Ostrich Penis Clears Up Evolutionary Mystery
Overlooked bird organ is similar to, but separate from, that of reptiles and mammals.
By Adam Marcus of Nature magazine
A long-running question about how the largest species of birds achieve erect penises seems to have been settled. In a study published this week in the Journal of Zoology, researchers report that male ostriches and emus enlarge their penises using a burst of lymphatic fluid rather than a blood vascular system like that found in reptiles and mammals.