Certain bat females and males get on each others nerves so much that they create their own homes where adult members of the opposite sex are not allowed entry.
Some of the male bats were found in spotlessly clean “bat bachelor” pads.
Certain female bats, along with their offspring, were found in slightly messier roosts (due to the kids) in less windy locations.
“One possible reason for not finding males … is that the mothers just want to avoid competing with males for food,” project leader John Altringham from the University of Leeds’ School of Biology said in a press release. ”It takes a lot of insects to make the milk needed to feed their young.”
“But it is also possible,” he continued, “that the males choose not to roost with the females. Mothers and pups often have a lot of ectoparasites like ticks and mites. In a warm, crowded nursery, parasites can thrive. Parasites not only make life uncomfortable but can affect a bat’s health. The males that live by themselves are usually very clean in their bachelor pads, so you can understand why they might not want to move in.”
This seems to be a personal choice — not all Daubenton’s bats live in separate housing. Altringham and his team found a “small oasis of cohabitation in Grassington,” a nearby town.
“They have these warm, cuddly males to bunk up with. This way, females use less energy keeping warm and babies grow faster,” Altringham said. “In these marginal conditions, they may just tolerate a few males to keep them warm. Otherwise they kick them out. Why do the males co-habit if they are going to get parasites all over them? Well, that may be down to the usual answer: sex.”
Bats therefore face some of the same challenges that we do, in terms of finding good mates and real estate, and dealing with messy children. And they also have their doting dads, resourceful females and confirmed bachelors.
“At Grassington, most of the fathers of bats born there spent the summer with the females,” Altringham said, adding that females only produce one pup a year.
“If we look at pups in [other nearby spots] their dads were males caught when swarming at caves. So, as well as two different mating systems, you have distinct social groupings. A bachelor from Buckden is always a bachelor from Buckden. He doesn’t pop down to Grassington to visit the females in the summer. His only option seems to be to go clubbing in the autumn.”
Image: Daubenton’s bat. Credit: Gilles San Martin