The cat (or domestic cat, house cat); is a small carnivorous mammal that is often valued by humans for its companionship and its ability to hunt vermin. It has been associated with humans for at least 9,500 years. A skilled predator, the cat is known to hunt over 1,000 species for food. The cat is intelligent and can be trained to obey simple commands. Individual cats have also been known to learn to manipulate simple mechanisms. Cats use a variety of vocalizations and types of body language for communication, including mewing ("meow" or "miaow");, purring, hissing, growling, squeaking, chirping, clicking, and grunting.

Cats typically weigh between 2.5 and 7 kg (5.5–16 pounds);; however, some breeds, such as the Maine Coon, can exceed 11.3 kg (25 pounds);. Some have been known to reach up to 23 kg (50 pounds); due to overfeeding. Conversely, very small cats (less than 1.8 kg / 4.0 lb); have been reported.

Cats also possess rather loose skin; this enables them to turn and confront a predator or another cat in a fight, even when it has a grip on them. This is also an advantage for veterinary purposes, as it simplifies injections. In fact, the life of cats with kidney failure can sometimes be extended for years by the regular injection of large volumes of fluid subcutaneously, which serves as an alternative to dialysis.