736 MAMMALIA. 
between carnivores and herbivores, between birds of prey 
and small mammals; but combination for mutual defence 
often mitigates the intensity of the conflict. Teeth and 
claws, hoofs and horns, are the chief weapons, while the 
scales of pangolins, the bony shields of armadillos, the spines 
of hedgehogs and porcupines, and the thick hide of the 
rhinoceros, may be regarded as protective armature. In 
keeping their foothold some Mammals are helped by the 
harmony between their colouring and that of their surround- 
ings; thus the white Arctic fox and hare are inconspicuous 
on the snow, the striped tiger is hidden in the jungle, and 
many tawny animals harmonise with the sandy background 
of the desert. 
The majority of Mammals are gregarious; witness the 
herds of herbivores, the cities of the prairie-dogs, the packs 
of wolves, the schools of porpoises, the bands of monkeys. 
Combinations for attack and for defence are common; 
sentinels are posted and social conventions are respected ; 
such migrations as those of the lemming and reindeer are 
characteristically social. In the beaver village and, among 
monkeys there is combination in work, and their communal 
life seems prophetic of that sociality which is distinctively 
human. 
Among Birds, mates are won by beauty of song and 
plumage ; Mammals not less characteristically woo by force. 
Rival males fight with one another, and are usually larger 
and stronger than their mates. The antlers of male deer, 
the tusk of the male narwhal, the large canine teeth of boars, 
illustrate secondary sexual characters useful as weapons. 
But manes and beards, bright colours and odoriferous 
glands, are often more developed in the males than in the 
females, and may be of advantage in the rough mammalian 
courtship. At the breeding season a remarkable organic 
reaction often affects the animal: the timid hare becomes a 
fierce combatant, and love is often stronger than hunger. 
The courtship of Mammals is usually like a storm—violent 
but passing; for, after pairing, the males return to their 
ordinary life and the females become maternal. Some 
monkeys are faithfully monogamous; and exceptional pairs, 
such as beavers and some antelopes, remain constant year 
after year; but this is not the way of the majority. 
