188 POUCHED MAMMALS 
jumping machine. The tail not only assists the animal in 
leaping, but it also serves as a balancing pole, and keeps its 
i“ p 
BRUSH-TAILED ROCK WALLABY (Petrogale penicillata). 
Length, head and body, 28 inches; tail, 24 inches. 
owner from losing his proper position when in mid-air. It 
is reasonably certain that a Kangaroo without a tail would 
when leaping frequently overbalance and turn somersaults. 
Kangaroos were once very abundant in Australia, but the 
