I know I wrote a piece on bats not to far back, but I attended a talk on bats from the Texas Dept of Parks and Wildlife and it was too interesting not to cover.
Bats are of the order Chiroptera. There are two branches: megachiroptera and microchiroptera. In Texas we have only microchiroptera bats. There are over 45 known species of bats, 33 of which reside in Texas. Of those 33 bat species residing in Texas 31 live on insects, 2 live on nectar. The nectar eating bats live along the Rio. 11 species of bats reside in Houston and all those in the Houston area are bug eaters.
Bats are mammals and live an average of 41 years. They are the only true flying mammal. The wings have a stretchy material between the bones which is what allows them such maneuverability when flying.
There are three species of vampire bats. All of which reside in Latin America. They feed on the blood of sleeping animals. The bats noses have heat sensors to help locate victims. The vampire bats have very strong legs allowing them to leap. Fangs are in the center of the top row of teeth, like buck teeth. They punch a tiny hole in the victim and lick the blood as it comes out. The blood has an anti coagulant to stop the bleeding. They drink about a teaspoon of blood a night.
Bats are protected by state law in Texas it is illegal to harm them. Bats in Texas range from 2″ nose to tail to 6″ nose to tail.
Bats flying low to the ground should be avoided. Less than 1/2 of 1% of local bats have rabies. But those that do get weaker and weaker and fly closer to the ground the sicker they get. Sometimes babies that are just learning to fly will fly close to the ground. They are not rabid.
Bats do have sight but rely mostly on echolocation to find prey. They send out a high pitched sound and listen for the bounce of that sound.
Many local bats live in the leaves of trees. They hang upside down in the tree and look just like a leaf unless you look very closely. They especially like to roost in the dead palm leaves in our date palms here in the Houston area.
Young bats are born between late May and leave the nest in early Aug. The dept. of Game and Wildlife asks that you not trim off your dead palm leaves until late Aug. to protect young bats.
While sleeping bats body temperature drops and they shiver upon waking to warm up. They must warm up before they can fly. If you startle a sleeping bat it make take the bat a few minutes to warm up enough to fly away.
The Big Eared Bats are a threatened species. They eat bugs.
Northern Yellows roost in Spanish moss and more recently dead palm leaves.
Eastern Reds roost in leaves, loose bark and tree hollows. Some of these ones hibernate in cooler weather. They live as a family until the young leave then live solo.
Big Browns live in small colonies and a huge bug eaters locally.
Mexican Freetails are the most common in Houston. They live in large colonies. The babies sleep communally to keep warm as they are born hairless. They remain in large colonies their whole lives. The Mexican Freetails have two nightly cycles of feeding. The first is done close to the ground after which they rest. The second is done about 10,000′ up where they feed on migrating moths coming from Mexico and prevent them from destroying crops up here.
The Waugh Bridge in Houston has a year round large population of bats who leave enmass at dusk each evening. They roost in the I-Beam construction bridges. The Congress Ave bridge in Austin has an even larger population living there.