Kittens Eat... and Eat... and Eat Growing up is a very energetic business. A young kitten needs up to four times as many calories per pound of body weight as an adult cat. On the other hand, the kitten's stomach is much smaller than that of a grown-up cat -- at first not much larger than a human thumbnail. A kitten's food must be especially rich in calories and nutrients.
Amniotes are classified within the following taxonomic hierarchy: Animals Chordates Vertebrates Tetrapods. Amniotes are divided into the following taxonomic groups: 1  Birds (Aves) - There are about 10,000 species of birds alive today.
The non-mammalian members are described as mammal-like reptiles in classical systematics; they can also be called stem mammals or proto-mammals. Synapsids evolved from basal amniotes and are one of the two major groups of the later amniotes; the other is the sauropsids, a group that includes modern reptiles and birds. The distinctive temporal fenestra developed in the ancestral synapsid about 312 million years ago, during the Late Carboniferous period. Synapsids were the largest terrestrial vertebrates in the Permian period, 299 to 251 million years ago, although some of the larger pareiasaurs at the end of Permian could match them in size.