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such as elephants and hippopotamus, jumping may be very difficult or
even impossible. Other animals may jump only very infrequently; still others
depend heavily on jumping and integrate it into other actions such as
running or climbing. Mountain goats often jump to traverse difficult terrain;
antelope and deer often leap as part of their running action, possibly to evade
predation.
In anticipation of leaping over an obstacle, a jumping horse plants both
its hind legs firmly on the ground together, squashing down slightly in
preparation for providing the necessary upward thrust. The head is held
upright during the first part of the jump, with the neck stretched forward
and downward in a counter-movement as the body rises. As the horse
leaves the ground, the hind legs are extended fully backward together while
the forelegs are bent and tucked tightly into the body to avoid contact
with the obstacle. As the horse is positioned over the obstacle, the hind
legs are bent and tucked in while the forelegs are extended fully forward in
anticipation of making contact with the ground. As the horse's body rotates
with the front end dropping the neck is pivoted and the head is once again
lifted.
FIG 4.32
Horse jumping
sequence.
Deer and antelope use a kind of bounding jump in their run actions. During
this action both front and hind legs become tucked into the body at the
same time and may be extended downward together, or at least much
closer together than when the animal is leaping over an object such as a
fence.
