in a flight cage, injected them with LPS or saline, and then looked at whether they received more or less food from their group-mates. We also looked at whether the sick-feeling bats gave or received more social grooming. Finally, to experimentally remove the effect of association, we tested the effects of LPS effects on grooming given and received when bats were forced into constant association by keeping them with one or 3 others in close proximity. We did this test because sickness behavior might have an effect on both social associations (being in the same place at the same time) and social interactions (e.g. mating, fighting, grooming, food sharing) and although people often use associations as a proxy for interactions, they are not the same thing. These studies were all done while I was in Rachel Page’s Lab at the Smithsonian Tropical Research Institute in Panama, and they should be published this year and next.

Next, I thought it would be good to complement these captive studies by looking at effects of LPS on vampire bats in the wild. So Simon Ripperger, my wife Michelle Nowak, and I joined a field trip that Brock Fenton and Nancy Simmons take to Lamanai every year.  Simon Ripperger is the only person who could track social associations between more than 30 vampire bats simultaneously. We also teamed up with disease ecologist Daniel Becker who has been banding and monitoring the physiology of the vampire bats at Lamanai the last few years.

Brock knew about a large hollow tree full of insect-eating Saccopteryx bilineata, insect and nectar-feeding Glossophaga soricina, and our target: the blood-feeding Desmodus rotundus. To catch the emerging bats, we strung up mist-nets using a jerry-rigged pulley system. Saccopteryx emerged at dusk, followed by the Glossophaga. Next, we began to capture males going in and out of the tree (see images below taken on previous years at the same roost exit by Brock Fenton).


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Vampire bat exiting the roost (above and below). Photos by Brock Fenton.

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After a slow period, we began to catch females exiting around 2 am. By the end of the night we had captured more than 40 females and even more males, and we stopped because we ran out of bags and had more than we needed (image below).


cloth bags each holding a vampire bat

We released 34 female vampire bats with proximity loggers, half being injected with LPS and the other half with saline. Daniel Becker banded both males and females and took blood and hair samples for his long-term studies.

Using Simon’s proximity logger system, we could remotely download encounters between bats over the next 4 nights, without having to disturb or recapture them. The loggers document the duration and distance estimates of encounters among up to 60 individuals at distances from touching to 10 meters. My prediction is that the immune-challenged bats will have fewer encounters with others because they will be less active, and that the effects on association will not be as dramatic as what can be seen when observing the actual interactions.

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Vampire bat with 1.5 g proximity sensor (above and below). Photos by Brock Fenton.

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Some pics from Panama and Germany

I’m finally seeing bats flying around here at dusk in Germany, and for the first time I’m missing Panama a bit. But it’s not that I don’t like Panama, I just love where I am now! I’ve been trying to make the most of my time here, and that’s my excuse for not writing a blogpost in awhile. More research results to report soon. In the meantime, here are some pretty pictures.

The last two years, I was in Rachel Page’s Lab at the Smithsonian Tropical Research Institute in Gamboa, a small town on the middle of the Panama Canal, at the center of the skinniest bit of the isthmus connecting North and South America. In the Canal Zone in Panama, you can drive from the Atlantic to the Pacific Ocean in one hour.


There were free-tailed bats living in the broken air-conditioning unit in our bedroom, and tent-making bats above our back door. On some days, the Gamboa titi monkeys (Geoffrey’s Tamarins) would stop by and we could feed them bananas. Samuel Diaz Munoz did his PhD on this population studying their fascinating system of cooperative breeding. A female mates with two or more males, and the males cooperate in caring for the young and carry them everywhere on their back.

There was a new species of free-tailed bat discovered in Gamboa. Here’s a picture we took of species of bat in Gamboa

This November I came to the Max Planck Institute for Ornithology to join Damien Farine’s lab in Möggingen, which is a tiny adorable village on the outskirts of Radolfzell, which is a lovely small town near Konstanz, which is beautiful small college town, which is next to the very scenic Lake Konstanz, which is on the German border with Switzerland. That means we can see some of the Alps!

Möggingen is really quaint and bucolic. This is the very modern main institute building. Inside there’s a two-story indoor bird cage.

Most of the Department of Collective Behavior (including the groups of Iain Couzin and Alex Jordan) are in Konstanz. But Martin Wikelski, Dina Dechmann, Kamran Safi, and Lucy Aplin are all people whose work I know about that are based here, just down the road. The research being done here is awe-inspiring:

I work in this building straight out of Grimm’s Fairy Tales, called ‘the mill’.




the backside of the building facing the garden


homes for mason bees in the garden

We are right next to a small pond and a castle. (There ain’t no medieval castles where I’m from).


Living here and working in Damien’s lab has been fantastic. Last week, our lab had a get-together to say goodbye to MSc student James and celebrate him defending his Masters and being accepted to doing a PhD.



James is pretty stoked.


The star of the lab is Lucy and Damien’s cute parrot named “Gili”







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Tracking our vampire bats after they are released into the wild

After almost 2 years of cooperation experiments in captivity, we are now attempting to monitor the social relationships of our vampire bats as we release them back into the wild. We are hoping to track bat-bat and bat-cow encounters. To do this, we are attaching networked proximity sensors to 23 previously captive and captive-born bats with known social relationships and 27 new wild-caught female bats. We are then placing the cattle “prey” in a new location they have never been before. A grid of tracking stations will hopefully allow us to reconstruct their flight paths as they approach the cattle. We are also sampling their microbiomes to look at the microbiome similarity between bats within the colony, and at changes with the move from captivity to the wild.

This collaboration involves an international team of researchers including a very generous landowner, several local cowboys, two postdoc biologists (Simon Ripperger and Gerry Carter), two engineering students developing the software and hardware (Björn Cassens and Niklas Duda), several more engineers back in Germany, two field biologists helping with fieldwork and bat wrangling (Jineth Berrío-Martínez and Darija Josic), two PhD students doing the microbiome sequencing (Karthik Yarlagadda and Aura Raulo), and two principle investigators based in Panama and Germany (Rachel Page and Frieder Mayer).

The captive-born bats have apparently so far survived the transition to life in the wild (it’s their sixth day), but the tropical climate is putting the new technology to a difficult challenge. How well will the captive-born bats be integrated into the group? Will relationships formed in captivity be maintained in the wild? Do food-sharing bats also forage together? Hopefully, we will have some answers soon.


Here’s the post describing when we captured the bats from the roost (below).


This project was funded by the National Geographic Society, the Smithsonian Institute, and the German Research Foundation (DFG).

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Final month in Panama

I have only one month left in Panama! We wrapped up data collection for our captive experiments, and we are now shifting to fieldwork. On June 28, I hired our last research intern for Panama, Darija Josic (MSc in Biology), a bat researcher from Croatia. She is helping both Sebastian Stockmaier and I with looking at effects of sickness behavior on contact calling, and she’s constructing an association network of our vampire bat group based on observations of physical contact while roosting (to compare with grooming and food sharing). She will later be helping Simon Ripperger and I track wild and previously captive vampire bats using proximity loggers.


Through my university education, I have gained a good foundation in biology, with a focus in ecology, and later in physiology and immunology. During my studies I became a member of the Biology Students Association where my main interest were bats, and since then I have been actively involved in bat research. I took part in many field studies, often on surveys in Croatian National and Nature Parks. This is my first time in the tropics and I am discovering many amazing bat species living here.

I am contributing to the ongoing experiments on social behavior of vampire bats in the Rachel Page lab at STRI. The time that I am spending here at STRI working with Dr. Gerald Carter is an amazing opportunity to see first-hand how behavioral experiments are setup and executed and I have been learning a lot about data analysis. I had a chance to hear and meet so many great individuals working on a broad variety of research topics. In my future I hope to pursue further research on bats. The experience I’m gaining in Panama will help me tremendously in my career.

Angela Freeman (postdoc neuroendocrinologist from Cornell) is here this week to help us look at the neuroendocrine basis for social behaviors in bats. Angela has studied the mechanisms underlying communication and social behavior in many species including peacocks, ground squirrels, and pouched rats, and now fruit bats and vampire bats!

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Brunch to say ‘Farewell’ to Claire and ‘Happy Birthday’ to Jineth. Top row: Gregg Cohen, Gerry Carter. Bottom row: Michelle Nowak, Jineth Berrío-Martínez, Angela Freeman, May Dixon, Claire Hemingway, and Darija Josic

Today, Simon Ripperger and engineers Niklas Duda and Björn Cassens are arriving with their incredible high-resolution tracking system.

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More on both these projects (with Angela and Simon) in future posts…


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Meeting with the vampire bat control team, and footage of a white-winged vampire bat

On September 1, bat workers with the Ministry of Agricultural Development (MIDA) in Colon visited the Gamboa Bat Lab. We had an amazing and informative meeting and shared experiences working with vampires and other bats. We are hoping to develop some new long-term projects on vampire bats and discuss useful information to help solve the conflict between vampires and humans through inter-institutional cooperation.

El 01 de septiembre, personal de MIDA-Colon liderado por el Dr. Rogelio Singh visitó nuestro BatLab en Gamboa. Tuvimos una reunión increíble e informativa para compartir experiencias sobre murciélagos y vampiros. Esperamos desarrollar algunos nuevos proyectos a largo plazo sobre vampiros y discutir información útil para ayudar a resolver el conflicto entre vampiros y humanos gracias a esta cooperación interinstitucional.

–Jineth Berrío-Martínez


My research assistant Jineth Berrío-Martínez organized a meeting between the Gamboa Bat Lab and the vampire bat control team at the Ministry of Agricultural Development (MIDA) in Colon. We talked about possible ways that they could help us by sharing information about relative abundance of vampire bats and/or rabies outbreaks, and that we could help them by sharing the latest research of vampire bat rabies, coming from disease researchers like Daniel Streicker and Daniel Becker. One of the most important lessons is to be sure to distinguish between the vampires and the more ecologically beneficial fruit, nectar, and insect-eating bats that spread seeds, pollinate flowers, and control insect pests.


While working with the MIDA crew, we caught a rare white-winged vampire bat (below), a species the team had not yet seen in Panama. We also saw another bat feeding on a chicken in a tree.



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Job opening: Animal Behavior PI position at Smithsonian Tropical Research Institute (also 3 ecology positions)

The Smithsonian Tropical Research Institute (STRI) has openings for 5 Staff Scientists. These are Principle Investigator positions where you run your own research lab as if you were a professor, but with minimal teaching duties. The STRI Staff Scientists pursue independent, internationally recognized research programs in the tropics. Example.

Previous tropical experience is not required. We are especially interested in hiring scientists in animal behavior, terrestrial microbial ecology, forest biology and marine science. The animal behavior position is below.


The Smithsonian Tropical Research Institute (STRI;, headquartered in the Republic of Panama, is seeking an outstanding behavioral biologist to establish an independent world-class research program in animal behavior. The successful candidate will apply a deep understanding of natural history to resolve basic questions about behavioral mechanisms, evolutionary processes, and adaptive function. Areas of specialty may include, but are not limited, to behavioral ecology, evolution of behavior, sensory and neuroethology, chemical ecology of behavior, behavior developmental physiology and functional morphology, and the genetic basis of behavior. Candidates working on any animal taxa, marine or terrestrial, will be considered. Previous experience working in the tropics is not required. The successful candidate will have opportunities to mentor pre- and post-doctoral fellows drawn from an international community, and collaborate with the entire Smithsonian staff.

STRI has state-of-the-art research facilities, as well as terrestrial and marine field stations, and reserves throughout the country. There are environmental monitoring facilities, a large, multilingual support staff, and a library with extensive holdings in the natural sciences, as well as electronic access to all the Smithsonian libraries. The Republic of Panama and the adjacent regions of tropical America are phenomenally rich in terrestrial and marine habitats. The new staff member will join a vibrant scientific community of 30 staff scientists, and an international community of over 1500 scientific visitors per year, including fellows and interns supported through the Smithsonian. Staff scientists maintain diverse research programs covering ecology, evolution, physiology, development, and behavior of marine and terrestrial organisms and ecosystems, both ancient and modern, and the role of human interactions in shaping tropical environments. Staff scientists are not limited to conducting their research in or near Panama.

The position consists of full-time research. Internal funds are provided for laboratory setup, core ongoing research and travel. Staff scientists may supplement their basic yearly research budget by competing for additional intramural and external research funds. Staff scientists are evaluated on their research accomplishments. There is no official tenure, but rather a system of periodic reviews that allows for long-term research projects. For more information on working at STRI see the FAQ:

No formal teaching is required, but in addition to mentoring post-doctoral fellows, students, and interns, STRI scientists are encouraged to teach in graduate training programs with affiliated universities, and to participate in outreach to local and international audiences.


Early- to mid-career candidates are encouraged. Annual salary is commensurate with experience. Compensation packages are internationally competitive, and include allowances to support educational expenses for dependent children at international schools. The position is based in the Republic of Panama. Relocation expenses are provided.

Qualifications: A Ph.D. and post-doctoral research experience in a relevant field, an outstanding publication record, demonstrated success in obtaining research grants, a history of successful collaborative research, and demonstrated skill in communicating science to the public.

To Apply: Please submit the following as PDF files: a cover letter, curriculum vitae, statement of research accomplishments and interests in animal behavior and related fields, PDFs of three to five significant publications, and the names and contact information of three references to Address inquiries to Dr. Rachel Page, Chair, Animal Behavior Search Committee, at

Positions are open until filled; review of applications will begin on November 15, 2017 and interviews will commence shortly thereafter.

STRI is an equal opportunity employer and is committed to diversity in its workforce. Appointments are made without regard to nationality. In addition this position in animal behavior, STRI is currently filling staff scientist positions in terrestrial microbial ecology, forest biology and marine biology, and is supportive of the needs of dual career couples. For more information on the positions STRI is offering, please see our webpage:

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Behaviour17 Conference

Scientific conferences are some of the biggest highlights of my year. I just attended the Behavior2017 Conference in the beautiful seaside town of Estoril, Portugal.

Pictures Colour Library  - PCL

Estoril: warm sun, cool breeze and seawater

I’m still early enough in my scientific career that when I attend a conference, I often meet, for the first time, people whose work I’ve read. Public speaking is always a bit scary, but it’s such a joy to come together with people from all around the world who are working on similar, related questions in different organisms. There is not enough time to go over all the talks, but here’s a small sample.

Jonathan Pruitt gave an engaging talk on something he calls “social susceptibility” which is the extent to which the collective behavior of a social group is affected by a “leader” or keystone individual. In his remarkable social spider system, there are different discrete behavioral types (personalities), and introduction of a single extremely bold aggressive individual can make the entire colony more aggressive (more individuals attack). But this effect only occurs in deserts, not in the less dry savannah, because the aggressiveness of a colony is only advantageous in deserts. Pruitt tested whether the social influence of the bold individual (the leader) is determined by the traits of the leader or the followers. And apparently, it’s the followers that matter, not the bold leader. In deserts, the shy followers are influenced by a bold individual from either a desert or a savannah or even a heterospecific spider. In savannahs where aggressiveness is not adaptive, the shy individuals were not influenced by this extreme individual. Pruitt ended by making a general (obviously political) metaphor that influential “leaders” can only have be influential if the surrounding society as whole follows them, and varying levels of this “social susceptibility” can exist from group to group due to different selection pressures. As Pruitt put it, given high enough social susceptibility, a society can even be greatly influenced by a “heterospecific sham” (I found that bit hilarious). It’s a fun and complex story, and Pruitt told it well.

Another favorite talk was by my friend Neeltje Boogert on the effects of early life stress on social learning in zebra finches. Using a series of clever experiments, she and others found that when solving foraging “puzzles” young birds copy their parents, but when the young were given stress hormones, they stopped copying their parents and instead copied unrelated adults! Neeltje then did a similar study with song learning and found that young males tended to copy the song of their father, but the experimentally stressed juveniles did a worse job copying their father’s song. The stressed males had weaker father-son bonds and they may also have been more likely to copy non-father males. I wonder if similar phenomenon exist in humans: do highly stressed kids start learning earlier from their peers rather than their parents?

Another great talk was by Amiyaal Ilany, also about parent-offspring relationships in the context of social networks. Ilany had previously worked on a model exploring the idea of maternal inheritance of social networks (something I hope to test in vampire bats when I get a large enough sample size). Here, Ilany applied this idea to a huge long-term dataset collected by the Holekamp Lab from wild hyaenas. He showed that a hyena does indeed have similar network ties to her mother. This similarity depends on maternal social rank, in that offspring of mothers of higher rank inherit a stronger similarity to their offspring’s network position. The social inheritance of bonds also depends on the amount of time that the individual spends with their mother. One of the great thing about this study is that it shows where social network structure comes from.

I finally met Thomas Bugnyar (even if only for a moment). He gave a terrific talk on social cognition in corvids. He showed that ravens adjust their calling behaviour according to who was in the audience. The victims of an attack from another raven called more when their kin and bonding partners were present but called less when friends of the aggressors were in the audience. I’m a big fan of his work on social cognition and sociality in ravens and the corvids themselves.

Rene van Dijk gave a great talk on vocal kin signatures and kin discrimination in social weaverbirds. I’m hoping to look at paternal vs maternal kinship signatures in calls soon in vampire bats; I’ve been collecting data on this since 2009.

Sue Healy gave a great talk on the how birds build nests. There’s surprisingly many decisions involved about materials, colors, shapes and structures, and again, how early life experience can affect nest-building. I always love reading or hearing about cognition experiments, because the experimental designs are always so clever.

Barbara Taborsky discussed evidence from their cooperatively breeding cichlids about how a subordinate uses either helping or a submissive display to prevent aggression and eviction by dominants. The submissive display might somehow honestly signal that there is no challenge to the dominant. Interestingly, although the strategy can vary based on the immediate social context, there is consistent individual variation in strategy use. But it is not heritable. Instead, it comes about through something like a lifetime specialization into either ‘helper’ or a ‘submissive’ type based on early life experience. This later influences whether the subordinates either disperses, or stays and helps at the nest.

There were many other studies that manipulated the early environment and looked at effects on social behavior. For example, in zebrafish early environments influence social competence and gene expression in the brain years later.

Michael Taborsky gave some interesting new results on different cooperative strategies employed by cooperatively breeding cichlids, including reciprocity. I’m excited to see those papers when they come out. I’m hoping to do some experiments with reciprocity in rats next year.

There were several terrific posters from University of Exeter on cooperativeness in predator-inspecting guppies. They seem to have a really fantastic department there for animal behavior.

I enjoyed Dustin Rubenstein‘s “big picture” talk about comparing animal societies (including the often ignored taxa like spiders, thrips, and shrimps) to understand social evolution with some neat results from his work on snapping shrimp. It was great to finally see what these snapping shrimp look like! I’m really impressed with the number of systems that his lab works on in the field.

I had an interesting discussion with Dieter Lukas and Corina Logan about brain size evolution (see their recent review manuscript) and the necessity for open access (and other changes to publishing in science).

Yvonne Zurcher had an interesting poster showing evidence that vocal similarity influences the development of pair bonds in common marmosets (in addition to call convergence once bonds form).

Frans de Waal gave an entertaining talk with fun videos of nonhuman primates cooperating.

I have better appreciation for the idea of indirect genetic effects after this meeting.

Hanna Kokko, a leading theoretical biologist in evolution and ecology, gave a talk that changed the way I thought about evolutionary bet-hedging (which I mentioned at the start of my talk on “social bet-hedging”). I was a bit worried she would not like my rather loose use of the term “bet-hedging” but instead she seemed quite interested in my idea of how individuals invest in social relationships, which was very exciting for me. When we spoke I was a bit too nervous and star-struck actually. I think I stammered something like “I really love your book on modeling. But I’m really sorry…. I did not finish it…. I only made it to Chapter 3 when I was in grad school…” [And then maybe I trailed off because my brain was screaming: WHY ARE YOU SAYING THIS?]. Alas, this is one of those embarrassing moments that I’ll think about later randomly and shudder.

Barbara Koenig described her recent work on sickness behavior and its effects on social networks. This is of great interest to me, because we are now doing similar experiments in the vampire bats, led by Sebastian Stockmaier. The first paper should be out next year.

I took notes on far more talks and posters, but this blogpost could go on forever, so I’ll stop here.

There were several more prolific people I wanted to meet such Redouan Bshary and Frans de Waal. But so often I think to introduce myself, they are talking with someone else, and I started to think to myself, Do you actually have anything to say other than ‘I love your work!’ ?”. Then I would think, “What’s a good question I have for him?” … and then I start overthinking and then the moment is gone, hahaha. If I read enough papers that I like by someone, they eventually (and quite irrationally) begin to seem like some sort of celebrity to me. This is strange because I don’t generally like the idea of celebrities, focusing on people rather than ideas, but… it still happens. For better or worse, academia is just inherently social, with so many of phenomena that are being discussed at this very conference:

  • dominance hierarchies
  • networks of association with individuals greatly varying in centrality
  • leaders and followers
  • early career experiences that set individuals on different paths and specializations
  • reciprocity and other strategies for making cooperative investments while avoiding exploitation,
  • and (of course) “social bet-hedging“– the strategic tradeoff between investing in strengthening of existing relationships and creating new ones


Conferences give me a boost of inspiration. One of the main reasons I love conferences is that I get a lot of ideas while I’m sitting there listening to talks, or from the talk itself, or from conversations with people. In my crazy busy life at Panama, I almost never have time to just sit and think about ideas; I’m always caught up in the details of a particular experiment.

The next meetings I hope to attend are something called “CBEN 2017” and this one, both on social complexity and cooperation.



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