Snake Sneakers

The three-eyed snake warns The Dry is coming!

Our Rangers found a three-eyed snake on the Arnhem Highway near Humpty Doo just out of Darwin. It was a juvenile, approximately 40cm long.

The snake is peculiar as an x-ray revealed it was not two separate heads forged together, rather it appeared to be one skull with an additional eye socket and three functioning eyes.

This is a New Mexico Whiptail Lizard (Aspidoscelis neomexicanus), and I am 100% sure that this lizard is a female! How can I know? 

Well, because every New Mexico Whiptail Lizard is a female!

There are about 45 species of whiptail lizards (which used to be one genus but then were sorted mostly into the genera Aspidoscelis and Cnemidophorus), at least 15 of which are “unisexual” species, i.e. all-female species. 

(some species are fun colours!)

These lizards reproduce exclusively via parthenogenesis, which basically means they clone themselves every time they reproduce, laying eggs that contain genetically-identical offspring. Now, normally I would call such a species asexual lizards, to get some of that good ace rep, but here’s the thing:

These all-female lizards still mate with each other.

(gal pals! 😉)

Every breeding season, these lizards go through same-sex mating behaviours, including lengthy courtship rituals, which culminates in one female lizard mounting the other. 

This process can last more than 10 minutes.

(I love this paper)

Without same-sex mating, a female might lay one or two eggs in a breeding season. Maybe. With same-sex mating, a female can lay up to 9 eggs in a season! That’s 2-3 clutches with 2-3 eggs in each, and a HUGE increase in reproductive success!

A BBC clip about these lizards from 2010 claims that the “male-like” behaviour of the females is caused by an increase of “the male hormone testosterone”, but that’s actually not true. At all. 

The BBC lied to me about Lesbian Lizards!!!

In reality, testosterone levels stay uniformly low throughout the breeding season, while the cycling of estrogen and progesterone are what triggers the different mating behaviours. Neither of these hormones are generally referred to as “male” hormones. 

(git gud, BBC. Honestly, this 2 minute clip has a bunch of mistakes, mostly to increase the Drama, but whatever, I guess). 

(one of my favourite graphs in anything, tbh)

Before the ovulation, the lizard’s levels of estrogen increases, leading to “female-like” mating behaviour. After mating, but before the eggs are laid, estrogen drops off a clip while progesterone peaks, and the female goes off to mate with other females, this time in the “male-like” role.

(This one is A. exsanguis, which is fun because it’s name means “lacking blood” although I am 99.999999% sure that they do have blood)

Once the eggs are laid, the female has a period of inactivity, probably because laying eggs is a lot of work and she doesn’t have the TIME or ENERGY to deal with the ups and downs of courtship. 

(Seriously, though, it probably is a way to recover after the metabolically-taxing work of reproduction. Let the new mom REST).

This has been Fun Fact Friday, telling you the story of the Lesbian Lizards because I love lesbian lizards so much you guys you don’t even know.

Also, my city celebrates Pride in August, so Happy Pride to All! (But especially to Lesbian Lizards, my beloved)

Oh, look. More Sources:

They are also very very teeny tiny. I have tried to convey this by showing one eating a fruit fly (you can see the wings sticking out of her mouth) and one next to small water droplets.