The Blue-footed Booby is a marine bird in the family Sulidae, which includes ten species of long-winged seabirds. Blue-footed boobies belong to the genus Sula, which comprises six species of boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait. Males display their feet in an elaborate mating ritual by lifting their feet up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm (36 in) long with a wingspan of up to 1.5 m (4.9 ft).