Cats that inhabit woods tend to be darker than those on the plains, and are also more brilliantly marked. Cats are digitigrade, meaning they walk on their toes rather than on their entire foot, like a human or bear. Cats can also climb down a tree forwards and backwards, due to a very flexible ankle joint. Cats vertebrae are very flexible, and they are capable of contorting themselves into almost any position. This also minimizes damage caused from a fall to their limbs and internal organs.
Cats have a bony structure in their penis called a baculum.
They also have sharp backwards facing barbs on their penis as well. These are used to stimulate ovulation, as female cats are induced ovulators, meaning they will not ovulate before mating. This, coupled with the fact that more than one egg is released at a time and at different times, means that kittens or cubs in a litter can have different fathers. Cats communicate in a variety of ways, from scent to visual to vocal. Cats will regularly mark off their territory with urine.