THE CONQUEST OF THE DRY LAND 215 
and at this stage they are terribly destructive, 
for they kill anything and everything that 
they find, whether they need food or not, and 
this is apparently done to excite the cubs so 
that they may become mighty hunters in their 
turn. The cubs remain with their parents till 
their third year, when they leave the den, but 
they do not reach their full growth and 
strength till they are about eight years old. 
When parental care grew strong it became 
unnecessary to have the multitude of offspring 
produced, for instance, by fishes, which may 
liberate millions of eggs. For the growth of 
parental care secured the continuance of the 
race with comparatively few offspring. But 
as the number of children decreased it became 
possible for the mother to know them all, to 
see more of them, and to have them longer 
with her, and all this meant more love. And 
more love meant more care. So things work 
round in a beautiful circle. 
Perhaps this argument may seem very diffi- 
cult, but it is very important. Let us think it 
over again. When it became possible for ani- 
mals to take great care of their children, it 
also became possible to have quite small fami- 
lies without there being any risk of the race 
