288 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1949 
they learn to be alert, to beware of danger, to be on the watch for 
prey and how to catch it, and what to avoid. 
Mother deer (Odocoileus), antelope (Antilocapra), and moose (Alces) 
hide their newly born young and leave them hidden for some days. 
The baby antelopes may be left in plain sight on a grass-clad or very 
sparsely vegetated plain. Baby deer are hidden in the grass or sparse 
shrubbery, and baby moose may be hidden in such places or in slightly 
more dense vegetation. The mother then goes her way to get her 
food and rest, and returns to the little one only to nurse it at intervals 
of several hours. Thus the young are not exposed to the hazards of 
following the mother for the first few days until they have gained 
strength and are able to travel with such speed and endurance that 
they stand a good chance of survival by escaping with her. The mother 
cottontail rabbit (Sylvilagus) scratches out or selects a slight depression 
in the soil and lines it with fur that she plucks from the underside of 
her body. The depression is too small for her to be in it with the 
babies, but she crouches over it, and when the little ones nurse, they 
reach upward or climb up through the soft downy nest to reach her 
nipples. The cottontail nurses her little ones only at rather long in- 
tervals—apparently not at all during the daytime—and as long as 30 
hours are known to elapse between feedings in some instances. When 
danger threatens she dashes away and the enemy usually follows her. 
Mother sea otters (Enhydra), which spend a great deal of time in 
the ocean, lie on their backs much of the time and the babies rest on 
the mother’s ventral surface. When she dives for food she leaves the 
little one floating on the surface while she goes to the bottom and 
picks up sea urchins and other food which she brings to the surface 
and eats while lying on her back. 
A mother flying squirrel that raised her family in my home, has 
given me many glimpses of how she cares for her babies. Flying 
squirrels are, of course, strictly nocturnal and there would be many 
hazards for them in the daytime; therefore I was not surprised to find 
that ‘‘Mother Glaucky” carries her babies back into the nest when 
she finds that they have strayed out during the daytime. Perhaps 
she and the tree squirrels teach their babies by demonstration and by 
voice, but I have not been able to detect much evidence of this. The 
young play among themselves about the nest, gradually gaining 
strength and agility and venturing farther from the nest. The 
length of time that baby flying squirrels and baby tree squirrels are 
weak and uncertain in their movements and are dependent on the 
mother is much greater than is generally supposed. Baby flying 
squirrels do not venture out of the nest until they are about 60 days 
of age and then only to explore in the immediate vicinity of the nest. 
By the seventieth day they are venturing somewhat farther, but their 
muscles are still soft and they have not gained agility or confidence. 
