98 
MAMMALIA. 
the trouble to fix up their nests at all. At such times they simply 
crawl into any convenient shelter, without gathering so much as a 
bunch of moss to soften their bed. Snow completes the covering, 
and as their breath condenses and freezes into it an icy wall begins 
to form, and increases in thickness and extent day by day till they are 
soon unable to escape, even if they would, and are obliged to wait 
in this icy cell till liberated by the sun in April or May. 
The diminutive size, premature appearance, and helpless condition 
of the young of this species at birth cannot fail to excite surprise. 
They are not six inches (i 52 mm) in length, weigh less than a 
pound (453.6 grams), and are not yet covered with hair. Their eyes 
do not open for more than a month. I know of no other mammal, 
except among the Marsupials, whose young are so disproportion- 
ately small, or are born in such an undeveloped condition. It is 
necessary for their preservation that the mother should cover them 
nearly the whole time for the first two months. 
Mr. Frank J. Thompson, Superintendent of the Zoological Garden 
at Cincinnati, has published a thoroughly trustworthy account of the 
early development of a litter of Black Bears, in confinement; and 
observations of this nature are so rare that I here reproduce the 
main part of his communication : 
“ About the middle of January last, the female Black Bear in the 
Society’s collection refused to come out of her den into the open pit 
and would not allow the male to approach her. She was immediately 
closed in and furnished with an abundance of hay, with which she 
busied herself in making a nice warm bed. At 4 p. m. on January 
26th, the young ones were born and I did not see them until the 
third day after, when I was surprised by the keeper informing me 
that she would allow him to enter the den. On going with him, he 
unlocked the door, fearlessly walked in, and quickly began feeding 
her with bits of bread, which he sliced from a loaf held in his hand. 
By holding the bread just over her head, he finally tempted her to 
sit up on her haunches, when I obtained a clear view of the two 
