Kimberly J. Workinger
The genes are the set of instructions which builds the parts of the body, including the brain. Each species brain is built on a somewhat different pattern. When a happy, a dog may wag it’s tail, a cat purrs and a human smiles while a turtle shows no outward signs at all. These differences are due to the different brain structures inherent to each species. The brain and other parts of the nervous system generate behaviors with a response to environmental input and hormones. Some of the behaviors may be simple immediate responses to simple stimuli including the knee jerk reflex and the cry of pain and grimace when an animal is hurt. There are also automatic responses to more complex situations like the tail wagging and the smiling mentioned above or uncontrolled laughter and giggling. Other behaviors are driven from internal motivations like hunger, thirst, need to sleep, defecate, urinate, sex drive, etc. Some are extremely complex like birds migrating thousands of miles to find winter nesting grounds or human children learning to speak. These behaviors are all intimate interactions between the propensities and capabilities of the brain and the environment in which the individual exists.
The word instinctual refers to the contribution of the brain’s structure to a behavior. Eating and sex are clearly instinctual- but an animal cannot eat if there is no food and can’t mate if there is no partner available. Bird migration is called an instinct, but its direction is guided by patterns in the stars. The development of human speech is called learning- but every human child can do it without explicit teaching. The brain need to pick up language by hearing others speak.
The different species have evolved behaviors that help it succeed in its own environment. Fish have evolved fins and swimming behaviors and mammals have evolved legs and walking behaviors. Many animals communicate with each other and other animals. Birds have evolved singing, dogs barking, cats meowing and humans speaking. All of these species also communicate using visual cues-coloring of birds, facial expressions in many animals, ear, face and tail position in dogs and the crouching position of cats.