My wife and I were recently discussing the Covid-19 pandemic, and the subject of bats came up. “What eats bats” she asked. Not much, I speculated. So I had to do a little checking up on bats.
There are over 40 bat species in the United State with 11 species documented in North Dakota. They are often associated with forested areas and riparian and other wetland areas, perhaps due to the abundance of insects associated with these areas. There are probably more bats around than most of us would realize.
The big brown bat and little brown bat are our most common bats and can be found across the state. Roosting sites vary between species, but in North Dakota common roosting sites include buildings, rock crevices, bridges, under tree bark, or in dead trees.
Predation on bats has not been well studied. Bats are generally protected in their roosts during the day, but it is a vulnerable period. Then at night when they are active, they are quite maneuverable. As such, they are difficult prey.
But some birds of prey, such as hawks and owls prey on bats, particularly when they enter or leave a roost in large numbers. And snakes, cats, and some other terrestrial predators may prey on young bats when they occasionally fall to the ground, for example when learning to fly.
A bat’s ability to avoid predators may be a factor in their longevity. Larger mammals generally have longer life spans. That is a broad generalization. But bats are a notable exception, with several species living to be 10-25 years, and some thirty years or more. That is about 3.5 times as long as other mammals of comparable size.
But all is not well for the bats. Their populations are declining across North America these days. A fungal disease, white-nose syndrome, is killing bats at an alarming rate. Plus, although the specifics are not well understood, wind turbines are taking a toll on bats.
So be on the lookout for bats this summer. Then give some thought as to how they can avoid predators and their secret to longevity.
-Chuck Lura
