264 ANIMAL LIFE 
insects, but with masses of pollen or pollen mixed with 
nectar. 
147. The vertebrates.—It is among the vertebrates, espe- 
cially in the higher groups, the birds and mammals, that 
we find the care of the young most perfectly undertaken 
and most widespread. 
Among the fishes, the lowest of the vertebrates, most 
species content themselves with the laying of many eggs in 
a situation best suited for their safe hatching. But some 
species show interesting domestic habits. The female cat- 
fish swims about with her brood, much as a hen moves 
about with her chickens. Some of the larger ocean cat- 
fish of the tropics receive the eggs or the young within the 
mouth for safety in time of danger. Certain sunfishes care 
for their young, keeping them together in still places in the 
brook. They also make some traces of a nest, which the 
male defends. The male salmon scoops out gravel to make 
a shallow nest, in which the female deposits her eggs. The 
male then covers the eggs. The males of the species of 
pipe-fish and sea-horses receive the eggs of the female into 
a groove or sac between the folds of skin on the lower part 
of the tail. Here they are kept until the little fishes are 
large enough to swim about for themselves. The brave 
little sticklebacks build tiny nests about an inch and a half 
or two inches in diameter, with a small opening at the top. 
The eggs are laid in this nest, and the young fish remain in 
it some time after hatching. The male parent jealously 
guards the nest, and fights bravely with would-be intruders. 
The batrachians and reptiles rarely show any care for 
their young. The eggs of most batrachians are laid in the 
water and left by the female. The males of the Surinam 
toad receive the eggs in pits of the spongy skin of the back, 
where they remain until the young hatch. The eggs of 
snakes are laid under logs or buried in the sand, and no 
further attention is given them by the parents. 
Among the birds, on the other hand, nest-building and 
