THE LIFE OF MAMMALS 
it naturally took to killing them, and thus aroused a war of ex- 
termination. So well armed are its great jaws and so courageous 
is its fury that even a pack of dogs will refuse to attack an old 
‘““wolf” with his back to the wall. They rarely show them- 
selves by daylight, and then seem slow, dull-witted, and half 
blind, but make their forays at night, each hunting alone, and 
with no more voice than a low growl. A few have been caught 
alive and soon adapt themselves to captivity, so that all the 
larger zodlogical gardens now exhibit them and even cause 
them to breed. Mr. R. Gunn, who sent a female to the Lon- 
don ‘‘Zoo,” wrote of her as follows: — 
“The present one, in giving suck to its young, used to lie down like a dog, 
the skin of the pouch being thrown back so as to admit of the young ones 
getting easily at the teats. When alarmed, the young ones crawled in with 
their backs downwards, the mother assisting by lowering her hind quarters 
to facilitate them getting in, and by also placing her rump against the side 
of the cage to give the cubs a purchase with their hind legs against the cage, 
and thus push themselves in.” 
A word or two here about the pouch. In the kangaroos and their kin 
this organ is most highly developed and longest used by the young. As 
Relation the line is approached separating the diprotodonts from the 
ce zene e polyprotodonts, the opening of the pouch changes from front 
Develop- to rear, and when the smaller dasyures are reached it is seen 
ment. to be very restricted and to open by a slit straight downward; 
and the kittens make little use of it after once getting out. In the pouched 
mice, despite their name, it is so small as practically to be wanting; and in 
Antechinus and the ant-eater there is no pouch at all, the teats being pro- 
tected merely by the long hair among which the young cling until they 
mature. This deficient condition characterizes the opossums, with two 
specialized exceptions. These very exceptions, in the opinion of Dr. 
Lydekker, ‘‘demonstrate that this organ is primitively an essential char- 
acteristic of marsupials, and not one that has been specially developed to 
suit the exigencies of the various modes of life of the Australian members 
of the order. Consequently those forms, like the majority of the opossums 
and the banded ant-eaters, which have either no pouch or merely a rudi- 
ment thereof, may be safely assumed to have lost that organ through spe- 
cialization. The reason of the loss of such an organ, which appears so 
512 
