Excerpts

Bat Senses Hearing & Echolocation: It must be fantastic to fly in total darkness with your ears and without the use of your eyes. This is exactly what bats are capable of doing. Even though bats have average eyesight, the insectivores detect insects, obstacles, other bats, and many other things with the information that their specialized ears detect. Have you ever noticed the large size or the unusual shapes of bat ears? The ears are designed to receive the echo from the sound that bats send out with their mouth. The echoes give the bat all the information it needs to chase an insect or maneuver in flight. Bats can detect shape, size, speed, distance, and just how juicy an insect is from these echoes. The echoes travel to the brain and reveal all kinds of helpful information to make a bat successful. Echolocation is actually sonar. The majority of the sounds are high-intensity, and we cannot hear them with our ears. Some bats emit sounds that are low-intensity, and humans can hear those sounds. These types of bats are called whispering bats. The sounds go through a cycle from slow to fast depending upon the phase of the hunt. In the beginning, bats produce 25 sounds per second when in the search phase. If the bat locates an insect (approach stage), the sounds speed up to 50 per second. Then during the killing or terminal stage, the sounds are produced at 100 per second or greater! This last stage is called the "feeding buzz," as all of the sounds run together in a buzz. All along, the bat is processing this information in its brain, much like a computer processes data. Their amazing ears channel the echoes to their amazing brains! Echolocation may also help bats communicate with each other. Bats that don't use echolocation, such as nectar and fruit bats, do not have specialized ears. These bats primarily orient by vision. Vision: "Blind as a bat" does not apply to the amazing bats. Bats can see just fine, and eyesight is utilized for flying, orientation, distinguishing landmarks, and during migration. Bats that echolocate have small eyes, whereas bats that do not utilize echolocation have large, prominent eyes. Bats with large eyes are flying foxes (fruit bats) or nectar bats, and their vision is well developed. These particular bats feed on plants, nectar, and fruit, and they need their large eyes to find their plant food. Bats with small eyes would not be able to follow or forage on insects in total darkness without echolocation, so their vision is not as developed as bats with large eyes. Many bats do not have cones in their eyes for color vision, but since insectivorous bats are nocturnal, they don't need color vision. Fruit and nectar bats have cones in their eyes to see color, and many are diurnal in behavior. Smell: If you ever venture into a mine or cave that houses numerous bats, you will immediately smell urine or feces. How do bats live in such an environment? Bats have a very high tolerance for these smells and don't seem to mind the strong odors. Smell is important for distinguishing prey (good and bad tasting), as well as for courtship and reproduction, mother and young interactions, social communication, and locating plant food. Excerpted from Bat Basics: How to Understand and Help the Amazing Flying Mammals by Karen Krebbs All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.