There are three main types of animals living on the Earth, carnivores, like felines and canines, herbivores like deer and bovines and omnivores like pigs and bears. They have evolved physically to eat specific foods. Each group has adapted the formation of the head, body, and digestive tract to accommodate for their eating habits. Because of their physical adaptions, dogs and cats are carnivores.
A carnivore is an animal that eats the flesh of other animals, usually grazing mammals, but they do eat other carnivores. In the wild they hunt down their prey. The kill is quick and the first thing they do is open the stomach and eat the digested vegetation.
From end to end carnivores have adapted physically to eating meat. Their eyes are set forward to focus on prey directly in front of them. Their muzzles are long with short pointed incisors to grasps while their long canine teeth penetrate and kill their prey. The sharp jagged molars are for ripping flesh and grinding bone. They have no digestive enzymes in their saliva because they do not need to breakdown carbohydrates. They just rip off a piece of meat from the carcass and swallow. They have extremely big stomachs to accommodate large quantities of food because they may not eat for days in the wild. Their small intestines excrete a strong acid to digest the flesh and their colon is short, about the same size as the small intestine since there is little water and salt in their food to absorb. Basically carnivores have a less primitive digestive tract than any other animal. Their bodies are very muscular with short legs and long tails which enables them to take down their prey.
Milwaukeeans can find out more about carnivores at the Milwaukee County Zoo.