THE COPULATORY ATTITUDES 69 
more than one of a pair is likely to be killed 
in an attack. The male’s death is nothing to 
the species, for he probably has already ferti- 
lised the female, if not during the last copula- 
tion, at a former one; her death would be 
a great loss to the species, the loss of very 
valuable fertilised ova. 
The length of time taken by the copula- 
tory act varies with the species, and among 
mammals is longest in the predatory ones ; 
compare, in this respect, the Felide Canidee 
and Mustelide with the Suid, Cervide 
Equide or Muride and Leporide. 
Among birds, I am aware of only one ex- 
ception to the rule that the male mounts the 
hen—Swans (Cygnus olor), which copulate 
breast to breast, and so will apparently be 
equally liable to be killed if then attacked. 
It is noteworthy, that of all birds, Swans are 
probably the least liable to attack, because of 
their pugnacity and great strength. 
In the majority of insects, the copulatory 
period is often prolonged for many hours or 
even days; during this long period the pairs 
are in a helpless condition, able only to make 
feeble attempts to escape from danger. In 
many species, the male rests on top of the 
female, as it were guarding her and often 
