An introduction to the study of mammals living and extinctLydekker, Richard
Science
An introduction to the study of mammals living and extinct
Lydekker, Richard
Mammals
Manatees pass the whole of their life in the water, inhabiting bays,
lagoons, estuaries, and large rivers; but the open sea, so congenial
to the Cetacea, is quite unsuited to their peculiar mode of life. As a
general rule they prefer shallow water, in which, when not feeding, they
lie near the bottom, supporting themselves on the extremity of the tail,
or slowly moving about by the assistance of the fore limbs, the tips of
which are just allowed to touch the ground, and only raising the top of
the head above the surface for the purpose of breathing at intervals of
two or three minutes. In deeper water they often float, with the body
much arched, the rounded back close to the surface, and the head, limbs,
and tail hanging downwards. The air in the lungs obviously assists them
to maintain this position, acting in the same manner as that in the
air-sac of fishes. Their food consists exclusively of aquatic plants,
on which they browse beneath the water. They are extremely slow and
inactive in their movements, and perfectly harmless and inoffensive.
Frequent attempts have been made to keep specimens alive in captivity,
and sometimes with considerable success, one having lived in the Brighton
Aquarium for upwards of sixteen months. It was fed chiefly on lettuce
and endive, but would also eat leaves of the dandelion, sow-thistle,
cabbage, turnip, and carrot. From this and other captive specimens some
interesting observations upon the mode of life of the animal have been
made. One of these is the free use it makes of its fore limbs. From the
shoulder-joint, they can be moved in all directions, and the elbow and
wrist permit of free extension and flexion. In feeding these creatures
push the food towards their mouths by means of one of the hands, or both
used simultaneously, and any one who has seen these members thus employed
can readily believe the stories of their carrying their young about
under their arms. Still more interesting and quite unique among mammals
is the action of the peculiar lateral pads formed by the divided upper
lip, thus described by the late Professor Garrod: “These pads have the
power of transversely approaching towards and receding from one another
simultaneously (see Fig. 73, A and B). When the animal is on the point of
seizing (say) a leaf of lettuce, the pads are diverged transversely in
such a way as to make a median gap of considerable breadth. Directly the
leaf is within grasp the lip-pads are approximated, the leaf is firmly
seized between their contiguous bristly surfaces, and then drawn inwards
by a backward movement of the lower margin of the lip as a whole.” The
animal is thus enabled by the unaided means of the upper lip to introduce
food placed before it without the assistance of the comparatively
insignificant lower lip, the action greatly recalling to the observer
that of the mouth of the silkworm and other caterpillars, in which the
mandibles diverge and converge laterally during mastication. When out
Public-domain text, read in full here on John Shaqi.
Reviews
Reviews
No reviews yet
Be the first to share your thoughts on this work.
Elsewhere in the archive
Join the Discussion
Join the discussion
Sign in to leave a comment or review.
Sign InorCreate an account