Blog: Mysterious flying mammals

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Bats

The mysterious bat symbolizes the remarkable diversity of wild animals within California and across America.

There are at least 25 bat species in California that make remarkable pest managers since they devour insects. Two common fallacies need to be dispelled: first, bats are not blind, even nocturnal bats have excellent eyesight; second, the superstitious lore of a blood sucking creature is unwarranted and, in most bat species, untrue.

There are more than 1,100 kinds of bats worldwide and live on every continent except Antarctica. Most bats rely on insects as a food source, others on fruit; only a few species attack other animals.

Bats are the only mammal capable of flying. Their wings consist of a double membrane adjoining a bony structure resembling a human hand. The extra long fingers and membrane run downward to include a tail. Their thumb claws are used for climbing and turning around during roosting or perching hanging upside down.

When most animals hang upside down blood rushes to the head, but not in bats. They have special valves in their veins to keep the blood moving through their bodies when inverted. 

How much energy do bats use for flying? Lots. California bats flap their wings between 10 and 20 beats every second and can reach speeds of between four and 22 MPH. In order to achieve these astonishing speeds their heart must pump at about 1,000 beats per minute. 

Bats have learned to compensate for high energy needs by lowering their body temperature. Because they have an internal adjustable thermostat when their inactive body temperatures fall from 113 to 41 degrees Fahrenheit. Their heart rates drop from 200 to 100 beats per minute while resting and down to five beats per minute during hibernation. 

To hibernate bats must have a 40 percent fat reserve. It’s a good thing that bats are excellent hunters. One bat can eat up to 600 mosquitoes in an hour! They also feast on moths.

To catch insects, bats use echolocation, or sophisticated sonar, to locate their prey. In addition, bat sonar enables navigation with ease in total darkness. When high frequencies are emitted from the voice-box a bat’s sensitive ears can hear echoes and their brain easily differentiate between trees, rocks or prey.

The next time you have a campfire at dusk, notice the flying activity overhead it’s our friends the bats, hunting their prey.

All nature’s creatures have marvelous adaptations and moths are no exception. They have evolved fine hairs which detect bat sonar. When a bat hunts for a moth it is analogous to high-tech warfare between modern fighter jets. Moths are able to zig-zag and free-fall like  skydivers. When moths free-fall, bats somehow calculate the angle of incidence, making a pouch using their tails to form an inverted scoop, often catching their prey. And once caught, they rapidly chew-up the moth,  seven times per second.

Bat populations are alarmingly dropping throughout California. Predators include snakes, hawks, owls, cats, raccoons, skunks and weasels. Human activity has inflicted by far the most detrimental impact on bat populations in California, throughout the U.S. and worldwide.

These mysterious flying California mammals are truly incredible critters, most worthy of admiration and protection.

Earth Dr. Reese Halter is a broadcaster, conservation biologist and author of “The Insatiable Bark Beetle.”