Image Gallery: Stunning Dual-Sex Animals

One bird's brain

This gynandromorph zebra finch has the orange check of a male on its right side, while its left side has female plummage. A study of its brain revealed differences between the male and female halves, indicating that sex identity was influenced by the genetic sex of the individual cells themselves.

On the wings

This rose-breasted grosbeak has the red wing lining of a male on one side and the yellow wing lining of a female on the other. It was captured during a bird banding effort.