Research
Photo Credit: Charles Francis
Bats are social mammals that live in large groups ranging from a couple dozen to millions of individuals. Close knit animal groups can form dominance hierarchies in order to reduce aggression over shared resources. These hierarchies are characterized by a ranking based on access to resources. The potential for hierarchical structures within bat social groups has not been widely studied despite there being anecdotal evidence of hierarchical structures within various species of bat. One reason for the lack of focus on this question is the fact that many bat species live in fission-fusion groups, where the group composition varies daily. In our study we focused on Carollia perspicillata, which is a harem forming species of bat with female groups ranging between 5-18 females. In this study, we observe Carollia sp. within all female groups to determine if a dominance hierarchy will form based on roost position. The center of the roost is preferred by females due to greater thermoregulation. We took video and audio recordings and quantified by time spent at roost position, aggressive interactions, and social calls between the females. Ongoing analysis aims to explore the hypothesis that female groups of Carollia sp. follow a near-linear dominance hierarchy, with more established females having better roost positions than juveniles or newcomers.
|
Though bats are well known for their highly developed audio-vocal system, far less attention has been placed on their olfactory abilities. Like mice, bats’ brains have, and oversized representation dedicated to smell, their olfactory bulbs can account for about 10% of the mass of the brain, while for humans this number is an order of magnitude less. Furthermore, several bat species have been found to have secretory glands that they use for social interactions, by rubbing the secretions on each other and on trees and roosting sites. Few experiments have looked at the olfactory capabilities of bats and have mainly focused on the use of olfaction for sensory integration during foraging. To our knowledge, only one lab has looked at the social preference of bats through olfactory queues and this research investigated the hormonal state of Eptesicus bats’ social preference . Moreover, no experiment yet has looked at the microbial contribution to odorants and the neurobiology of olfaction in bats. Here, we propose to expand on this knowledge two-fold. Firstly, we will carry out a set of experiments during the field trip in Belize in 2023. Secondly, that data will be published and will be used to submit a grant that will enable laboratory experiments that can delve into the neural circuits underlying olfactory social preference.
|
Bats are social mammals that display a wide array of social communication calls. Among them, it is common for most bats species to emit distress, agonistic, appeasement and infant isolation calls. Big brown bats (Eptesicus fuscus) are no different: They are gregarious animals living in colonies that can comprise hundreds of individuals. These bats live in North America and, typically found roosting in man-made structures like barns and attics, are considered common. A call that has been described in E. fuscus is the frequency modulated bout (FMB), which serves as a food claiming call. If two bats in flight are approaching the same prey item and one emits an FMB, the other will leave that prey item. This experiment puts two individual bats in a small enclosure with a bowl of meal worms in order to have them compete for food. Ongoing analysis is exploring the hypothesis that bats are more likely to react to a call when in a social context as opposed to when listening to a playback.
|