There are many polysaccharides in animals, but I'm guessing you are looking for the answer of glycogen.
Polysaccharides are long chains of monosaccharides, or simple sugars. Through hydrolysis (losing a water molecule) they make very long chains called polysaccharides. Starch and cellulose are types of polysaccharides.
Starches are generally used as a long term source of energy and cellulose is a type of structural polysaccharide. Structural polysaccharides are most often found in the cell walls of plants to provide support and protection. Chitin is another type of structural polysaccharide that makes up the exoskeleton of insects.
The polysaccharide glycogen is produced and stored in the liver in animals. It is a stored form of energy.