What a Lizard Poop of Epic Proportions Is Teaching Scientists

In Homer’s Iliad, Achilles must choose between a mediocre but comfortable life and one that will end in his untimely death but immortal glory. And so it was with the case of a curiously distended curly-tailed lizard found in a parking lot behind a pizza joint in Cocoa Beach, Florida.

Most curly-tailed lizards are not worthy of an epic poem. They have neither huge fangs nor venom. They grow no larger than a candy bar.

But this female curly-tailed lizard, her abdomen chock-full of poop, will be remembered forever—not for leading the charge on an impenetrable city, but for possessing the largest feces-to-body-mass ratio ever recorded in a living animal.

"Silly Putty-Like Mass"

The saga begins on July 21, 2018, when Natalie Claunch—a Ph.D. candidate at the University of Florida's School of Natural Resources and Environment—and her crew rose early to go hunting for lizards as part of a study about invasive species. Curly-taileds are native to the islands of the Caribbean, which means their presence in Central and South Florida could have dire consequences for native wildlife.

That fateful morning, the scientists were in a race against Helios, the sun-god, and his sky-traversing chariot of fire. Lizards are “thermally constrained,” Claunch tells Mental Floss, which means that by about high noon, most will disappear underground to wait out the heat of the day. And so each field assistant was working hard to nab as many lizards as possible with tiny nooses attached to 20-foot poles.

Then, at 10:41 a.m., it happened. An assistant trotted back from the frontlines holding a curly-tailed lizard shaped like one of Aphrodite’s beloved pears. Someone suggested perhaps the creature was pregnant, but after a few palpations of the Silly Putty-like mass, Claunch knew the critter was not full of jellybean-sized eggs. Indeed, the fates had spun a thread for her that was far worse. From her shoulder blades to her pelvis, this particular curly-tailed lizard harbored an oval-shaped deuce that accounted for a whopping 78.5 percent of her total body weight.

For reference, that would be like a 150-pound human carrying around a gut full of nearly 118 pounds of hard, impassable poo.

The previous poop-to-body-mass record holder, by the way, was a Burmese python in Florida described by Dickinson College herpetologist Scott Boback in 2016 [PDF]. "I'm more than happy to pass along the torch to Natalie Claunch for discovering the world's largest turd," Boback tells Mental Floss.

Leiocephalus carinatus
by Blackburn Lab
on Sketchfab

The stupendous stool took up so much physical space in the lizard’s body cavity, her liver and ovaries were “visibly atrophied,” Claunch wrote in a note published in the journal Herpetological Review.

By all accounts, the lizard’s condition must have been excruciating. So what in the name of the gods could lead to such a monstrous state?

A Taste For French Fry Grease

Claunch believes the lizard had been prowling around the pizza parlor’s grease bin, which had a tendency to drip into the sand below. Perhaps the reptile had developed a taste for old French fry oil, or maybe she’d learned to gulp down the insects that landed upon it, but somehow, she’d acquired a belly full of sand and dirt in the process. And while food kept going in, the lizard no longer seemed capable of squirting it back out again.

“There’s also an anole skull in there,” says Claunch, noting that curly-taileds sometimes devour brown anoles, which are also invasive.

Boback praised both Claunch's and the lizard's fortitude. "Clearly she searched far and wide, knee-deep in the muck, to discover yet another squamate [scaled reptile] with a magnum rectum, capable of consuming enough greasy cheese fries to develop a poop almost the size of herself," he says.

The reason we know so much about one lizard’s weird poop is Florida state law prohibits anyone from releasing invasive species back into the wild. So after humanely euthanizing the impacted reptile, Claunch drove it over to Ed Stanley, an evolutionary biologist at the Florida Museum of Natural History, to take a closer look.

Stanley has been called the “sultan of scan” for the way he uses an x-ray technology called Micro-CT to reveal the inner workings of everything from chameleon eyeballs and hidden parasites to deep sea creatures. And after one look at the curly-tailed lizard, he too wanted to take a peek inside.

While some might think scanning giant turds is a crappy way to spend one’s time, Stanley sees his efforts as a way to democratize science. In fact, he’s part of a larger, ambitious effort, called oVert, to create 3D models of every vertebrate genus currently held in American museum collections.

What the Turds Tell Us

Museum collections are full of rare, important specimens that simply can’t be lent out to every high school science class that might want to dissect them, according to Stanley. But with 3D models that allow you to illustrate everything from an animal’s circulatory system to its bones, skin, and organs, “it lets us put the specimens in the hands of people who might not otherwise be able to see them,” Stanley tells Mental Floss. He’s had everyone from scientists to animators and artists use his scans for reference.

The best part is, thanks to this modelling technology, you don’t need any credentials to go poking around the curly-tailed lizard’s guts any time you get a hankering. Just be forewarned, it’s easy to get lost in there. “It’s like The Magic School Bus,” Claunch says.

Of course, there are plenty of scientific reasons to scan scat.

Impacted poops are commonly thought of as products of a life spent in captivity, but the giant warrior queen with a gut full of skull and sand proves that it can happen in the urban wild, too. And this may hold insight for exotic vets, according to Claunch. Likewise, Stanley says he’d like to go back and scan the reptile again, this time with contrast agents, to better compare how the animal’s body accommodated such a fantastic fecal mass.

And now that the model is available on the internet, immortalized in pixels, other scientists could use it to discover, well, who knows what?

A curly-tailed lizard has crossed over to the Elysian Fields and into the stuff of legend. For it was Homer who once wrote, “Any [bowel movement] might be our last. Everything is more beautiful because we are doomed.”

Her existence was ephemeral, but her excreta shall be eternal.