Vampire bats: Social groups share a common microbiome

Vampire bats form tight social groups and even share regurgitated food – and doing so means the bats end up with a similar gut microbiome

By Christa Lesté-Lasserre

Microbes may be transferred between vampire bats when they lick and groom one another and share regurgitated food – and this means the bats living together end up with a common “social microbiome”.

What’s more, within each colony, the more one bat touches another with its mouth and tongue – a sign of how socially close the pair are – the more the pair’s microbiota align with one other, says Gerald Carter at the Ohio State University in Columbus. “Their relationships map right onto their microbiome similarity.”

Carter and his colleagues ran DNA sequencing on faecal samples from common vampire bat (Desmodus rotundus) colonies in six US zoos and one wild colony in Belize. They also took faecal and inner gut samples from an experimentally grouped colony of bats, which originally lived in three separate wild colonies in Panama and were then housed together for four months. For this last group, they also ran infrared video recording for six hours a day throughout the experiment to observe social contacts, especially licking.

Bats living in the same colony – whether in the wild or in zoos – typically had gut microbiomes that were similar to each other and dissimilar to those from other colonies, in terms of the microorganisms present and their relative abundances, says Carter. Despite living together for only four months, the microbiomes of bats in the experimentally merged group were also similar to each other, but less so than those in the natural colonies in zoos and in the wild. The more physical – and especially oral – contact there was between any two bats in that colony, the more similar their microbiomes were.

The findings suggest that while bats might get their gut microbiota from their parents, their environment and their diet (which is exclusively blood), their microbiomes can change easily and rapidly to line up with those of bats in their social community, says Carter.

That could be partly due to their intimate social contact, he says. In addition to spending 5 per cent of their time grooming each other, vampire bats feed baby bats and sick bats with regurgitated blood – which probably also “inoculates the guts” of these individuals, says Carter.

More than three quarters of the microorganisms in the bats’ gut microbiomes came up with no matches in genetic bases, meaning they might be unknown to science and are possibly unique to vampire bats, he says.

“Microbial sharing has to be really important for these bats, and their [unique] microbes may be helping them digest blood in some way that we don’t yet understand,” says Carter.

Journal reference: Biology Letters, DOI: 10.1098/rsbl.2021.0389

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