Published: 12 January, 2000

Up to 9 bat species reside in N.Y.

How many species of bats are there? Why do bats live in caves? How big do bats get? Do bats go underwater? How long do bats live? Do bats mate and give birth while flying or hanging?

There are 9 different species of bats that live at least part of the year in New York. Some bats, like little brown and big brown bats, spend the whole year here and hibernate in caves and mines in the winter. Other bats, such as the silver-haired bat and the hoary bat, fly south for the winter just as some birds do. Bats that stay here year-round hibernate because they cannot find enough food to produce energy. The flying insects that they regularly feed on during the warmer months are not active during the winter. Caves and mines provide good places to hibernate because the temperature inside caves and mines usually stays relatively warm, from about 40-50 degrees all winter long.

New York bats are all fairly small. The Eastern Pipistrelle is the smallest bat in New York. It is 3 - 3½ inches long with a wingspan of about 8-10 inches. The hoary bat is the largest bet in the state. It is between 5-6 inches long with a wingspan of about 14½ - 16½ inches. The smallest bat in the world lives in Thailand and is called the bumblebee bat. This insectivorous bat has a wingspan of only 6 inches and weighs less than a penny. The biggest bat in the world, with a wingspan of nearly 6 feet, is the giant flying fox that lives in Indonesia. Although its wingspan is quite big, it only weighs about 2 ounces.

Although bats don't usually go underwater, they can swim out of a pool of water if they accidentally end up in one as long as they are able to grab onto something to get out. It is not unusual for them to drown in swimming pools or buckets of water though, because they can't get a grip on anything to help them climb back out. There are some bats that catch and eat fish, by dipping their feet down in to the water to catch them.

How long bats live is different depending on the kind of bat. For many kinds of bats, the life span is not yet known. However, the oldest bat caught in the wild was a little brown bat that was 34 years old at the time of capture! Bats live quite a bit longer than any other small mammals of similar size.

Female bats give birth to one or two pups during late May or early June, while hanging in their roost. The pups do not leave the roost until they are about 5 weeks old. However, mother bats leave the pups alone in the roost at night while they hunt insects nearby.