coloured in
both sexes; or which, from their organisation and habits, do 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 curious cases in which the female bird is actually
more brilliant than the male, and which yet have open nests. Such are
the dotterel (Eudromias morinellus), 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.[124]

_Sexual Colours of other Vertebrates._

We may consider a few of the cases of sexual colouring of other classes
of vertebrates, as given by Mr. 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, spines, or other
appendages, and in some few cases the colours are decidedly different.
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 ornaments 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 difference 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
colours, as so many insects and birds have certainly done.[125]

In mammalia there is often a somewhat greater intensity of colour in
the male, but rarely a decided difference. The female of the great red
kangaroo, however, is a delicate gray; while in the Lemur macaco of
Madagascar the male is jet-black and the female brown. In many monkeys
also th