Summer of fieldwork: Costa Rica

In July, Jeff Riffell, David Villalobos and I went to La Selva Biological Station in Costa Rica to work on our NSF-funded project “Chance or necessity? Adaptive vs. non adaptive evolution in plant-frugivore interactions”. Going in the middle of the rainy season during an El Niño year made for a very stormy, wet, muddy and soggy couple of weeks. In what I’d like to call “the field season triathlon” (hiking, trawling, and reaching up), we were able to collect Volatile Organic Compounds (VOC) from the fruits of over a dozen species of Piper and other bat-dispersed plants, and fecal and tissue samples from nearly 100 bats. While mapping the VOC profiles onto phylogenies will enable us to investigate how fruit scent evolves in this system, analyses of the bat fecal samples will allow us to expand our current understanding of how much the bats rely on the different Piper species for food.

This autumn, Leith Miller and Ada Kaliszewska are continuing sample collection and analysis for this project in La Selva. Meanwhile, Laurel Yohe (a PhD student at our collaborating lab) gave a talk at the North American Symposium for Bat Research in which she presented preliminary results  on the olfactory receptors of short-tailed fruit bats.



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Summer of fieldwork: The Philippines

Time flies when you’re having fun, or if you are catching bats around the world, which is basically the same thing. This is the first post reporting our fieldwork trips this summer, which included four countries across four ecogeographic regions!

It all started with a trip to the Philippines with a team composed by the Sears, Dávalos, Dumont and Santana labs, Dr. Susan Tsang, and colleagues from the National Museum of the Philippines. Our main goal was to collect Old World fruit bats (Pteropodidae) for a study that will contribute to understanding why these bats have much lower cranial diversity than their New World counterparts (Phyllostomidae). Answering this question involves integrating studies on cranial development, bite force and feeding behavior across a range of pteropodid and phyllostomid species.

What impressed me the most upon arriving to the Philippines was the overwhelming population density (Luzon is the 4th most populated island in the world). Our field sites were near, Liliw, a highland town in the southern portion of the Laguna province. Even several hours away from the capital, there were no apparent sights of the kind of habitats that I would expect could sustain bats. Yet, despite the loss of habitat and the pollution, some bat species still seem to fly through this landscape and take advantage of fruiting trees during their nightly foraging activities. Using mist nets suspended a few dozen meters above the ground, and skipping on any form of night sleep, we were able to collect five of these bat species: Cynopterus brachyotis, Eonycteris spelaea, Macroglossus minimus, Ptenochirus jagori, and Rousettus amplexicaudatus. Though this was a considerably lower diversity than what I’m used to experiencing in the Neotropics, it was astonishing to see these species live for the first time.

From the beginning, it was quite evident that pteropodids are a different ballgame than phyllostomids when it comes to recording performance and feeding behavior. Although both Cynopterus and Ptenochirus were reminiscent of Neotropical Artibeus species in their extravagant use of distress calls in the mist net, their approach towards scary things (like a bite force meter) seemed quite different. These species, as well as the rest of the pteropodids we caught, tended to rely more on their flight response when faced with experimental situations – cue adorable bat covering its face with its wings. With much patience and creativity, however, we were able to get bite force data for new species to complement previous datasets for our study. Likewise, Karen Sears and Dan Urban set up a lab in the field that allowed them to conduct unprecedented experiments and observations on the skull development of several pteropodid species.

My favorite catch of this trip was Rousettus, despite the fact that their activity peaked between 2-4 AM, sending the sleep-deprived team into panic mode to quickly release dozens of bats from the nets before sunrise. Rousettus were extremely gentle bats, and it was a treat to hear their tongue clicks (a form of echolocation) as they flew about and while we handled them. The young of at least one species of Rousettus may learn vocalizations in similar ways to the way human babies do. What’s not to love?

The data and samples collected during this trip will serve for dozens of studies that will expand the understanding of this diverse and still obscure group of bats. As it often happens, I came back with many more research questions than when I left. Here’s to hoping there will be more pteropodids in our future.

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Bat blitz!

How hard does a pallid bat bite?

How hard does a pallid bat bite?


Leith & Rochelle headed up to Canada last weekend to help with a Bat Blitz. This year, the objective was to inventory the bat diversity within a Nature Conservancy preserve in the Okanagan valley of British Columbia.

Over three nights, we documented 10 of the 14 species known to occur in the area. On the last night we participated, we finally caught a pallid bat – a rare and exciting catch. These bats are known to feed on large ground dwelling arthropods, including scorpions, and sometimes even small lizards! How much force is needed to access such hard prey items? Even though a few of the biologists felt force of this pallid’s bite, when we attempted to measure his bite force he was unwilling to perform.

While we had to leave the following morning, the blitz continued another night, and we hope they were able to document more of the diversity of this valuable preserve. We can only hope the next time we catch a pallid bat, the first thing he will chomp down on is our bite force meter!


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New NSF grant to study bat-plant coevolution!

We are thrilled to announce that our NSF collaborative proposal has been awarded! Together with the Dávalos lab at SUNY Stony Brook and the Riffell lab at UW, we will be working on the project “Chance or necessity? Adaptive vs. non adaptive evolution in plant-frugivore interactions”. We will investigate the coevolution between fruit scents and the olfactory ability and behavioral preferences of fruit-eating bats by integrating advanced tools from analytical chemistry, genomics, and behavioral ecology. Our work will focus on two ecologically important groups of tropical plants and mammals, Piper plants and Carollia bats, and will be based at La Selva Biological Station in Costa Rica. We are currently looking for a postdoc and recruiting a Ph.D. student for this project.

Photo © Merlin Tuttle, BCI

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Notes from the Field: Moses Coulee

Rochelle, Jeff and I  headed out to Moses Coulee to catch bats in the shrub-steppe. The primary goal of this trip was to be guest researchers for an Urban Conservation course through the Doris Duke Conservation Scholars program. We took the students out mist-netting and showed them what it was like to be a real bat researcher. Even though time was limited, we had success the first night out! We caught two amazing species, the Canyon bat (Parastrellus hesperus) and the Townsend’s big-eared bat (Corynorhinus townsendii). This group of students was extremely interested in many aspects of bat research: from managing museum collections, to emerging research and basic biology of bats.  

This excursion also allowed us to set up some of our new equipment, a triple high mist-net that Rochelle and I lovingly named “Monster”. We ventured out for a second night of mist-netting, “Monster” in hand,  with the optimistic hope of catching a Spotted bat (Euderma maculatum). We did not succeed in netting a spotted bat, but we did catch a Pallid bat (Antrozous pallidus) which was also very exciting! Overall this was a successful trip for us to see the diversity of species in a different part of the state and to help spread awareness about bat ecology, conservation and research.



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Notes from the field: Vendovi Island

Gearing up for this summers’ field work! Last week Sharlene, Abby, Jim and I set out to conduct a pilot survey of the bats on the Vendovi Island preserve. In collaboration with the San Juan Preservation Trust, a local non-profit land trust, we carried two nights of surveys to begin documenting the bat diversity on this 217 acre island. This was an excellent opportunity to help the trust in their broader efforts to document the biodiversity on this island preserve. It was also a valuable opportunity for me to kick start my research on the San Juan Islands, which I will be starting in July on San Juan and Orcas Island.

Over our two-night survey, we captured bats 2 of the 10 species documented to occur throughout the archipelago. Surprisingly, all of the bats we caught were males. So, is Vendovi Island a bachelor pad for bats? Our surveys were too limited to say for now. I hope to return later in the season, as maternity colonies begin to form to assess whether females, and other bat species also inhabit the island. For more information about the biodiversity of Vendovi Island or the San Juan Preservation Trust, click here.

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Bat of the Week: Antrozous pallidus

Common name: The Pallid bat

Photo Credit: Top: Merlin Tuttle, bottom left: American Natural History Museum, bottom center:, bottom right: J. Scott Altenbach

Photo Credit: Top: Merlin Tuttle, bottom left: American Natural History Museum, bottom center:, bottom right: J. Scott Altenbach


Where to find them: This widely distributed species, along the west coast of the North America, has a range from southern British Columbia through Montana to central Mexico.

Roosting: The pallid bat roosts in a variety of places but favors rocky outcrops.  They can be found roosting in anything from caves, rock crevices, mines, hollow trees, to buildings. At night they choose temporary roosts for resting between feeding bouts that are near, but different from, day roosts.

Diet:  A. pallidus is an insectivorous bat and has a unique foraging pattern among North American bats. They fly very close to the ground, then dip down to grab ground-dwelling prey. This bat has extremely good hearing  and the foraging strategy allows bats to use passive hearing to find prey moving on the ground. They may also make contact with the ground to grab larger prey. They also forage for insects among leaves and flowers. Additionally, they will take smaller prey in the air using echolocation. Pallid bats take larger prey back to their roosts and remove hard parts, such as wings, legs, and heads, from prey before consuming them.

Unique traits: Pallid bats use vocalizations to locate other members of their group. There are four main call types used to communicate with other individuals: a directive call  is used to find another individual, a call consisting of squabble notes tells bats how to space themselves when roosting, a buzz call used for intraspecific encounters, and ultrasonic  pulses for  orientation and communicating exploratory activity to other individuals. Another unique trait is how agile they are on the ground; they are good at crawling and climbing.

Recent research:  Barber tested if A. pallidus is able to process two different streams of auditory information simultaneously while hunting. This research shows that pallid bats behaviorally modulate their echolocation calls to be able to switch focus between two streams of auditory information, but cannot truly dually orient themselves via echolocation and listen to insect movement. (Barber et al., 2003)

Information from


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Bat of the Week: Nyctimene albiventer

Common name: The common tube-nosed fruit bat

Photos are not of N. albiventer, but of related species. Photo credit: Right: Bernard Van Elegem, top left: Alexander Riek, bottom left:

Photos are not of N. albiventer, but of a closely related, similar looking species. Photo credit: Right: Bernard Van Elegem, top left: Alexander Riek, bottom left:

Where to find them: Halmahera Islands, Banda and Aru Islands, Bismarck Archipelago, Moluccas, New Guinea, Admiralty and Solomon Islands and the Cape York peninsula of Australia.

Roosting:  The common tube-nosed bat roosts individually on the trunk of trees or branches. Their wings are covered with irregularly sized and spaced, yellow spots that act as camouflage while they roost.

Diet:  N. albiventer is primarily frugivorous, however it may also eat nectar and insect remains have been found in the stomachs of a few specimens. To eat fruit, the bat will hang horizontally biting off small chunks of fruit.

Unique traits: This bat has a unique face, with long tubular nostrils and very large eyes. The function of the tubular nostrils is unclear, however they could aid in finding fruit through olfaction or be used in the production of sound as the nasal tubes stretch and vibrate when the bat emits a high whistling call.

Recent research:  N. albiventer has been of interest in various feeding studies. One study documents the fruit handling behavior in both Old World (Pteropodidae) and New World fruit bats (Phyllostomidae).  While there is variation in the fruit handling behavior among all bat in this study, N. albiventer primarily held fruit with their stomach as opposed to with their wings, like most New world fruit bats (Vandoros & Dumont 2004).

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Bat of the Week: Thyroptera tricolor

Common name: Spix’s disk winged bat

photo credit: Top left: Christian Zielger, top right: Brock Fenton, bottom left: Alan Henderson, bottom right:

photo credit: Top left: Christian Zielger, top right: Brock Fenton, bottom left: Alan Henderson, bottom right:


Where to find them: Southern Mexico to the South Eastern Edge of Brazil

Roosting: Spix’s disk winged bat roost in the partly unfurled leaves of trees of the genus Heliconia (palm). Their roost colony size is about 6. These bats change roosts often, every day or so, because as leaves mature they unfurl and are no longer habitable roosts.

Diet:  T. tricolor is an aerial insectivore, catching insects while in flight. It consumes about 1 gram of insects a day, including beetles and flies. 

Unique traits: At the base of their thumbs and ankles is a disk-shaped suction cups that they use to cling to the  Heliconia leaves in which they roost. One of these disks is strong enough to support the bat’s entire weight. They also posses “warts” on their noses, it is hypothesized these “warts” are extra sensory organs.

Recent research:  T. tricolor uses call-and response systems to find group members. Flying bats can discriminate between the inquiry and response calls emitted by group and non-group members (Chaverri 2012).

Information from

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Bat of the Week: Micronycteris microtis

Common name: Common Big-eared Bat

Photo credit: Left: Christian Ziegler, top right: Inga Geipel, bottom right: Santana et al. 2011

Photo credit: Left: Christian Ziegler, top right: Inga Geipel, bottom right: Santana et al. 2011


Where to find them: Southern Mexico, Central America, and the northern half of South America.

Roosting: Common big-eared bats roost in small groups of 4-6 in a variety of structures, including hollow trees, logs, caves, culverts, buildings, and animal burrows.

Diet: M. microtis is a diverse animalivore that gleans all kinds of insects, from beetles to dragonflies to caterpillars. The known prey species of these bats span 12 different orders of arthropods. In addition, it has been observed to kill and eat small lizards, making it the smallest known carnivorous bat.

Unique traits: To manage the different mechanical properties of its diverse array of food, the skull shape of M. microtis appears to have rapidly evolved in order to maximize its mechanical advantage and it can easily modify its biting behavior when eating prey of different  hardness (Santana et al. 2011).

Recent research: M. microtis can use echolocation to detect and capture completely silent and motionless prey even in acoustically cluttered environments without relying on olfactory or visual signals–a feat previously thought impossible (Geipel et al. 2013).

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