86 ANIMAL INTELLIGENCE 
arrival has been a frequent subject of regret by me, as I 
hoped to be able not only to continue the observations, 
but to make them comparative, as it was my intention 
to keep both under the same conditions—in fact, in the 
same cage. But the curious part remains to be told. 
Though I kept the remaining Woodchuck under exactly 
the same conditions as the animal I had had so long, he 
did not hibernate for an hour the whole winter, though 
he drowsed and slept enough. 
It has been generally considered that the hibernating 
conditions of animals was dependent above all else on 
the temperature of the surrounding atmosphere. My 
experiments in bats seemed to warrant this conclusion, 
for whenever the temperature reached the neighbour- 
hood of 45° F. to 40° F., the other conditions being 
favourable, my specimens began to hibernate. It was 
also true that my Woodchuck was in the deepest sleep 
during mid-winter when the cold is greatest. Whether 
a bat could be put into a state of torpor during summer 
by exposing it to a lowered temperature, I do not know. 
However, Marshall Hall maintained that the diurnal 
sleep of the bat (“diurnation”) was exactly the same 
phenomenon as the winter sleep. The same writer 
maintained that hibernating bats always awoke when 
the temperature fell below freezing point, and his 
observations showed that the temperature of the 
animals was always a few degrees above that of the 
surrounding atmosphere. Probably Hall is correct in 
the main, for my bats, when the temperature sank 
during the night much below freezing, were always 
found dead in the morning. Whether they awoke first, 
or simply passed from torpor to death, I do not know. 
However, for the Marmot, I can assert positively that 
this rule does not hold, for frequently the water was 
found frozen in the apartment in which the animal was 
kept, yet he was undisturbed. Nevertheless, I came to 
