The little dormouse has now awakened from his fitful sleep. When the
winds of March sweep away the lingering fogs of winter,--when the tender
buds are first seen on the trees, and the primrose first shows its head
in the green banks--before the swallow comes to our shores, or the rook
has finished her nest--the dormouse rouses up from the bed where he has
slept for several months. His sleep, however, is not constant through
the cold season, like that of some other animals; for he wakes, at
times, to eat of the store of nuts and beech-mast which he has provided
for his sustenance in the autumn. The marmot, a quadruped inhabiting
some mountainous parts of Europe, makes no provision of this kind in his
subterranean galleries. He sleeps completely.
M. Mangili, an Italian naturalist, made some curious experiments upon
the dormouse and other animals which sleep during the cold weather. He
kept the dormouse in a cupboard in his study. On the 24th December, when
the thermometer was about 40°, that is 8° above the freezing point, the
dormouse curled himself up amongst a heap of papers and went to sleep.
On the 27th December, when the thermometer was several degrees lower, M.
Mangili ascertained that the animal breathed, and suspended his
respiration at regular intervals;--that is, that after four minutes of
perfect repose, in which he appeared as if dead, he breathed about
twenty-four times in the space of a minute and a half, and that then his
breathing was again completely suspended, and again renewed. As the
thermometer became higher, that is, as the weather became less cold, the
intervals of repose were reduced to three minutes. On the contrary, when
the thermometer fell nearly to the freezing point, the intervals were
then six minutes. Within ten days from its beginning to sleep (the
weather then being very cold), the dormouse woke and ate a little. He
then went to sleep again; and continued to sleep for some days, and then
to awaken, throughout the winter; but as the season advanced, the
intervals of perfect repose, when no breathing could be perceived, were
much longer, sometimes more than twenty minutes. The effects of
confinement upon this individual animal caused him to sleep much longer
than in a state of nature.
When a dormouse is discovered asleep, in his natural retreat, he is cold
to the touch, his eyes are shut, and his respiration is slow and
interrupted, as just described. Torpid animals, in general, when thus
found, may be shaken, or rolled, or even struck, without a possibility
of arousing them. But as the fine weather advances, the heat of their
bodies increases, as it decreases at the approaches of winter; till at
length they shake off their drowsiness, and are again the busy and happy
inhabitants of the fields and gardens, active in the search of food to
gratify their appetite, which is now as keen as it was dull in the cold
months. These movements of course depend upon the states of the
atmosphere, and are different in individuals of the same species.