Book II. Valley of Fi

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1. Are bats related to birds?

No, bats and birds are not related, even though both can fly. Birds are in the class called Aves and have feathers, while bats are mammals.  Bats are warm‐blooded, have hair, bear live young, and mothers feed their babies milk through nursing. 

2. What animals are bats most related to?

A bat’s closest relative is a shrew, a small mole-like animal. Like bats, shrews are mammals, feed on insects, are nocturnal, some even use very basic forms of echolocation. The oldest know complete fossil record of a bat is from the Eocene period, over 30 million years ago. 

3. Name animals that use sound waves to communicate.

In addition to bats, a number of animals use echolocation (soundwaves) to navigate, communicate, and find prey in the dark. These include whales and dolphins, allowing them to ‘see’ in muddy or dark waters, shrews, hedgehogs, and birds in the swift family that use echolocation to find their way out of dark crevices where they roost.

4. Where can you go to see bats?

Watch for bats in the evening, especially around lights, such as at evening ballgames, where they maybe foraging on insects such as moths that are attracted to lights. However, some bats species are light sensitive, and avoid bright lights, so soft outdoor lighting that minimizes light pollution is healthier for bats. Places to watch bas emerge from their roosts in the evening include Austin, Texas, where a million Mexican free-tailed bats live under the Congress Avenue bridge during the summertime. In California, the Yolo Causeway near Sacramento also has a large bat roost where visitors can watch bats emerge from their roost via guided tours through the Yolo Bypass Wildlife Area.

5. Can bats stand on their feet?

No, bats cannot stand on their feet like a bird because their legs and feet were built for hanging, not for standing up, so they lack the needed muscles for standing. They can ‘walk’ on their elbows with their wings shut, using them like walking stilts to get around the ground. Vampire bats are particularly adept at running around on the ground on their elbows. Without strong legs for standing, bats have a hard time taking off from the ground. Bats will flap their wings until they get enough lift to rise off the ground. Other times they’ll use their thumbs as claws to scoot around on the ground and climb structures to get higher up and then will fly away. Pinta, the pallid bat hunts for insects and other critters on the ground and can readily take off from the ground. To drink, bats fly over open water, scooping water into their mouths, like swallows.

6. Why do bats hang upside down?

Hanging upside down in roosts keeps bats safe from predators. No one can get to them on a ceiling on a cave. Bats have specialized tendons that lock their toes and legs in place so that they are able to cling to the ceiling without expending any energy.  In fact, bats must flex their muscles in order to unlock their legs to let go of the roosting surface. These adaptations are quite helpful for a flying mammal since bats only need to let go of the roost in order to drop into flight, expending minimal energy. 

7. Where do bats go during the winter?

Some bats hibernate during the wintertime when it gets cold and there’s no insects to eat. During hibernation, a bat’s heartbeat slows down to about 10 beats per minute, compared to 300-400 beats per minute when it’s active. It’s important not to disturb bats when they are hibernating because if they wake up, they burn fat tissue, and then they might not be able to have enough energy reserves to make it through the winter. Other bats migrate south for the winter where there are plenty of bugs to eat. Some migrate thousands of miles from northern U. S. states and Canada down to Mexico and even South America, then come back the following spring. Where the weather is mild, such as California, bats might go dormant for a week or two, then come out for forage and drink water on a warm day.

8. What animals migrate besides bats?

Many animals migrate to find better places to live, eat, and have young in response to seasonal climate changes. This includes mammals, fish, reptiles, amphibians, insects, and crustaceans. Some animals hibernate during the winter in response to diminished food supplies, instead of traveling south where its warmer and there’s plenty of food to eat. Bats do both, with some species hibernating and others traveling south for the winter. Some travel as far south as Mexico and South America. If you find a bat out in the open where it is not supposed to be, sometimes it may be resting from traveling thousands of miles. Leave it alone, as long as no one can come in contact with it, and it’ll eventually fly away. It’s often the juvenile male bats that are careless, like roosting out in the open where they shouldn’t, which is why the mortality rate for juvenile male bats is so high.

9. What are the major predators of bats?

Lots of animals will eat bats, if they can find and catch them, including owls, hawks, raccoons, snakes, rats, and house cats. To avoid predators during the daytime, bats hide in crevices and loose bark under trees and roost on the ceilings of caves where predators can’t reach them. Bats are most vulnerable when leaving the roost, which is why they often emerge in groups, as there’s safety in numbers. At night, bats readily escape attacks by owls because they’re much faster and agile flyers, so it’d be hard for an owl to catch one. The biggest threat to bats is white-nose syndrome, a fungus that attacks bats in caves when they are hibernating. The fungus grows on their skin, including wings and faces, causing irritations. This causes bats wake up and then they burn too much fat tissue to make it through the rest of the winter, so starve to death.

10. Explain why bats are good.

Bats play an essential role in our world by helping to pollinate crops, disperse seeds, and they feed on insects, helping to control pests. Without bats we would not have bananas, cacao (cocoa), figs, mangos, or even tequila from agave plants, as bats are responsible for pollinating these crops in the wild. When bats feed on fruit, they ingest seeds that pass through their gut and out into the wild, helping to spread seeds. Without bats, farmers would be plagued with more insect pests attacking their crops. Bat guano is high in nitrogen, much needed for plant growth and commonly used as a fertilizer for crops. Scientists also study bats to better understand flight and sonar; they also study anticoagulants in vampire bat saliva to develop medicines that prevent blood clots in people.