Other rodents commonly used are guinea pigs, hamsters, and gerbils. Included are mice, rats, gerbils, hamsters, lemmings, and voles. Examples of monogastric herbivores are horses, rabbits, gerbils, and hamsters. The least weasel feeds predominantly on mouse-like rodents, including mice, hamsters, gerbils and others. Primarily a carnivore, the jungle cat prefers small mammals such as gerbils, hares and rodents. This includes such animals as domesticated cats, dogs, mice, and gerbils. The rough-legged hawk will also supplement its diet with mice, rats, gerbils, pikas and insects. Many species of rats, mice, gerbils and bats are also found in the park. Other animals can be infected with this disease, including weasels, gerbils, and squirrels. Sick fat-tailed gerbils get lethargic and are not lively. Almost all pet gerbils today are descended from them. Mongolian gerbils are regarded as monogamous within science. Between 20 and 50% of all pet gerbils have the seizure disorder epilepsy. Fat-tailed gerbils weigh about 40 grams. Within a laboratory setting many gerbils tend to keep to themselves and refrain from copulation.