How do cows respond to internal and external stimuli?

Answer 1

A very loaded and highly generic and ambiguous question! A cow's response to such stimuli depends on what these stimuli are, because there is no one particular response for all types of stimuli they are subject to throughout their lives. Examples, however, may help in answering this question.

A cow will respond to internal stimuli in different ways. If a cow is feeling pain in her abdominal region, she will kick at it with her hind leg. If she is feeling the urge to urinate or defecate, she will often stop and hunch up her back, raise her tail and relax the sphincter muscles which hold the urine in her bladder and allow the urine to be expelled, often using her abdominal muscles to force the urine out faster and prevent it from sprinkling too much over her hind legs and hind quarters, including her udder. When she is done, she will lower her tail, even out her spine and continue with what she was doing. A similar response occurs when she feels the need to defecate: She will raise her tail, relax the sphincter muscles comprising of her anus, and contract her abdominal muscles to force the feces out into a nice, big steaming cow pie. After the deed is done, the sphincter muscles contract, the tail lowers, and she moves onwards. Other internal stimuli include a foreign object stuck in her trachea, which she responses to by coughing until it is free. If she is thirsty, she will find a water source and drink her fill. This is no different if she is hungry or craving salt or a mineral source.

External stimuli are more variable. A cow will respond to a frightening stimuli like a loud bang from a shotgun or a tractor that back-fired by jumping and running away. The presence of a coyote around her calf will get her "hackles up" and her guard up so much that she will make threatening gestures such as shaking her head, and charge at the beast to scare it away from her young.

Answer 2

An organism cannot live in isolation - it needs to be able to communicate with other organisms, either of the same species or of different species.

Communication is more evident in animals, although plants also need to communicate with each other at certain stages of their development. For an animal, communication can mean the difference between life or death. Animals have well developed nervous systems which allow them to react quickly to signals given out by other animals.

The Effect of Stimuli on the Behaviour of an Organism

Animals and plants react to stimuli (sing. stimulus) which may come from other living things or from the environment. A stimulus usually causes the organism which receives it to respond to it. Therefore the stimulus changes the behaviour of the organism in some way.

A rabbit eating grass in a field needs to be constantly alert and must be able to react quickly to stimuli such as movement, a sound or a strange smell in the air. The rabbit responds to these stimuli by quickly moving out of danger. This movement is the response to the stimulus and the rabbit's behaviour has changed from being still and eating to moving out of danger.

Some stimuli are only given out by animals and plants at certain times of the year.

Many animals mate in the Spring. The males of certain species change their behaviour in a way which will attract females, or vice versa. The behaviour of many species of birds can be used as a good example to illustrate this point. Many male birds start to sing in Springtime. Each species of bird has its own particular song to attract females of the same species.

Some male birds develop colourful plumage so that the females will be attracted by a visual stimulus as well as by sound. This is interesting because it shows us that a stimulus not only changes the behaviour of an organism but it can also change the way it grows and develops.

Most stimuli are precise and the behaviour of an organism in response to a stimulus is often immediate. We call this a reflex reaction. A bird will respond to the open mouth of its chick by dropping food into it. This reaction is so automatic that the bird will place the food into an open mouth of a fish at the surface of the water!

Humans also show automatic reactions. New born babies will hold onto something which is put into their hand, such as a finger. This is called the grip reflex. This reflex can also be seen in monkeys and apes - the young use it to hang on to their mothers.