Nest build fresh nests daily out of leaves and other vegetation in which they sleep at night. They sometimes also build nests during the day for resting in. The smaller species of gorilla build their nests in trees, while the larger are confined to the ground. Nests of the western gorilla, the largest species, measure about in diameter. Some species of frog build nests ranging from simple to modest complexity. Many stream-dwelling frogs lay their eggs in a gelatinous mass which they attach to underwater vegetation. The jelly structure prevents the eggs from washing away. Fish engage in nest building activities
Mammal Mammal Mammals ( from Latin "mamma" "breast") are vertebrate animals constituting the class Mammalia, and characterized by the presence of mammary glands, which in females produce milk for feeding (nursing) their young; a neocortex (a region of the brain); hair; and three middle ear bones. These characteristics distinguish them from reptiles and birds, from which they diverged in the late Triassic. There are around 5,450 species of mammals. The largest orders are the rodents, bats and Soricomorpha (shrews and allies). The next three are the Primates (apes, monkeys, and allies), the Cetartiodactyla (whales and even-toed ungulates), and the Carnivora (cats,