Rodents.—Rabbits and hares, rats and mice, and squirrels are said to be rodents (Lat. rodo, I gnaw), as they not only agree in the gnawing habit, but also in other very important respects.
Mammals.—Rodents, and all other animals which suckle their young, are included by naturalists in the class Mammalia. These animals agree further in breathing air, in having warm blood, and in being more or less completely covered with hair.
Vertebrates.—Mammals, birds, reptiles, amphibians, and fishes are grouped together to form the sub-kingdom Vertebrata. They are given this name because they all possess a spinal, or vertebral, column (which usually consists largely of a chain of bones), running below the dorsal surface ([p. 217]) of the body, from neck to tail.
The position of the rabbit in the animal kingdom.—It is clear from the above that the rabbit is, in the first place, a vertebrate animal; it belongs, secondly, to the mammalian class of vertebrates, and thirdly, to the rodent-order of mammals.
EXERCISES ON CHAPTER XII.
1. In what respects does the hind-foot of a rabbit differ from the fore-foot? What is the use of the difference?
2. Describe the way in which a rabbit runs. What precautions does it take when feeding in an open place? (1901)
3. Make observations of the habits and external characters of hares, and compare them, point for point, with those of rabbits.
4. Describe the inside of a rabbit’s mouth, and explain the advantages of any peculiar features to be seen in it.
5. Mention the two chief constituents of a rabbit’s tooth. Describe by what means the edges of a rabbit’s incisor teeth are kept sharp.