Chap. XVIIL 
DEVELOPMENT OF HAIR. 
281 
duction. He gives, however, only a conjectural and 
unsatisfactory explanation of its use.^^ 
In most cases, when during the breeding-season the 
male alone emits a strong odour, this probably serves 
to excite or allure the female. We must not judge 
on this head by our own taste, for it is well known 
that rats are enticed by certain essential oils, and 
cats by valerian, substances which are far from agree- 
able to us ; and that dogs, though they will not eat 
carrion, sniff and roll in it. From the reasons given 
when discussing the voice of the stag, we may reject 
the idea that the odour serves to bring the females* 
from a distance to the males. Active and long-continued 
use cannot here have come into play, as in the case of 
the vocal organs. The odour emitted must be of con- 
siderable importance to the male, inasmuch as large 
and complex glands, furnished with muscles for evert- 
ing the sack, and for closing or opening the orifice,^ 
have in some cases been developed. The development 
of these organs is intelligible through sexual selection, 
if the more odoriferous males are the most successful in 
winning the females, and in leaving offspring to inherit 
their gradually-perfected glands and odours. 
Development of the Hair , — We have seen that male 
quadrupeds often have the hair on their necks and 
shoulders much more developed than in the females ; 
and many additional instances could be given. This 
sometimes serves as a defence to the male during his 
battles; but whether the hair in most cases has been 
specially developed for this purpose is very doubtful. 
We may feel almost certain that this is not the case. 
Pallas, ‘ Spicilegia Zoolog.’ fasc. xiii. 1799, p. 24 ; Desmoulins, 
‘ Diet. Class. d’Hist. Nat.’ tom. iii. p, 586. 
