The Gait of Land Animals 2 
smaller mammals. A few words must, however, be devoted 
to the hare and rabbit, which (and more especially the 
former) are characterised by the great relative length of 
the hind as compared with the fore-limbs. In consequence 
of this, these animals run much better uphill than down- 
hill. When at speed, they apparently gallop, but when 
going slowly they often move thew fore-limbs two or 
three times to one motion of the hind pair; consequently 
they may be said to walk with the former and hop with 
the latter (Fig. 19). 
From all the more typical hoofed mammals the elephant differs very markedly in 
the structure of its limbs, the component bones of which are set vertically one above 
the other without the slightest angulation. Consequently these animals are totally 
unable to jump, their progress being stopped by a six or seven-foot ditch which cannot 
be taken in thei stride. As regards the gait of elephants, I may quote from Mr. 
G. P. Sanderson, formerly superintendent of keddas im India, who writes that “the 
only pace of the elephant is the walk, capable of beimg increased to 
Abe a fast shuffle of about fifteen miles an hour for very short distances. 
Ce yy Wy... y It can neither trot, canter, or gallop. It does not move with the legs 
Akio 4/4 on the same side together, but nearly so” (Hig. 1). 
A Noh A certain number of mammals have forsaken the ordimary mode of 
Fig. 19. quadrupedal progression, and have taken to hop on their hind-legs, which 
for this purpose have been greatly elongated at the expense of the 
front pair. Among such mammals are the kangaroos (Fig. 20), wallabies, rat-kangaroos, 
and jerboa-rats (Conilwrus) of Australia; the jerboas of the Old World, the jumping mice 
of North America and Hastern Siberia, the American kangaroo-rats, and the jumping hare 
and elephant-shrews of Africa. The majority of these animals have evidently acquired 
their leaping powers quite independently of one another; and it is not a little remarkable 
that, with the exception of man and a few monkeys and lemurs which habitually assume 
the upright posture, no mammal in which the hind-limbs are alone used in progression 
has taken to walking or running, hopping being the invariable mode of advance. Neither 
has any mammal in which all four feet are habitually used taken to hopping. 
On the other hand, in birds there are a large number of species—mostly, by the 
way, of small bodily size—which hop (Vig. 21); while there are many others, notably 
the game-birds and the ostriches and their allies (Fig. 22), which run. There is also a 
lizard—the frilled lizard of Australia—which habitually assumes the erect posture, and 
walks and runs with great speed on its hind-limbs alone (Fig. 23). Doubtless some of 
the great extinct dinosaurian reptiles (such as our own iguanodon) which were bipedal 
likewise walked and ran, for it is practi- 
cally certain that they did not hop. In 
any case we have here again an instance 
where the upright posture has been inde- 
pendently acquired in two distinct groups, 
for no naturalist to whose opinion we should 
care to assign any weight would dream of 
suggesting that frilled lizards are the direct 
descendants of iguanodons. So far as I 
am aware there are no lizards that hop on 
their hind-legs in kangaroo fashion. 
As ostriches and frilled lizards exhibit 
a type of progression unknown among 
