The Lee County journal. (Leesburg, Ga.) 1904-19??, 1908-01-24

Inc necessity OF auulIlOnal alu LOT Ine
purpose of tree-climbing They have
accordingly developed on the under
surface of the tail certain structures
which may be compared to the climb
ing irons used by workmen. These
take the form Of few transverse
rows OF large. triangular, horny scales,
with their points directed backward.
These scales, when pressed against
the bark of tree, must afford mate
rial aid in climbing. Another group
OF animals in which climbing irons"
have been developed is that Of the
scaly anteaters, or pangolins, Of India
and Asia-creatures which look more
like living fir-cones than mammals.
The scales-much larger than those
Of the scaly-tailed squirrels--coyer
both surfaces of the body, as we'll as
the head and limbs, so that it can
scarcely be supposed they have been
developed for climbing. Indeed, only
a few species climb, but these have
found the assistance afforded by the
scales on the upper side of value in
an ascent, and habitually make use Of
them as climbing irons.
Quite a different type of climbing,
or rather hanging, apparatus has been
developed in the sloths of tropical
America, which spend their time in
the tree tops, where they remain
suspended back downward by their
hook-like claws. These claws, which
may be three or two, have been modl-
fed from ordinary claws, and afford o
striking instance of adaptation to an
abnormal mode of life. The thumb Of
bats is likewise modified into hook
like claw-also used for suspending
purposes when the creatures hang
head upward. Generally, however,
bats suspend themselves head down
ward by the hind claws, grasping
power being retained. by the toes, so
that the modification has not been car
ried to the same extent as in sloths,
in which the claws act in mechani-
cal manner.
Certain bats appear to have found
their hook-like thumbs and hind feet
insufficient for suspension, and have
made use Of the sucker principle for
this purpose. This mode of suspen-
sion has been developed Independently
in two distinct bats, one a native Of
Brazil and the other OF Madagascar
In the Brazilian species the suckers
take the form of stalked disks attach
ed to the palms Of the thumbs and the
soles of the feet. The suckers of the
Malagasy species are horseshoe-like.
BY means of the suckers these bats
are able to ascend vertical surfaces
Very curious is it to note the similar
ity between the suckers of these bats
and those on the arms of cuttlefishes
The geckos which run up the walls
and over the ceilings of houses in
warm countries afford another In
stance of the sucker principle. Bats
are not the only mammals which
have ayailed themselves of the suck
err In the Malay islands and the
Philippines dwell large-eyed and slen-
der-limbed little lemur-like creatures
known as tarsiers, whose habits are
nocturnal. In these weird little ami
mails the tips of the toes are expfHded
into cushion-like disks, capable of act
ing like suckers, by means of which
they ascend such smooth surfaces as
the stems of bamboos.
Hoofed, or ungulate, mammals, such
as sheep, pigs, camels and elephants,
have given up using their fore-limbs
in a hand-like manner and employ
them solely for progression. Conse-
quently, tree climbing is out of their
line. III Africa and Syria there occur
however, certain representative Of
the order known as rock rabbits, or
hyrax, the Syrian species being the
one referred to in the Bible as the
coney (the old name Of the rabbit.
Certain African hyraxes have, how
ever, taken to tree climbing, and the
way they manage it is this: In each
foot the sole is somewhat cup-shaped,
and by the aid of muscular action,
the centre can be more elevated, so
that when the edges are applied to the
bark the foot acts like sucker.
This sucker-like action in the feet
Of the tree hyraxes is probably Of re-
cent origin, since it is certain that
these animals have taken to an arbo-
real life at a late stage in their ca
reer. Enlisting the services of the
tail to act as fifth hand in climbing
is, on the other hand, in all probable
ity feature of great antiquity, seeing
that it occurs IN the American opos-
sums, which are among the Oldest of
mammals. Doubtless, however, this
development of grasping power in the
tail has occurred independently in sew
eral groups.