Chap. XV 11. Mammals— Greater Size of Male. 51 j 



possessors, for their development consumes much organised 

 matter. A single tusk of the Asiatic elephant — one of the 

 extinct woolly species— and of the African elephant, have been 

 known to weigh respectively 150, 160, and 180 pounds ; and 

 even greater weights have been given by some authors.'^ W,' th 

 deer, in which the horns are periodically renewed, the drain OD 

 the constitution must be greater ; the horns, for instance, of the 

 moose weigh from fifty to sixty pounds, and those of the 

 extinct Irish elk from sixty to seventy pounds — the skull of the 

 latter weighing on an average only five pounds and a quarter. 

 Although the horns are not periodically renewed in sheep, yet 

 their development, in the opinion of many agriculturists, entails 

 a sensible loss to the breeder. Stags, moreover, in escaping 

 from beasts of prey are loaded with an additional weight for the 

 race, and are greatly retarded in passing through a woody 

 country. The moose, for instance, with horns extending five 

 and a half feet from tip to tip, although so skilful in their use 

 that he will not touch or break a twig when walking quietly, 

 cannot act so dexterously whilst rushing away from a pack 

 of wolves. "During his progress he holds his nose up, so 

 " as to lay the horns horizontally back ; and in this attitude 

 " cannot see the ground distinctly."'* The tips of the horns of 

 the great Irish elk were actually eight feet apart! Whilst the 

 horns are covered with velvet, which lasts with the red-deer for 

 about twelve weeks, they are extremely sensitive to a blow ; so 

 that in Germany the stags at this time somewhat change their 

 habits, and avoiding dense forests, frequent young woods and 

 low thickets.'^ These facts remind us that male birds have 

 acquired ornamental plumes at the cost of retarded flight, and 

 other ornaments at the cost of some loss of power in their battles 

 with rival males. 



With mammals, when, as is often the case, the sexes differ in 

 size, the males are almost always larger and stronger. I am 

 informed by Mr. Gould, that this holds good in a marked 

 manner with the marsupials of Australia, the males of which 

 appear to continue growing until an unusually late age. But 

 the most extraordinary case is that of one of the seals (Onllor- 

 hinus ursinus), a full-grown female weighing less than one-sixth 

 of a full-grown male.'" Dr. Gill remarks that it is with the 



" Emerson Tennent, 'Ceylon, 143. See also Owen, ' British 



1859, vol. ii. p. 275; Owen, ' Bri- F)ssii llammals,' on the Irish elk, 



tish Fossil Mammals,' 1846, p. 245. pp. 447, 455. 



'* Richardson, * Fauna Bor. Ame- ^* ' Forest Creatures,' by C. Boner 



"icayka,'on the moa^e, Alces palmata^ 1861, p. 60. 



Dp. 236, 237 ; on the expanse of the '' See the very interesting papei 



norns, 'Land and Water," 1869, p. by Mr. .1. A. Allen in ' liuil. M\i» 



