MAMMALS— GREATER SIZE OF MALE. 511 



skillful 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 atti- 

 "tude 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 ac- 

 quired 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 in- 

 formed 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 ex- 

 traordinary case is that of one of the seals (Callorhinus ursinus), 

 a full-grown female weighing less than one-sixth of a full-grown 

 male.^" Dr. Gill remarks that it is with the polygamous seals, the 

 males of which are well known to fight savagely together, that 

 the sexes differ much in size; the monogamous species differing 

 but little. Whales also afford evidence of the relation existing 

 between the pugnacity of the males and their large size compared 

 with that of the female; the males of the right- whales do not 

 fight together, and they are not larger, but rather smaller, than 

 their females; on the other hand, male sperm-whales fight much 

 together, and their bodies are "often found scarred with the im- 

 "print of their rival's teeth," and they are double the size of the 

 females. The greater strength of the male, as Hunter long ago 

 remarked,^' is invariably displayed in those parts of the body 

 which are brought into action in fighting with rival males — for 

 instance, in the massive neck of the bull. Male quadrupeds are 



5* Richardson, 'Fauna Bor. Americana,' on the moose. Aloes pal- 

 mata, pp. 236, 237; on the expanse of the horns, 'Land and Water,' 

 1SC9, p. 143. See, also, Owen, 'British Fossil Mammals,' on the Irish 

 elk, pp. 447, 455. 



3= 'Forest Creatures,' by C. Boner, 1861, p. 60. 



™ See the very interesting paper by Mr. J. A. Allen in 'Bull. Mus. 

 Comp. Zoolog. of Cambridge, United States,' vol. ii. No. 1, p. 82. The 

 weights were ascertained by a careful observer, Capt. Bryant. Dr^ 

 Gill in 'The American Naturalist,' Jan. 1871, Prof. Shaler on the rela- 

 tive size of the sexes of whales, 'American Naturalist,' Jan. 1873. 



2' 'Animal Economy,' p. 45. 



