Both dogs and cats evolved as carnivores, but the cat is somewhat unique in that it is an obligate carnivore. That is, it requires certain nutrients that are available only from animal sources. The feline intestine is adapted for a high fat, high protein diet.
Some people tend to treat the cat like a small dog, but the cat has very specific nutritional requirements. This is because, unlike dogs, the cat is unable to synthesize certain essential nutrients from other food components and, therefore, requires these nutrients to be pre-formed in their diet.
Protein: Cats have the highest requirement for protein of all domesticated species. When cats were evolving, a high protein and fat diet was always available so cats never found it necessary to conserve proteins. Cats always "waste" some of the dietary protein by breaking it down for energy.
Taurine: Cats require taurine because they cannot convert other amino acids into taurine. Taurine is important to prevent visual, cardiac and reproductive problems and is found only in meat and fish.
Fats: Cats also require both linoleic and arachidonic acids to prevent skin and coat problems and poor reproduction. Arachidonic acid is found only in animal sources of fat.
Vitamins: Pre-formed vitamin A must also be present in the cat's diet. Dogs can break b-carotene into two molecules of vitamin A; cats cannot. Pre-formed vitamin A is also found only in animal tissues.
Cats are also somewhat peculiar in their eating behavior. Cats will tend to eat and drink limited quantities on numerous occasions, consuming up to 16 small meals during a 24-hour period when fed on an ad lib basis.
