Mammals are a group of vertebrates, which due to their high organization can adapt to life in a variety of environments. Live on land and under it in the open and in the densest forests and thickets, in salt water and fresh water, air, swamps and deserts, and mountains, well above the limit of vegetation. Compared to the animals closely related to the environment semi-aquatic mammals that live on land show a much larger variety of the body. Most mammals running around the herbivorous organisms, which are generally completely helpless in the event of an attack.