ORDER VIII. _Pici._ Woodpeckers. Two toes point forward, two backward, and adaptation for climbing. Long, strong bill. ORDER IX. _Psittaci._ Parrots, hooked beak and fleshy tongue. ORDER X. _Coccyges._ Climbing birds, with powerful beak. Examples: kingfisher, toucan, and cuckoo. ORDER XI. _Macrochires._ Birds having long-pointed wings, without scales on metatarsus. Examples: swift, humming bird, and goatsucker. Mammals.--Dogs and cats, sheep and pigs, horses and cows, all of our domestic animals (and man himself) have characters of structure which cause them to be classed as mammals. They, like some other vertebrates, have lungs and warm blood. They also have a hairy covering and bear young developed to a form similar to their own,[28] and nurse them with milk secreted by glands known as the _mammary glands_; hence the term "mammal." Footnote 28: With the exception of the monotremes. [Illustration: The bison, an almost extinct mammal.] Adaptations in Mammalia.--Of the thirty-five hundred species, most inhabit continents; a few species are found on different islands, and some, as the whale, inhabit the ocean. They vary in size from the whale and the elephant to tiny shrew mice and moles. Adaptations to different habitat and methods of life abound; the seal and whale have the limbs modified into flippers, the sloth and squirrel have limbs peculiarly adapted to climbing, while the bats have the fore limbs modeled for flight. Lowest Mammals.--The lowest are the monotremes, animals which lay eggs like the birds, although they are provided with hairy covering like other mammals. Such are the Australian spiny anteater and the duck mole. All other mammals bring forth their young developed to a form similar to their own. The kangaroo and opossum, however, are provided with a pouch on the under side of the body in which the very immature, blind, and helpless young are nourished until they are able to care for themselves. These pouched animals are called _marsupials_. The other mammals may be briefly classified as follows:-- CLASSIFICATION OF HIGHER MAMMALS ORDER I. _Edentata._ Toothless or with very simple teeth. Examples: anteater, sloth, armadillo. ORDER II. _Rodentia._ Incisor teeth chisel-shaped, usually two above and two below. Examples: beaver, rat, porcupine, rabbit, squirrel. ORDER III. _Cetacea._ Adapted to marine life. Examples: whale, porpoise. ORDER IV. _Ungulata._ Hoofs, teeth adapted for grinding. Examples: (_a_) odd-toed, horse, rhinoceros, tapir; (_b_) even-toed, ox, pig, sheep, deer. ORDER V. _Carnivora._ Long canine teeth, sharp and long claws. Examples: dog, cat, lion, bear, seal, and sea lion. ORDER VI. _Insectivora._ Example: mole. ORDER VII. _Cheiroptera._ Fore limbs adapted to flight, teeth pointed. Example: bat. ORDER VIII. _Primates._ Erect or nearly so, fore appendage provided with hand. Examples: monkey, ape, man.