260 SEXUAL SELECTION: MAMMALS. PakT II' 
With quadrupeds, when, as is often the case, the 
sexes differ in size, the males are, I believe, alwa) rS 
larger and stronger. This holds good in a marked 
manner, as I am informed by Mr. Gould, with the mai" 
supials of Australia, the males of which appear 
continue growing until an unusually late age. B 1 '* 
the most extraordinary case is that of one of fb® 
seals (Callorliinus ursinus), a full-grown female weigh' 
ing less than one-sixth of a full-grown male . 32 'U 1 ® 
greater strength of the male is invariably displayed’ 
as Hunter long ago remarked , 33 in those parts of tb e 
body which are brought into action in fighting with 
rival males, — for instance, in the massive neck of tb 0 
bull. Male quadrupeds are also more courageous t lJI< 
pugnacious than the females. There can be little 
doubt that these characters have been gained, parti)' 
through sexual selection, owing to a long series of xl °' 
tories by the stronger and more courageous males o? e 
the weaker, and partly through the inherited effects 0 
use. It is probable that the successive variations 
strength, size, and courage, whether due to so-call ® 1 
spontaneous variability or to the effects of use, bv tb® 
accumulation of which male quadrupeds have acqud'f 
these characteristic qualities, occurred rather late 
life, and were consequently to a large extent limit 0 
in their transmission to the same sex. 
Under this point of view I was anxious to obtc’ 1 ’ 
information in regard to the Scotch deer-hound, tb® 
sexes ot which differ more in size than those of aD ' 
other breed (though blood-hounds differ consul 01 
ably), or than in any wild canine species known to IlU 
32 See the very interesting paper by Mr. J. A. Allen in ‘ Bulb ^ 
Comp. Zoolog. of Cambridge; United States,' vol. ii. No. 1, p. 82. 1 
weights were ascertained by a careful observer, Capt. Bryant. 
33 1 Animal Economy, p. 45. 
