Howdy lizardsandfriends followers,

My name is Faith, and I’ve worked in the Lizard Lab for the past two years. (Check out my previous blog posts here and here!)  In this post, I’ll describe how we can tell the difference between male and female anoles. If you live in the southeastern United States, the Caribbean, or Central or South America, you may have caught an anole and wondered if it was a boy lizard or a girl lizard. Here’s how to tell!

Female green anole on the left, and male on the right. Note the male’s large dewlap! (Click on the picture to make it bigger.)

 

Both male and female anoles perch on trees, eat insects, move around a lot, and change colors. As a result, it can be difficult to determine the sex of an anole. Lucky for us though, anoles are sexually dimorphic – this means that males and females have distinct traits that we can use to tell them apart, especially if you can look at the lizard up close. (Some of these traits also help us tell males and females apart in other types of lizards too, but some of these traits only apply to anoles.)

  1. Check the body size of the anole. Adult males grow to be bigger than adult females. If a male isn’t fully grown yet, he may be the same size as a female, but if you see a really big anole, it’s probably a male.
  2. Look at the lizard’s throat. Male anoles have a big dewlap, a colorful throat fan used to communicate with other lizards. Although some female anoles also have dewlaps, they are usually lighter colored and much smaller.
  3. Check the lizard’s tail. Male green anoles (Anolis carolinensis) and males of some other species have two scales much larger than their other scales at the base of their tails. These are called “postanal” scales. You may need a magnifying glass to see these scales on a small lizard, but the presence of these scales on a green anole is a sure sign that you have found a male.

 

In green anoles, males (left) have enlarged postanal scales (the yellow arrows point to these enlarged scales). In females (right), all postanal scales are the same size. (Click on the picture to make it bigger.)

In addition to how the lizard looks, you may also be able to determine the sex of an anole from how it behaves.

  1. Males are often more aggressive than females. If you find two lizards in the middle of a fight, and you see lots of dewlap displays, push-ups, head bobbing, and biting, then you have most likely found two males. Females will also fight with other females, but they don’t do this very often, and they aren’t usually as aggressive as males when they fight.
  2. Males use courtship behavior around females, trying to attract them to mate. The displays that males use in competing with other males are the same types of displays they use to attract females – dewlap displays, push-ups, and head bobs. Females may head bob in return, but this is not always as obvious.

Next time you see an anole, use these tips to help you figure out if it’s a boy or a girl!