ZOOLOGICAL 
SOCIETY BULLETIN 73 
WHITE OR SQUARE-LIPPED RHINOCEROS 
The broad, square mouth and especially the horny edge of the lower lip, facilitates the cropping of grass, its only food. 
the left, this ridge, usually covered by the bulky snout, may be distinctly seen. 
common black rhinoceros. 
In the picture at 
The head of this species is much longer than that of the 
From contact with vegetation near the ground the anterior horn is worn off in front, and its base squarish 
The variation in size and shape of horns is very extensive. 
menacing horns suggest painful possibilities, 
and they would be formidable weapons of 
ageression were it not that the peaceful grazing 
habits of their owner have relegated them to 
an eminently practical use. In these regions of 
high grass, except during a few months after 
the annual grass fires, progress through the 
tangled mass of vegetation demands _ intense 
muscular exertion. The fending action of the 
horns, carried close to the ground, clears the 
way for the short, pillar-like front legs and 
barrel-shaped body as the animal slowly p: 
across country, or grazes with constantly nod- 
ding head. Imagine nearly forty pounds of 
horns on top of a long, wedge-like nose, swung 
sses 
about with astonishing ease, while tearing 
through the jungle. Quite naturally — this 
abrading use accounts for their general smooth- 
To this incidental friction, and not to a 
supposed special grinding action against stones 
or the ground, nor to digging, must be ascribed 
the flattening in front and the wear directly 
above the base of the anterior horn, as well 
as the posterior edge and often spatulate form 
of the rear horn. 
ness. 
Biase The factors giving the long, 
nysica : : : : 
Rentines weighty head such remarkable 
facility of movement are the 
highly efficient ball and socket joint hinging the 
head to the neck and the enormous band of 
sinewy nuchal muscles extending from the rear 
of the skull to the high processes of the verte- 
bral column. A huge mass of muscles on either 
side of this “rubber band” are responsible for 
the distinctive hump in front of the shoulder. 
At every sway of the head they exert an enor- 
mous pull on the upper corners of the skull, 
which perhaps has brought about its curious 
V-shaped dorsal outline in the rear. 
There are always two horns, ex- 
cept in young calves, where the 
posterior one is merely a slight hump. Far 
from being set directly upon the skull they rest 
upon the heavy hide, which runs beneath them 
without interruption. After two days of decay 
they easily can be pulled off the skin, to which 
they are attached only by small fibres sunk into 
innumerable tiny pits, but if haste is necessary 
they can be severed at once with a knife. In 
adults there is a roughened, granular area upon 
the naso-frontal bones beneath each horn. The 
slightly thickened patch of skin between horn 
and bone certainly forms an ideal cushion to 
absorb the shock of heavy blows. No doubt 
this is also an important function of the hide, 
which in some places is about two inches thick. 
It is toughest on shoulder, belly, and other parts 
exposed to abrasion in passing through the 
jungle. 
Horns 
Under normal circumstances, the front horn is 
much the longer of the two. In contrast with 
the roundish of the horn in the black 
species, that of the white rhinoceros is rather 
square. Individual variation in size and form 
base 
