Charles Darwin, the renowned biologist who wrote entire books on evolution, proposed that due to ferocious competition amongst males to find female partners, some species have evolved into having more than one kind, or morph, of gender. In the eyes of an alpha male, this morphing allows the animal to appear as less of a threat. Below are ten animals that are transgendered or multi-gendered within the animal kingdom . Over 40 percent of Marsh Harriers will spend their entire lives with feathers that are seen on females. These males are about 30 percent smaller and lighter than normal males of the species. Female-looking males are also less likely to be attacked by bigger males, and also refrain from fighting with each other.