Did you know that there are two species of turkey? There's the tasty variety from North America (think Thanksgiving or sourdough bread and gravy), but there is also the ocellated turkey found only in the Yucatan peninsula of Central America.
Not much is known about this smaller bird. Though, we do know that the nodules found on this male's head will become more pronounced during mating season.
I'm so, so glad that humans don't exhibit a similar example of sexual dimorphism. If all human males had to distinguish themselves from females was face warts, our species would be in for a lot of trouble.