HUMAN AND OTHER SOCIETIES 127 
ing the less powerful, are sometimes satisfied 
by their banishment; the females may assist 
after a battle has declared the victors. The 
expelled males, without the protection of the 
“herd, probably quickly fall victims to preda- 
tory animals. 
3. By the destruction of males by females : 
this is not unknown. 
4. By enemies more frequently destroying 
males than females because of their possessing 
“attracting” characters. When a herd is 
attacked the males, because they possess com- 
bative and sacrificing instincts, usually protect 
the young and the females, and must often 
thus themselves be destroyed. 
If males and females were alike both in 
characters and instincts, as many females 
would be killed as males. 
By these methods, Natural Selection within 
the herd is controlled. The adult male pos- 
sesses special secondary sexual characters 
for purposes of offence and defence; the 
young males are like the females and do not 
present these characters, these offensive and 
defensive instincts, until sexually mature— 
this because young males are more valuable 
than old ones. 
The attracting colour of male birds, which 
