Like any other animal, human beings have developed certain physical and behavioural traits. Some of these traits, such as a new born baby attempting to suckle the breast, are rooted in millions of years of past experience and can be thought of as instinctive. We can observe such traits in a dog as the behaviour of cocking the leg in male dogs. We can see some of our own traits in such things as the human desire to elect leaders. Many of these habits are psycho-biological or social. In our dreams we represent these drives or habits in the form of various animals. Our restrained sex drive or aggression may be shown in our dream as a dog on a lead. The power of drives such as the urge to parenthood via sex might be shown as a horse which we are trying to control. More than anything else though, our dream animal represents our powerful feeling reactions to situations - reactions developed through centuries of human experience in frequently terrible situations. This aspect of ourselves is rooted in the older portions of the brain.

Because dreams exhibit a powerfully precise way of using symbols, there is a difference in meaning between the wild animals and the domesticated animals we dream of. In general the domesticated animal such as a cat or horse represent urges we have more conscious control over and are therefore less threatening to our conscious desire to be in charge. The wild animals in our dreams often pose a much greater threat to our ego, but nevertheless offer rich rewards if we can develop a working relationship with them. After all they are aspects of ourselves, so the relationship can release more of our usable potential.
                *************************
Example: I am sitting in the hotel staff room eating lunch at a large dining table. One by one I am joined by perhaps a dozen women. The atmosphere is pleasant, easy and light hearted. I enjoy the feeling of being the only male among a dozen attractive women. Then I notice a strange thing. One by one all the girls around me turn into cats, but carry on laughing and talking as if nothing is happening. I find this interesting and not alarming. I am aware each girl turns into the sort of cat that is right for her - a vivacious redhead becomes a purring orange tabby; an aloof, slightly superior lady becomes a Siamese; the only ex-girlfriend of mine present becomes a black witches familiar.

I remember turning to my left and asking: "Tell me Rebecca, how did you do this?" The Rebecca cat giggles with a human voice and says: "He doesn't have a clue, does he?" As I look at the Rebecca cat I realise she still has her human eyes. This I realise is true of all the cats, they have human eyes in feline faces. As I realise this one says: "I think he's beginning to understand now" and laughs. Paul C. Teletext.
                *****************************
 
This graphic dream so well illustrates how we each have our human personality within our animal drives and urges.

The animal in our dreams has commonly been seen only as the sex drive. A careful examination of animal dreams shows this to be untrue. The animal represents all our biological needs and responses which include: Survival; hunger; reproduction; parental urges; need for exercise and rest; social drives; fear reactions; anger; urge to provide for young and mate; home/nest building; territory protection, social hierarchy, etc.
If these aspects in an individual are damaged or traumatised, the person might become a parent who has lost the natural bonding and care for their child; an individual who has no sense of social status or responsibility; criminally violent; someone with disturbed and misplaced sexuality.

Dominating or attempting to kill out the animal in us can cause tension, depression and illness. The escape into dry intellectualism is a cause of internal conflict. Complete permissiveness is no answer either. Our higher brain functions need expression also. So one of the challenges of maturing is how to meet and relate to our 'animals', and perhaps bring them into expression in a satisfying way. Such drives are fundamentally a push toward LIFE. Our dreams are selective in what animal is used to portray our situation. For instance a dog or horse are a creatures that have been socialised for thousands of years, whereas a dinosaur has no history of socialisation. These different animals can therefore be used to represent the socialised or untrained elements of ourselves.

It must be remembered that where sex or sexuality is mentioned, I am not simply referring to the sex act. I mean sexuality in its overall aspect, which includes the urge toward parenthood, and the love and caring connected with it. Brain damage or certain drugs or chemicals can diminish the 'human'  levels of function and only the animal and lizard levels express. Below are listed some common ways animals are used in our dreams..

Animal Situations
Neglect, mutilation or killing our 'animal': A common theme. In the example below, Lynda's feelings show how she senses what she is doing to her inner nature, but she dismisses this by convincing herself such feelings are not 'true'. We have a responsibility to care for our animal drives, to see our sexual, nutritional and body needs are met..
                *******************************
 Example: "I am given an animal to look after, usually somebody's pet while they are away on holiday. I then completely forget the animal, go away and when I return the animal is either dead or very dried up or has been got at by another animal and is in the throws of dying. When I wake from the dream I feel most dreadful and it is only when I am fully awake and realise it is not true do I feel better." Lynda E.
                *****************************************
Eating the animal: Integrating our natural wisdom and energy.  Hiding from or trapped by an animal: see the wolf entry. Animal with its young: Parental feelings; one's basic childhood needs. Baby animal: Oneself when young; baby feelings; desire for babies. See example in eating. Talking, shining, holy or wise animals: Important intuitive information; a meeting with the gathered wisdom we have unconsciously. This is one of the sources of religious inspiration, and many older cultures represent their origin of great learning or holiness as animals or animal headed beings. See: ape below; birds; creatures; pets; reptiles and snakes; the unconscious.

APE - Impulsive unreasoned urges such as self centred grabbing of food or sexual expression without concern for the other person; instinctive or intuitive wisdom about relationships, social interactions and life; folly or foolishness or feeling an idiot..
Can represent a world of experience human beings have lost and feel sorrow at its absence. In developing self consciousness, with its labyrinth of ideas and decisions, humans lost a sense of oneness with life around them. Animals have enormous remembered wisdom; remembered through instincts and complex social codes. Without it humans can feel alone in the world, a meaningless existence in the midst of uncaring circumstance. They are confronted by choices which, because they have lost an awareness of their instinctive wisdom, they often feel inadequately equipped to deal with.
This wisdom is still accessible to humans who know how to listen to the unconscious, and thus discover the enormous wealth of information they have about such things as social behaviour and body language.  The ape can depict this wisdom, especially if it is white haired. Or it might show the personal folly of trying to let instincts dominate us now we have self awareness. Idioms: He is just aping..

~by Tony Crisp, extracted from his dream dictionary, which covers all aspects of dreams and dreaming
http://dreamhawk.com/dream-dictionary/animals/