78 WILD NEIGHBORS CHAP 
it exists perfectly in the quaint little sea-horse 
(Hippocampus), which is a poor swimmer, and rests 
PREHENSILE TAIL OF THE 
SEA-HORSE, 
wrens (Certhiadz), and swifts. 
by hooking its tail 
around a bit of sea- 
weed or coral, or 
through a hole in a 
broken shell, thus an- 
choring itself securely. 
A service of the 
same nature is per- 
formed by the tail of 
many birds that are 
accustomed to climb 
about the trunks of 
trees, and cling to 
upright rocks, etc., in- 
stead of walking on 
the ground or perch- 
ing upon the branches. 
Familiar examples are 
the woodpeckers, nut- 
hatches, creeping- 
Whenever these 
birds rest a moment they press the tail hard against 
the bark or other surface to which they cling with 
muscular toes, and lean upon it. 
Such a leverage 
is very important to enable the woodpeckers and nut- 
hatches to deliver their sturdy and repeated blows ; 
and without such a support the swift could hardly 
hold itself, as it does for long periods, at rest 
