Examining the Jaws that Power Some of the Strongest Bites in Natural History
Thylacoleo, the “marsupial lion”, had teeth designed like bolt-cutters that would spell doom for the giant kangaroos of its day.
Jaws are one of the most important evolutionary traits of the animal kingdom. They have been around since the armored fish of the Silurian Period some 440 million years ago. Since then they have changed shapes and functions, grown and retracted, but have always provided the key to animal survival. Without jaws, most vertebrate animals could not catch food, defend themselves, or even chew.
I have always had a fascination with the more menacing end of predatory animals. Large teeth attached to a scary animal’s maw tend to spark our collective imagination as evidenced by the fame of T. rex and the success of Jaws, aptly named for the fictitious sharks’ scariest feature. In this article, I will take a look at four of the strongest bites from the history of our planet, spanning the past 360 million years.
Dunkleosteus terrelli: : “The Shark-Splitter”
This painting of Dunkleosteus’ nightmare head armor is based on a fossil from the Field Museum in Chicago.
Period: Devonian (419 – 360 million years ago)
Place: North America
Long before sharks were the most feared creatures in the sea, Dunkleosteus terrelli and his armored fish brethren (a group called arthrodires) were the bullies of the ocean. With armor covering their heads and an estimated size of almost 20 feet, Dunkleosteus’ bite could severe early sharks and other armored fish into pieces. Their bites were even strong enough to dispatch each other in what must have been the must-see heavyweight bought of the Devonian period.
Instead of teeth, Dunkleosteus had fangs that were extended parts of the bony plates covering the skull. These fangs sharpened against each other every time the monster opened or shut its jaws. Dunkleosteus is considered to have one of the strongest bites ever thanks to these “self-sharpening fangs” and a morphological adaptation that overlooked the fish’s jaws growing longer and the fangs becoming sturdier as the creature aged into the dominant aquatic predator of its day. Based on a 2006 study, Dunkleosteus had a bite force of 11,000 pounds with the tip of the fang generating a nightmare inducing 80,000 pounds per square inch (psi), rivaling even the legendary bite of our next creature. What’s more, the study also estimated that the creature could open its death trap mouth in one fiftieth of a second, capable of sucking in smaller prey to a much slower death inside Dunkleosteus’ stomach.
With a bite this powerful and quick, Dunkleosteus was immune to everything in the sea except a larger Dunkleosteus. Skulls from the magnificent early kings of the ocean have been found throughout North America with holes inches deep, clearly from the fangs of another Dunkleosteus.
Tyrannosaurus Rex: “King Tyrant Lizard”
This Tyrannosaurus rex skull is based on the skull of the T-Rex dueling a Triceratops in the main hall of the Los Angeles Museum of Natural History.
Period: Cretaceous (145 – 66 million years ago).
Place: North America
The most famous predator to ever roam earth has the bite to back up the moniker “King Tyrant Lizard”. Its bite could not only subjugate any other dinosaur (even other tyrannosaurs) it came across, but it was strong enough to make bones literally explode when it clamped down on them.
A 2012 study constructed a 3D model of T. rex’s skull, complete with reconstructed jaw muscles using muscular information from both birds and crocodiles (birds are direct descendants of T. rex and other dinosaurs while crocodiles are a close cousin of the dinosaur group). This model led scientists to predict a maximum bite force of around 12,800 pounds (roughly their body weight), out-biting Dunkleosteus by 1,800 pounds. This bite force makes T. rex not only the king of the dinosaurs, but also the hardest biting land animal ever.*
The 2012 estimate for T. rex’s bite force is six to seven times that of another famous predatory dinosaur, Allosaurus, who ruled North America during the Jurassic period before the Tyrannosaur took the throne. The thing that sets T. rex’s bite apart is that the animal possessed large muscles that controlled the opening and closing of the jaws. These muscles would grow throughout the animal’s life, changing T. rex from an agile shallow-skulled predator to the bone-crushing top of the food chain as it matured. This had an important evolutionary advantage for the “king tyrant lizard” as juveniles hunted smaller animals and adults tackled the huge herbivores of the day, like Triceratops, reducing competition between the two.
But T. rex still had to fear other Tyrannosaurs. Similar to Dunkleosteus, when you’re the biggest, baddest creature around, even members of your own species are on the menu. In 2015, T. rex bones were found with tooth marks that patterned the mighty bite of another T. rex, concrete evidence of cannibalistic behavior in the tyrant lizard. When you’re at the top, it takes something pretty incredible to knock you off the summit. The bite of another T. rex is for sure incredible.
*Two ancient aquatic creatures have way more powerful bites estimates than T. rex. The prehistoric giant crocodile Deinosuchus, which preyed upon dinosaurs much like how crocodiles attack wildebeest today, had an estimated bite of 23,000 pounds. Megalodon, the largest shark ever, had an estimated bite force of 41,000 pounds, which comes in handy when hunting whales.
Thylacoleo carnifex: “Real-life Drop Bear”
Thylacoleo carnifex is nicknamed the “marsupial lion” for its big cat-like appearance and predatory prowess. In reality, it had a much more fearsome bite than even the king of the jungle.
Period: Pleistocene (2.6 million – 11,700 years ago)
Place: Australia
Thylacoleo carnifex is the largest carnivorous marsupial ever discovered. It terrorized a primeval Australia dominated by megafauna like giant kangaroos and rhino-sized wombat relatives. Many of these gargantuan creatures were the unaware target of a Thylacoleo ambush from above.
Based on a 2005 study, Thylacoleo had the strongest bite of any mammal to have ever existed. A large part of this has to do with the way its jaws and teeth were structured. Thylacoleo had enlarged, blade-like cheek teeth that developed in place of the posterior molars at the back of the animal’s mouth. In addition to the shearing blades at the side of its mouth, Thylacoleo also had huge incisors at the front of the jaw to stab its prey. Its skull was perfect for generating power. It was wide and heavy, with a short snout, and would have been packed inside thick muscles when the creature was alive.
As a marsupial, the fact that Thylacoleo had a much stronger bite compared to lions and tigers may not be as surprising as one initially believes. Some scientists believe that placental mammals, a group that includes most modern mammals from bats to humans, gave up some of the muscular strength in their heads as compensation for a larger brain cavity as they advanced past marsupials. Thylacoleo, a cold-blooded killer in a monstrous competition with giant lizards, thundering predatory birds, and terrestrial crocodiles (not to mention the brute strength of the massive animals on the menu), needed all the muscle it could get for its bite to move it to the top of the food chain. Placentals may have adapted smarter hunting strategies, but Thylacoleo was effective (at least until its prey disappeared during somewhat mysterious megafaunal die-off over the last 100,000 years) enough with pure biting power.
Thylacoleo needed all of this biting power because it was attacking creatures much bigger than itself. It also had another killer trait that was almost foolproof if the creature couldn’t get its jaws around something. It had a switchblade-like thumb claw that could disembowel its prey. They also relied on ambush and could drop down from trees at any second to dispose of a giant kangaroo. In this sense, they truly were real-life equivalents of the mythical predatory koalas known in Australian lore as “Drop Bears”.
Nile Crocodile: “Quick-Strike Kings of the Nile”
Nile Crocodile skull belonging to the dominant ambush hunter of Africa. Its jaws are capable of latching onto a wildebeest and dragging them into the water.
Period: Present Day
Place: Africa
We end our list with crocodiles, the dominant biters of today. Saltwater crocodiles, the largest living species of crocodile, have a bite force of 3,700 psi according to a 2012 study conducted on many different species of crocodilians at the St. Augustine Alligator Farm Zoological Park. The fact that the group has been around for over 85 million years is largely thanks to the effective and powerful bites that have helped them dominate the water’s edge.
Nile crocodiles (Crocodylus niloticus), in particular, have a ferocious snap to go with their long jaws and teeth. Some estimate their bite force at 5,000 psi, surpassing the slightly larger saltwater crocodile and American alligator for strongest living crocodile bite. In comparison, our bite generates a measly 162 psi. The Nile crocodile is closer to the lower range of a T. rex bite. Nile crocodiles can thank their large jaw abductor muscles that can “snap” their mouth shut in an instant when a wildebeest takes a drink from their watering hole.
The incredibly strong bite force is what unites all crocodiles and is what has helped them dominate their niche for longer than just about any other animal in our planet’s long and extraordinary history. They have also remained relatively unchanged with long jaws, studded with sharp teeth, lurking just below the water’s surface.
All artwork by Jack Tamisiea.
Sources:
https://www.earthtouchnews.com/discoveries/fossils/the-nasty-eating-habits-of-prehistorys-meanest-fish/
https://phys.org/news/2006-11-ancient-predator-strongest-fish-rivaling.html
https://www.smithsonianmag.com/science-nature/the-tyrannosaurus-rexs-dangerous-and-deadly-bite-37252918/
https://www.huffingtonpost.com.au/entry/t-rex-dinosaurs-cannibal_n_5637b12be4b00aa54a4efba0
http://news.bbc.co.uk/2/hi/science/nature/4409039.stm
http://news.bbc.co.uk/2/hi/science/nature/4409039.stm
https://news.nationalgeographic.com/news/2012/03/120315-crocodiles-bite-force-erickson-science-plos-one-strongest/
https://www.sciencefocus.com/nature/top-10-which-animals-have-the-strongest-bite/
