448 
UNGULATES. 
which appears specifically indistinguishable from the living kind was widely spread 
over Europe, extending from Italy in the south to England in the north. These 
fossil hippopotami were, however, of considerably larger dimensions than at least 
the average of the existing race. In England the range of the animal extended as 
far north as Yorkshire; and it is a remarkable circumstance that in several English 
localities remains of the hippopotamus are found lying side by side with those of 
the reindeer. It has been attempted to explain this association of such southern 
and northern types by assuming that in the Pleistocene period the summers were 
very hot and the winters very cold, and that during the summer the hippopotami 
wandered northwards into regions tenanted in winter by the reindeer. There are, 
however, difficulties in the way of accepting this explanation, not the least being 
the circumstance that the living African hippopotamus is not a migratory animal. 
We may, however, be pretty confident that wherever remains of hippopotami are 
found, there the rivers must have been free from ice throughout at least the greater 
part of the year. 
h The hippopotamus is more essentially an aquatic animal than any 
other Ungulate, the greater portion of its time being spent in the 
water, where its movements are far more rapid and natural than they are on land. 
As the carcase of a hippopotamus when freshly killed sinks rapidly to the bottom, 
the specific gravity of the animal when the lungs are inflated with air cannot be 
far, if at all, below that of water, and the animal is consequently enabled to stay 
without difficulty at the bottom of a river or lake, where it can run with ease and 
speed. Sir S. Baker states that, when undisturbed, the average duration of time 
during which a hippopotamus remains under water does not exceed five minutes; 
but in regions where these animals are much hunted the length of the immersion 
is often much greater, sometimes extending to as much as ten minutes. The same 
writer also mentions that when on the upper Nile in a steamer that was travelling 
about ten knots an hour, it was not till the engineer increased the pace by putting 
on full steam, they were able to overtake a hippopotamus swimming about a 
hundred yards in advance of the vessel. When a hippopotamus comes to the 
surface it generally spouts up a column of water by the violent blowing-out of air 
through the nostrils, accompanied by a loud snorting noise; but, as we shall again 
notice, these animals learn caution in these respects when much persecuted. A 
peculiarity of the hippopotamus is that when swimming in the water and about to 
dive, it gradually subsides by slowly sinking the hind-quarters and afterwards the 
rest of the body, instead of sinking down head-foremost. When on a high bank 
and suddenly frightened, it will not, however, hesitate to precipitate itself 
headlong into the water. 
As the giraffe may be regarded as the most characteristic and striking animal 
in an African desert-landscape, so the hippopotamus forms the most distinctive 
living feature in a river-scene; and nothing can be more impressive than to come 
suddenly upon a herd of these gigantic animals on the margin of some unfrequented 
lake or river. Such a scene is graphically described by Mr. Selous, who writes 
that on one occasion his companion and himself, after making their way through a 
thick bush-jungle, suddenly emerged upon a river-bank. “ Upon a spit of white 
sand which jutted into the pool from the opposite bank, stood, high and dry, a herd 
