Prehistoric Frog Had a Monstrous Bite

Experts theorize that the *Beelzebufo*'s diet included small crocodylians and baby dinosaurs. CC Nobu Tamura

In 1993, the year "Jurassic Park" hit theaters, scientists uncovered the first known remains of an amazing predator that might've eaten the occasional dinosaur. At the time, a team of fossil-hunters led by paleontologist David Krause was exploring Madagascar. There, they discovered some isolated bones and fragments from a gigantic, 70 million-year-old amphibian. "We knew [the fossils] belonged to a frog because of their morphology," Krause says in an email, "but we were stunned by their size."

Clearly, the material represented a new species. Out in the field, Krause's group gave their critter an informal-but-fearsome nickname: "The frog from hell." It fit.

Since '93, a trove of new remains from this plus-sized hopper has come to light, including a partial skull and skeleton. We now know that the animal could measure up to 16 inches (0.4 meters) long from the tip of its nose to the end of its spinal column. Also, some estimates put its maximum weight at 9 pounds (4.08 kilograms) or more. By comparison, the biggest living frog — the so-called "Goliath frog" of west Africa — is about 4 inches (0.1 meters) smaller and 1 to 2 pounds (0.45 to 0.9 kilos) lighter.

Nowadays, the creature goes by an official, scientific moniker: Beelzebufo ampinga. Translated from Greek and Latin, Beelzebufo means "devil toad." Meanwhile, ampinga is the Malagasy word for "shield" — a reference to a set of armor plates on the creature's back.

Experts believe the frog had a varied diet. Madagascar's fossil record shows us that birds, lizards, snakes and small mammals were all readily available in Beelzebufo's day. Furthermore, given the opportunity, it would've almost certainly eaten small crocodylians and even baby dinosaurs. But how did Beelzebufo overpower such prey? Jaw strength no doubt played a major role. Indeed, according to some recent research, the "devil toad" had one hellish bite.

Peering at Pacman

In September 2017, Scientific Reports published a new paper on the jaw mechanics of Beelzebufo's closest living cousins. South America is home to a group of strange-looking amphibians called the horned frogs (genus Ceratophrys). Named after the fleshy, pointed ridges that sit above each eye, these guys also have comically large mouths. Hence, they're sometimes sold in pet stores as "Pacman frogs."

Pacman frog, South American horned frog — The South American horned frog, aka the Pacman frog, also has a tremendous bite force.
Kristopher Lappin

Laugh all you like, but mind your fingers; horned frogs can dish out painful bites! For an amphibian, this is a strange talent. Most frogs, toads and salamanders have very weak jaws and rarely bite in self-defense. However, horned frogs are punishing biters who aren't the least bit shy about latching onto would-be attackers.

Intrigued by this behavior, a team of researchers led by herpetologist Kristopher Lappin decided to figure out just how forceful the Pacman's bites can be. Their findings, as chronicled in that paper, broke some exciting new ground.

Sean Wilcox, a Ph.D. candidate at UC Riverside, was a co-author in the study. He says science has mostly ignored the topic of amphibian jaw strength. "Much research has been done on the bite force in larger terrestrial vertebrates," he says via email, "but no studies had attempted to measure bite force in frogs [before]."

A Window to the Past

To help fill that gap in knowledge, Lappin's team rounded up eight Cranwell's horned frogs (Ceratophrys cranwelli). The amphibians were coaxed into biting an electric force transducer, which is a clamp-like instrument used to quantify compression forces.

A correlation was found between an individual frog's body measurements and the power of its bite. For example, a small frog with a head measuring just 1.8 inches (or 45 millimeters) across could be expected to put out 30 Newtons' worth of force. To get a sense of how this might feel, try to balance just over 3 quarts (or 3 liters) of water on your fingertip. Now let's up the ante.

Imagine how painful it might be if you had to balance a whopping 13.47 gallons (or 51 liters) on the same fingertip. According to the researchers' estimates, that would be comparable to a bite from the largest existing Ceratophrys frogs, whose heads are just under 4 inches (0.1 meter) wide. By Lappin and company's calculations, such an animal can administer around 500 Newtons when it chomps down.

What does this have to do with Beelzebufo? Well, anatomical evidence indicates that Ceratophrys frogs are the extinct behemoth's closest living relatives. Knowing this, Lappin's team used the data collected from their eight research amphibians to assess Beelzebufo's potential jaw strength. In their estimation, big adults could deliver a devastating, 2,200-Newton bite.

Put another way, the devil toad's bite force was stronger than a gray wolf's and on par with that of a female tiger. Memo to time-travelers: Never mess with a Beelzebufo.

In hindsight, the revelation that this species had such an impressive maw shouldn't come as a surprise. The clues were right there in its skeleton all along. Like our beloved Pacman frogs, Beelzebufo had a huge, wide skull with ample room for strong jaw-closing muscles.

Nonetheless, the devil toad and today's horned frogs had their differences, too — apart from the obvious size disparity. "There is no evidence that Beelzebufo had pointed horns above the eyes and the skull was longer and shallower," study co-author Marc Jones says in an email.

On the other hand, Beelzebufo probably shared certain habits with its modern counterparts. As we've discussed, horned frogs use their mouths to ward off attackers. But the jaws are also great for subduing prey items. Taking a "sit and wait" approach, Pacman frogs hide out in mud or leaf litter, capitalizing on their camouflaged skin. Once a target wanders by, a horned frog springs into action. Using its extremely sticky tongue, the amphibian can ensnare most prey items with ease. And after a meal is caught, those vice-like jaws render escape practically impossible.

Just picture a baby dinosaur suffering this fate 70 million years ago, its body caught between a set of jaws that could put a gray wolf's to shame. Might make for a scary scene in "Jurassic Park 5".