LONELY AUSTRALIA: THE UNIQUE CONTINENT 



497 



the pigs, which are found native on all 

 other continents and on many islands, are 

 absent from Australia. 



The continent has so long been isolated 

 that the passage for animals from other 

 land-masses lias been closed for millions 

 of years. Species and genera have 

 evolved, and some even disappeared, in 

 other continents, while Australia remained 

 apart, and so it comes about that most of 

 the forms known in other lands are repre- 

 sented neither by living nor by fossil 

 species. The barrier of water which pro- 

 tects Australia from animal immigrants 

 from other countries was formed at the 

 beginning of the "Age of Mammals," 

 before the prominent elements in, the 

 world's fauna — cats, swine, horses, cattle, 

 sheep, elephants, camels, rats, rabbits, 

 bears, monkeys, etc. — had originated. 

 These, therefore, are not native to Aus- 

 tralia, which possessed mammals of only 

 the most primitive types. 



the: world's strangest animals 



The great animal groups — the lizards, 

 tortoises, snakes, birds, fishes, crabs, etc. — 

 which developed in geological periods be- 

 fore the land bridges to other countries 

 had been destroyed, are represented in 

 Australia, but they have evolved along 

 distinct lines, and most of the genera and 

 species are peculiar to the continent. 



The most primitive order of mammals, 

 the monotremes, are confined to Aus- 

 tralia. There is the platypus, a strange 

 beast which lays eggs like a turtle, but 

 suckles its young; has horny pads for 

 teeth and a bill like the duck ; its front 

 feet are webbed, and both back and front 

 feet have claws. Little wonder that he 

 has received many names, or that his 

 scientific designation is Ornithorhynchus 

 paradoxus (see page 5° 2 )- 



The spiny ant-eater is another strange 

 mammal. He looks and acts like a hedge- 

 hog, but he has a long beak and a longer 

 tongue, covered with a sticky substance, 

 with which he captures quantities of ants. 

 He not only burrows vertically into the 

 ground with great rapidity, but also 

 climbs with surprising agility. Like the 

 platypus, the spiny ant-eater lays eggs 

 which are hatched in a pouch and the 

 young reared on the mother's milk. 



The kangaroo is Australia's national 

 animal, and the group to which it belongs, 

 the marsupials, is typically Australian. 

 Marsupials — mammals whose young are 

 born very immature and then transferred 

 to a pouch and suckled — have been long 

 extinct in Europe and are represented in 

 America by unimportant survivors, like 

 the opossum. They belong to a past geo- 

 logical age, and have survived and flour- 

 ish in Australia only because the entrance 

 of carnivorous beasts has been barred by 

 the protecting zone of water. Primitive 

 forms have been allowed to persist, and 

 degenerate forms have not been elimi- 

 nated. 



COUSINS OF OUR 'POSSUM 



Like the eucalyptus of the plant world, 

 marsupials have dominated the animal 

 kingdom of Australia, and in their adjust- 

 ment to a varied environment have 

 evolved species very unlike in form and 

 manner of life. In size they range from 

 the giant kangaroo, the height of a man, 

 to creatures no larger than mice, and 

 extinct forms include diprotodon as large 

 as a rhinoceros, kangaroos more than 10 

 feet high, and a huge carnivorous beast as 

 big as a polar bear. 



Some marsupials live in trees ; others 

 roam the woods or desert ; still others 

 burrow in the ground. Some species eat 

 grass ; others live on leaves. One large 

 group is carnivorous, eating flesh or in- 

 sects ; another eats food of all kinds. 

 Some are nocturnal ; others seek their 

 food by day. 



AN ANIMAL WITH FIFTY-FOUR TFFTH 



The Tasmanian devil is a ferocious 

 beast ; other forms are harmless, and 

 some are affectionate pets. One species 

 is blind ; another has toes like the deer. 

 Some have few teeth, but the striped ant- 

 eater has fifty-four, the greatest number 

 in any living land mammal. 



The great diversity of species is re- 

 flected by the popular names — tiger, 

 native cat, weasel, mole, rat, mouse, wolf, 

 bear, flying squirrel, opossum, ant-eater, 

 in addition to the terms kangaroo, wal- 

 laby, wombat, bandicoot, obtained from 

 the aborigines ; but all are marsupials. 



The kangaroos and the closely related 



