Microbiome Monday: Animals and Their BFFs

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It's Microbiome Monday again! Before the Museum’s upcoming exhibition The Secret World Inside You opens November 7, we’re offering weekly primers on the microbiome and the research surrounding it from Curators Rob DeSalle and Susan Perkins, as well as from other scientists who are working in this exciting field.

Dr. Valerie McKenzie's lab at the University of Colorado is looking to learn more about the microbiomes of non-human animals. Shedding light on these ill-understood relationships could help us cure diseases that are wreaking havoc on animal populations around the world.

How Oddball Friendships Evolved

A quick YouTube search will turn up around 15,000 videos documenting oddball interspecies friendships. Among the cats and dogs who have made peace and foxes cuddling up to ducks, there’s one connection we don’t see: that between animals and their microbes, the oldest and most intriguing relationships between species there is. This oddball friendship between animals and microbes, which has existed since animals became animals, continues to shape their evolution and ecology.

Dogs, cats, and even microbes can all live together in harmony.  Courtesy of picturetoburn.tumblr.com

Dogs, cats, and even microbes can all live together in harmony. 

Courtesy of picturetoburn.tumblr.com


Early single-celled eukaryotes, the domain to which animals belong, fed on bacteria at first. Eventually, some 600 million years ago, bacteria were able to live inside eukaryotic cells in mutually beneficial symbioses, creating new opportunities for both. These are the relationships explored in our lab at the University of Colorado.

From these humble beginnings, microbes and animals continue to forge partnerships and collaborate in physiological and ecological functions. Microbes make digestion possible and allow animals to use a variety of resources, sometimes in unexpected ways; for instance, microbial populations allow hydrothermal vent worms to use sulfur in the deep sea, and power the migrations of whales.

Dr. McKenzie's lab wants to learn if the microbiomes of vampire bats are as specialized as their teeth. Courtesy of Wikimedia Commons

Dr. McKenzie's lab wants to learn if the microbiomes of vampire bats are as specialized as their teeth.

Courtesy of Wikimedia Commons


Our lab is studying animals with highly specialized diets such as blood-feeding finches, vampire bats, and leeches. While these animals look very different on the outside, our research team team is studying whether they have similar gut microbes that help them digest their bloody meals. Together with collaborators like Dr. Jessica Metcalf and Dr. Se Jin Song, we aim to shed light on how the ancient collaboration between animals and their microbial BFFs evolve solutions to specific biological challenges like this one.

Other projects we're investigating include beneficial microbial partners that protect animals from harmful pathogens, including a fungal pathogen that attacks amphibians and another that is devastating bat populations. We're in the process of learning what role the microbiome could play in conservation efforts. 

CU Boulder graduate student Christine Avena gathering microbial samples from bats in the field. © C. Avena

CU Boulder graduate student Christine Avena gathering microbial samples from bats in the field.

© C. Avena


Right now there are more questions than answers, but if we know something about animals and their microbes, it’s that these oddball inter-domain friendships sometimes make the improbable possible.