Vampire bats are the only mammals that can survive on a diet of just blood. In a study published on March 25, 2022, scientists have figured out the reason why — 13 genes are missing or no longer work in vampire bats, unlike in the genomes of 26 other bat species where the genes are still working. Those gene tweaks helped them adapt to a blood diet rich in iron and protein but with minimal fats or carbohydrates.
These "living Draculas," as said by study co-author Michael Hiller of Germany's Max Planck Institute, live in South and Central America and are about 3 inches (8 centimeters) long with a wingspan of 7 inches (18 centimeters). The bats bite and eat blood from livestock or other animals at night.
"It's totally bizarre and amazing that vampire bats can survive on blood — they are really weird, even among bats," said Hannah Kim Frank, a bat researcher at Tulane University, who was not involved in the study.
Another team of researchers also worked on pinpointing three of the 13 lost genes. It showed how different vampire bats are, even from other closely related bats, which eat nectar and fruit.
Vampire bats show their complex social relationships whenever they share their meals with other bats. Hiller said that well-fed ones vomit their food to share with a starving neighbor — they seem to keep track of who has helped them in the past.
"It's not a kin thing," added Frank. "They just notice and remember: You're a good sharer, I will reward you."
Image credit: Marco A. R. Mello