Flamboyant and reclusive in equal measure, this iconic lizard can bluff like a poker champion. Here’s a brief introduction to the weird world of frilled dragons.
1. THEY’RE TREE DWELLERS.
Frilled dragons are native to the semiarid forests and grassy woodlands of northern Australia and southern New Guinea, and if you know what you’re looking for, the lizards can be easy to spot: Just look to the trees, where the creatures spend 90 percent of their lives. Frilled dragons press themselves vertically against a trunk and tend to stick their necks out at a 45-degree angle, making the lizards quite recognizable from afar. Once a predator wanders by, the dragon rests its chin against the bark, its gray-to-brown scales acting as camouflage.
2. WHEN UNFURLED, THE FRILL CAN BE A FOOT WIDE.
Like many lizards, frilled dragons have an insect-based diet supplemented with the occasional rodent or small reptile. But mealtime can be perilous. Though they spend much of their time safe in trees, hunting generally takes place on solid ground, where the dragons have a greater risk of getting hunted themselves. In the face of danger, a dragon’s first instinct is to either bolt toward the nearest tree or lie motionless. But if neither seems like an option, the reptile fights back with an underrated tool: deception.
The frilled dragon is named after the twin frills on either side of its head, which flare open when something invades the animal’s personal space. Ideally, this bluff will make the lizard appear twice as large as it truly is. From nose tip to tail tip, adult frilled dragons have a maximum length of 33 inches, but their foot-wide frill helps them look much, much bigger.
To enhance the performance, our dragon may hiss, rear up on two legs, and run at the marauder. Of course, some onlookers don’t buy this charade. If its big show doesn’t scare away the audience, the lizard will take off.
3. OPENING THE FRILL REQUIRES OPENING THE MOUTH.
Your tongue has an anchor called the hyoid bone, a small, u-shaped structure atop the Adam’s apple. Frilled dragons have two. They're long and rod-like. By flexing the muscles connected to these hyoids, a dragon can expand or contract its frill. For anatomical reasons, it can only pull off the frill-opening motion while also widening its jaws.
4. THEY’RE SOMETIMES CALLED “BICYCLE LIZARDS.”
It’s a cute nickname that’s inspired by the way frilled dragons run. When the reptiles rear up on their hind legs and zip around in bipedal fashion, they wheel both legs in a broad, circular motion.
Plenty of other saurians are known to move like this once in a while; when the big-headed, North American collared lizard does so, it almost looks like a miniature T. rex. Meanwhile, the basilisks of Central and South America are also called “Jesus Christ lizards” because they can stand up and run across bodies of water.
Why do lizards like frilled dragons rear up to run instead of cruising along on all fours? To find out, in 2008 an international research team set up a reptile gymnasium. They gathered specimens that represented 16 different types of semi-bipedal lizard, including the frilled dragon. Afterward, the team placed their subjects on miniature treadmills.
Footage of those workouts revealed surprising results. Apparently, the bipedal running style is less energy efficient than its quadrupedal alternative. However, many of the species they tested were able to accelerate faster on two legs than on four. In nature, a quick first step can be critical.
5. AUSTRALIAN CURRENCY USED TO FEATURE FRILLED DRAGONS.
Introduced in 1966, the 2-cent coin remained in circulation until 1992. On the front was a profile of Queen Elizabeth II; on the back, a frilled dragon with its tail curling and mouth agape. These coins became a huge collectors item … in Japan. After the lizard featured in a Japanese TV ad in the mid-'80s, sales of the coin skyrocketed to 20,000 to 30,000 a day with 2-cent coins going for 43 cents (100 yen) each.
6. THE FRILLS COME IN MANY COLORS.
In Queensland, the lizards usually have yellow or whitish frills, while those that live in Western Australia and the North Territory have red and orange ones instead. According to Thomas Merkling of Australian National University (ANU), certain insects contain pigments that can alter the shade of a lizard’s frill. If these prey items are consumed regularly, the appendages will become darker in color.
On top of looking great, vibrant colors might offer a combat advantage. In 2013, scientists from ANU and Macquaire University (MU) examined numerous fights between male dragons. They found that in 90 percent of these squabbles, victory went to the lizard whose frill was brighter. “Surprisingly, traits such as frill size, head size, and bite force did not predict contest outcome,” said MU biologist Martin Whiting. “Instead, males with brighter and more colorful frills were more likely to dominate opponents and take gold.”
7. IN VICTORIAN TIMES, THE DRAGONS WERE ROPED INTO AN EVOLUTIONARY DEBATE.
Sometimes known as “Darwin’s bulldog,” Thomas Henry Huxley (1825–1895) was a passionate defender of evolutionary theory. A respected anatomist, he was among the first scientists to ever suggest that there might be a link between birds and reptiles.
Huxley found a supporter in Johan Ludwig Gerard Krefft (1830–1881). In 1870, Krefft—then the curator of Australia’s National Museum—told the Sydney Morning Herald that he’d written Huxley about the frilled dragon, describing it as “a lizard which would squat on its hind legs, and even hop in a manner not unlike a bird.” Could this species help prove Huxley’s hunch?
Huxley asked another scientist to investigate further.Huxley’s recruit was marine biologist William Saville-Kent (1845-1908). After scrutinizing the anatomy and behavior of the lizard, Saville-Kent concluded that neither its skeleton nor habits were all that bird-like—much to his own disappointment. Still, history has vindicated Huxley: A tidal wave of evidence now indicates that our feathered friends are descended from those most celebrated of reptiles, the dinosaurs.
8. NEST TEMPERATURES DICTATE THE SEX OF UNBORN HATCHLINGS.
Eggs kept at 26°C overwhelmingly yield female babies, while clutches that are continuously exposed to a temperature of 29°C produce males and females in about equal measure. Biologists call this phenomenon temperature-dependent sex determination, or TSD. It’s something that a great many reptiles—including alligators and red-eared slider turtles—have to contend with.
9. FRILLED DRAGONS BELONG TO AN EXTREMELY DIVERSE GROUP.
The agamid family includes more than 350 species that come in every oddball shape you could ask for. Consider, for example, the aptly-named “flying dragons,” which use their elongated ribs and specialized skin flaps to glide between trees. Australia’s thorny devils are burrowing, color-changing ant-gobblers that are covered with spikes. Over in the Philippines, you may encounter a gang of large, semiaquatic omnivores known as sailfin lizards. And pet stores all over the world now stock the ever-popular bearded dragons. When threatened, these little creatures expand a pouch on the underside of their throat that’s covered in tiny spines. Fortunately, captive-bred “beardies” tend to be quite docile.
10. THEY INFLUENCED ONE OF JURASSIC PARK’S MUTANT DINOSAURS.
Never underestimate a genetically-modified dinosaur. After killing the electric fences in Jurassic Park, the vile Dennis Nedry (played by Seinfeld’s Wayne Newman) gets his comeuppance from a poison-spewing Dilophosaurus. Right before it pounces on him, the beast unfurls an oversized, retractable frill—which strongly resembles the namesake attribute of a certain Australian lizard.
In reality, there’s no evidence that Dilophosaurus—or any other dinosaur—had such an apparatus. Still, the man who originally named this animal back in 1954 didn’t seem to mind Jurassic Park’s little inaccuracies. “It was quite a thrill to see Dilophosaurus as an actor,” raved paleontologist Sam Welles. Though he admitted that the dinosaur’s neck vertebrae would have been incompatible with a frilled dragon-style hood, Welles dismissed his own critique as a minor point. “I enjoyed the movie thoroughly,” he said.