X COLOURS AXD ORXAMEXTS CHARACTERISTIC OF SEX 281 



not require special protective coloration, such as many of 

 the birds of prey, the larger waders, and the oceanic birds. 



There are a few very carious cases in which the female 

 bird is actually more brilliant than the male, and M'hich yet 

 have open nests. Such are the dotterel (Eudromias morinel- 

 lus), several species of phalarope, an Australian creeper 

 (Climacteris erythropus), and a few others ; but in every one 

 of these cases the relation of the sexes in regard to nidification 

 is reversed, the male performing the duties of incubation, 

 while the female is the stronger and more pugnacious. This 

 curious case, therefore, quite accords with the general law of 

 coloration.^ 



Sexual Colours of other Vertebrates. 



We may consider a few of the cases of sexual colouring of 

 other classes of vertebrates, as given by J\Ir. Darwin. In 

 fishes, though the sexes are usually alike, there are several 

 species in which the males are more brightly coloured, and 

 have more elongated fins, spmes, or other appendages, and in 

 some few cases the colours are decidedly difierent. The males 

 often fight together, and are altogether more vivacious and 

 excitable than the females during the breeding season ; and 

 with this we may connect a greater intensity of coloration. 



In frogs and toads the colours are usually alike, or a little 

 more intense in the males, and the same may be said of most 

 snakes. It is in lizards that we first meet with considerable 

 sexual differences, many of the species having gular pouches, 

 frills, dorsal crests, or horns, either confined to the males, or 

 more developed in them than in the females, and these orna- 

 ments are often brightly coloured. In most cases, however, 

 the tints of lizards are protective, the male being usually a 

 little more intense in coloration ; and the difi'erence in extreme 

 cases may be partly due to the need of protection for the 

 female, which, when laden with eggs, must be less active and 

 less able to escape from enemies than the male, and may, 

 therefore, have retained more protective coloui^s, as so many 

 insects and birds have certainly done.- 



In mammalia there is often a somewhat greater intensity 



^ Seebohm's History of British Birds, vol. ii., introduction, p. xiii. 

 " For details see Darwin's Descent of Man, chap. xii. 



