During their history, bats have evolved wings and powered flight, extremely long lifespans, the ability to tolerate viral infections, and echolocation. They have UV vision, saliva-borne anticoagulants, novel structures, and diverse diets. Bats therefore are “natural evolutionary experiments” that we use to study questions of relevance to evolutionary processes and human health.
Our research includes bat populations in Puerto Rico, the Dominican Republic, Trinidad and Tobago, Belize, Cameroon, and the Philippines. In all of these locations, we work with local scientists to study the unique traits of the bats of the region.
Bats have explosively diversified to fill many ecological niches, and today there are over 1200 bat species! Below we describe three of the many unique adaptations in bats that we are studying in the lab.
Only 19 species of mammal are longer-lived than humans, relative to their body size, and 18 of these are bats. Bats are also the longest-lived mammals, given their body size, with the oldest wild bat (Myotis brandtii) living to at least 41 years — 10 times longer than predicted given its size! Despite their long lifespans, bats seemingly do not “age” like humans; bats remain healthy and fertile even into advanced age.
Bats eat all kinds of foods, with diets ranging from fruit to nectar to arthropods and other vertebrates — even blood. These diverse diets are enabled by an equally diverse range in the teeth and hard palates (i.e., the bones on the roof of the mouth) of different bat species. For example, bats that eat hard fruits have short and wide palates that allow them to generate strong bite forces, and fewer but larger teeth. Bats that feed on nectar have very long and narrow palates to support their long tongues, and more teeth that are all similar in size. These food-driven adaptations have led to unique facial morphologies across bat species.
Bats are the only mammals capable of powered flight. This flight is made possible thanks to a suite of adaptations in their front limbs. Bats have several wing membranes that act as air foil for flight. Some of these membranes are retentions of embryonic structures (e.g. the webbing between the fingers) while others are truly novel structures that have no direct precursors in the bat ancestor (e.g. the webbing between the bat rear legs and the pinky finger and the body). Bats also have extremely elongated fingers to support these wing membranes: if we were bats, our fingers would be as long as our whole bodies!
Bats are also among the longest-lived mammals for their body size. However, bats seemingly do not physically age. We want to understand how bats achieve these incredible biological paradoxes.
To solve this riddle, we are currently working to understand the links between aging, the immune response, and cell biology in bats from Cameroon in western Africa. When in Cameroon, we work with the Congo Basin Institute (CBI) of UCLA. We first focused on bats from Cameroon because of their great diversity, status as important carriers of many viral zoonoses, close interactions with local people, and proximity to some of the most severe zoonotic cross-over events of the past century (e.g., Ebola, Marburg). More recently, we have expanded our research to include the diverse bats of the New World, including vampire bats, in our studies of zoonoses and aging.
Our research in bats has potential to:
Improve models of bats’ key roles as reservoir species for emerging deadly zoonoses
Inform human health challenges in aging and infection
Uncover developmental rules that have shaped the evolution of form in mammals
Reveal how completely novel traits arise in mammals
Bat wings are basically giant hands
For decades, scientists have explored how the front limbs of the bat ancestor evolved into bat wings capable of powered flight. Our results suggest that, early in development, the bat wing is actually similar to the front limb of quadrupedal animals, like a mouse. Bats then alter the expression of key limb genes and pathways to generate a much larger limb with longer digits.
Loss of colored vision in bats
Few people are aware that bats have good night AND day vision. Some bats can even see colors thanks to two proteins in their eyes: S-opsin which detects blue/UV light and L-opsin which detects green/red light. Many bats, however, are missing S-opsin and therefore cannot distinguish colors. We found that S-opsin has been lost >12 times in our bat group.
Evolutionary rules & bat teeth.
A long-standing question in biology is why some morphologies have frequently evolved, while others – though theoretically possible – seemingly have never evolved. We are going to use bat teeth to help answer this important question. We have just been awarded an NSF grant to study the “Role of developmental bias in the morphological diversification of bat molars.”
