Inheritance: In the book The End of Stress as We Know It,* Dr. Bruce McEwen explains that wild zebras do not develop gastric and duodenal ulcers† despite the fact that their daily lives are extremely stressful. For example, zebras frequently get chased by lions. During the chase, zebras become very stressed, however, the minute they either escape or get caught, they simply relax! Because of their genetic makeup, their environment, and the way they adapt to their environment (experience), zebras respond to this stress in a way that is different than how humans would respond. This simple example can be extended to many other areas of behavior, including communication.

Animal communication: Most animals (including people) use "body language" as well as sound and smell in order to communicate with one another. Here are some of the ways animals express themselves. Many animals communicate by smell: they release pheromones (airborne chemicals) to send messages to others. Pheromones play an important part in reproduction and other social behavior. They are used by many animals, including insects, wolves, deer, and even humans! Communication is so important that even the amoeba (an organism made up of a single cell) communicates with other amoebas by chemical discharge. By doing this, one amoeba attracts others to it for reproduction. Bees dance when they have found nectar. The scout bee will dance in the hive, and the dance directs other bees to the location of the nectar. Chimpanzees greet each other by touching hands. Male fiddler crabs wave their giant claw to attract female fiddler crabs. White-tailed deer show alarm by flicking up their tails. Dogs stretch their front legs out in front of them and lower their bodies when they want to play. Elephants show affection by entwining their trunks. Giraffes press their necks together when they are attracted to each other. Gorillas stick out their tongues to show anger. Kangaroos thump their hind legs to warn others of danger. Prairie dogs bare their teeth and press their mouths together to discover if they are friends or foes. Whales breach (leap out of the water) repeatedly to send messages to other whales. Swans entwine their long necks both to fight and to court. Horses rub noses as a sign of affection. These forms of communication are affected and influenced by the genetic make up of a species, their own environment, and their experiences. Communication abilities in most animals can be further developed depending upon their environment. For example, animals living in a circus have a larger set of communication skills than those living in most homes, because they are exposed to an environment that offers new opportunities for both learning and training on a continual basis.

*The End of Stress as We Know It, Bruce McEwen with Elizabeth Norton Lasley, The Dana Press, Joseph Henry Press, Washington, D.C., 1st Ed., 239 pp., 2002.

†Ulcers, which are common in humans, occur when the inside of the stomach or the intestines becomes extremely irritated and inflamed.