What is the stored carbohydrates in animals?

Glycogen is a long, very "branchy" chain of glucose molecules stored primarily in the liver and muscle tissue.

After eating, the liver converts much of the carbohydrate content of a meal into glycogen which keeps blood glucose levels at a relatively constant level (even if the meal is very high in sugar and other carboydrates). After the meal has been thoroughly digested and blood glucose levels begin to fall, the liver begins breaking down its glycogen stores to blood glucose levels so that other organs can continue to function normally.

Glycogen in muscles acts primarily as a "fast-acting" energy reserve for the muscles during strenuous exercise, and the glycogen in muscles cannot be used by any other parts of the body as muscle cells lack the enzyme that allows glucose to pass from the cells into the blood stream.

Adipose tissue (fat) is the main form of stored energy in animals, being much more compact than glycogen. However, it is a lipid, not a carbohydrate.