12 MAMMALS OF THE PACIFIC WOELD 



fish mixed with mud. Long burrows are made in the banks of 

 rivers, usually with two entrances — one of them below water. The 

 nest, made of grass, leaves, rootlets, and reeds, is placed in an 

 enlarged chamber at the inner end of the burrow. Usually two 

 or three eggs are laid, which are about seven-tenths of an inch 

 in length and only slightly less in diameter. The eggs have 

 horny white shells and become stuck together by means of a 

 sticky substance with which they are coated. It is estimated 

 that they hatch through the warmth of the mother's body in 

 about two weeks. The newly hatched young have not developed 

 the "duckbill" but have a hard, sharp process or "caruncle" on 

 the muzzle. They are said not to nurse for nearly a week. After 

 that the mother secretes milk through two milk patches (not 

 nipples), wetting the hairs thereon, which the young suck. 

 Scratching with their caruncles by the young is thought to start 

 the mother's milk flowing. 



Recently important new facts concerning the life habits of 

 the platypus have come to hand.^ These relate to a mother and 

 a young one bred at Badger Creek Sanctuary, Healesville, 

 Victoria, Australia. In the non-breeding season the platypus 

 spends a very large part of the twenty-four-hour day seeking 

 food at the bottom of its swimming tank. It eats enormous 

 amounts of animal food, the quantity of which probably rises 

 to a peak when it is nursing its young. At that time, in the 

 Sanctuary, a single night's food (which incidentally cost about 

 five dollars per day) comprised four hundred large earthworms, 

 three hundred and thirty-eight beetle grubs, and thirty-eight 

 small crayfish. The total weight of that food was one and three- 

 fourths pounds. Since the maximum live weight of the animal 

 was only two pounds, digestion must have taken place almost 

 concurrently with feeding. Maintenance of extreme activity — 

 swimming, digging, and giving of milk to the young platypus — 

 requires relatively very large amounts of that easily assimilable 

 vital fuel. 



^ Fleay, D., 1944, Animal Kingdom, New York, 47, pp. 61-69. 



