No fact comes to mind which is not more impressed upon us by the valuable
aid of comparisons, and Nature is ever offering antitheses. At this season
we are generally given a brief glimpse--the last for the year--of two
creatures, one a mammal, the other a bird, which are as unlike in their
activities as any two living creatures could well be.
What a type of lazy contentment is the woodchuck, as throughout the hot
summer days he lies on his warm earthen hillock at the entrance of his
burrow. His fat body seems almost to flow down the slope, and when he
waddles around for a nibble of clover it is with such an effort that we
feel sure he would prefer a comfortable slow starvation, were it not for
the unpleasant feelings involved in such a proceeding.
As far as I know there are but two things which, can rouse a woodchuck to
strenuous activity; when a dog is in pursuit he can make his stumpy feet
fairly twinkle as he flies for his burrow, and when a fox or a man is
digging him out, he can literally worm his way through the ground,
frequently escaping by means of his wonderful digging power. But when
September or October days bring the first chill, he gives one last yawn
upon the world and stows himself away at the farthest end of his tunnel,
there to sleep away the winter. Little more does he know of the snows and
blizzards than the bird which has flown to the tropics. Even storing up
fruits or roots is too great an effort for the indolent woodchuck, and in
his hibernation stupor he draws only upon the fat which his lethargic
summer life has accumulated within his skin.
As we might expect from a liver of such a slothful life, the family traits
of the woodchuck are far from admirable and there is said to be little
affection shown by the mother woodchuck toward her young. The poor little
fellows are pushed out of the burrow and driven away to shift for
themselves as soon as possible. Many of them must come to grief from hawks
and foxes. Closely related to the squirrels, these large marmots (for they
are first cousins to the prairie dogs) are as unlike them in activity as
they are in choice of a haunt.
What a contrast to all this is the trim feathered form which we may see on
the mill pond some clear morning. Alert and wary, the grebe paddles slowly
along, watchful of every movement. If we approach too closely, it may
settle little by little, like a submarine opening its water compartments,
until nothing is visible except the head with its sharp beak. Another step
and the bird has vanished, swallowed up by the lake, and the chances are a
hundred to one against our discovering the motionless neck and the tiny
eye which rises again among the water weeds.
This little grebe comes of a splendid line of ancestors, some of which
were even more specialised for an aquatic life. These paid the price of
existence along lines too narrow and vanished from the earth. The grebe,
however, has so far stuck to a life which bids fair to allow his race
safety for many generations, but he is perilously near the limit. Every
fall he migrates far southward, leaving his northern lakes, but if the
water upon which he floats should suddenly dry up, he would be almost as
helpless as the gasping fish; for his wings are too weak to lift him from
the ground. He must needs have a long take-off, a flying start, aided by
vigorous paddling along the surface of the water, before he can rise into
the air.
Millions of years ago there lived birds built on the general grebe plan
and who doubtless were derived from the same original stock, but which
lived in the great seas of that time. Far from being able to migrate,
every external trace of wing was gone and these great creatures, almost as
large as a man and with sharp teeth in their beaks, must have hitched
themselves like seals along the edge of the beach, and perhaps laid their
eggs on the pebbles as do the terns to-day.
The grebe, denied the power to rise easily and even, to ran about on land
without considerable effort, is, however, splendidly adapted to its water
life, and the rapidity of its motions places it near the head of the
higher active creatures,--with the woodchuck near the opposite extreme.