By Alisha Brewer
Have you ever wondered down the winding paths of the zoo, eyes peeled, hoping that you would be one of the lucky ones who finds the elusive, yet absolutely beautiful, peacock feather? If luck was really on your side then you’d witness first hand a male displaying his bright and brilliant feathers. Flashes of electric blue and green cascading down like a firework as he carefully dances around a female. Did you ever stop to take a look at the details of the female? Can you even picture what a peahen looks like? It’s hard to take note of such extraneous things when you are being dazzled by a spectacular display of colors. (Don’t feel bad, the peahens think so too.) Peahens are mostly cream and brown, rather dull when compared to their male counterparts. This is the perfect example of, here comes the buzz word, sexual dimorphism.
Sexual dimorphism is a physical difference between the sexes of a species beyond their reproductive organs. It can be a difference in color, size or weight. Sometimes sexually dimorphic animals can be > quite obvious, like peacocks or lions (males have the big bushy manes and the females do not). But sometimes the variance between sexes can be subtle. In the bird species, Great Hornbills, both sexes look nearly identical in stature. However, females have crystal blue eyes whereas males have red eyes. They weren’t kidding when they said that the eyes are windows to the soul.
So how about sexual dimorphism a little closer to home. What about in our own backyards? While relaxing on your patio or taking a walk around your neighborhood have you ever seen a flash of red go streaking by? That’s right! Our very own Northern Cardinals are a great example of sexual dimorphism. The males are bright red with little black faces. The females however, are an olive brown color. While hiking in the Chiricahuas or driving the road towards Colossal Cave have you ever seen a Mule Deer? Bucks have impressive antlers to show off, while the does are a bit smaller and do not have antlers. What other sexually dimorphic animals can you think of? Quail? Black widow spiders? If you keep your eyes open, there are examples all around you!
So why does sexual dimorphism exist? It all comes down to breeding and survival. In many cases larger, stronger, brighter males can be more apt to attract a female’s attention and keep competitors at bay. If a female is smaller and duller in color it can act as a perfect camouflage while she is sitting on her nest or moving to and from her den. Drawing less attention to yourself is a great way to keep unwanted visitors away from your little ones.
The differences between sexually dimorphic animals can be extreme or slight, bright radiant colors or a few extra pounds. It’s those differences that can attract a mate or protect a family. Isn’t it interesting how it’s their differences that bring them together?
Just food for thought.
