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The Use of the Carnotaurus Horns

Mamerto Adan is a feature writer who is back in college once again. Science is one of his favorite topics.

Carnotaurus fossil

Carnotaurus fossil

Tiny Arms? No Problem

No matter how small their arms were, humans would cower at the sight of a therapod. Consider yourself condemned to be its next meal when you meet one. And thank goodness that no one was left to prowl on the surface of the planet. I mean bear attacks are bad enough, and no one is asking to die in the jaws of an Allosaurus. If we learned something from Jurassic Park and the terrible sequels that followed, we are easy dino snacks. So, make sure we have good restraints and a sturdy enclosure when we plan to clone one.

With that said, a Carnotaurus will give you a good fright when one comes your way. Hearing the name alone will strike fear (Meat-Eating Bull). Yes, it had those tiny arms. In fact, it had the puniest arm among therapods. T-rex had small arms too, but with large claws, robust bones, and strong muscles, the Tyrant Lizard King basically had lethal meat hooks. Carnotaurus, on the other hand, had overly tiny arms. The front limbs are just too small, and people thought that they are plain useless. Nevertheless, we don’t want to get close to a modern cassowary even though it had no front limbs. The same can be said of a large and quick dinosaur like a Carnotaurus.

And who needs front limbs if you got impressive horns.

Unique among therapods, Carnotaurus possess bony horns above the eye, hence it got that “flesh-eating bull” name. Yet we wonder why it had horns, and how it uses those horns? Curious, just read below to gore at the details.

At a distance, the arms are hard to spot

At a distance, the arms are hard to spot

Again, the sight of a prowling cassowary is enough to scare us. Its legs bearing deadly talons are more than capable of murdering annoying humans. This proves that any good-sized creature never needed powerful forelimbs to cause enough damage. With that said, the Carnotaurus never needed robust arms to wreak havoc among its prey. You might be wondering how the creature evolved with a nearly useless arm. In the cases of some therapods, small arms still had a purpose. To be fair the Carnotaurus radius and ulna bones are quite robust, while the hands could be strong. Nevertheless, it was never on par with the brutal arms of the T-rex, which it could have used as a weapon. In short, the Carnotaurus arms are nearly vestigial.

But in place of functioning arms, the Carnotaurus sports other hunting implements.

This large creature, around 30 feet in length, was built like a runner. The long hindlimbs were made for speed, as the thigh bone was adapted to withstand the bending moments of running. Scientists estimate that the creature had a top speed of 48-56 km per hour. Then there is the jaw. Some experts suggested that the animal did quick, but strong bites. But recently it was found that the Carnotaurus had twice the bite strength of the alligator.

With speed on its side and a considerable jaw strength, the Carnotaurus was able to dispatch large prey (sauropods)

And then it had extra features on its head. Those knobby horns.

The Horns

Carnotaurus skull, showing its horns

Carnotaurus skull, showing its horns

These are the unique body structure that earned the creature its name. The Carnotaurus horns aren’t exactly sharp. In fact, they are blunt aside from being short. If they had a keratinous covering, they will resemble bovid (buffaloes and related species) horns.

Those horns might be for display during mating. Dinosaurs are related to birds, and we see modern birds boast extra decorations when attracting mates. But by studying the skull structure, experts proposed other interesting functions of its horns.

The skull differs from other therapods its size. Large species like T-rex have longer skulls. In the case of the Carnotaurus, the skull is deeper and shorter. The orbital is proportionally smaller too. Having a shorter skull means the creature could execute quick head movements

And the head had robust support too.

The neck of the Carnotaurus boasts strong muscles. My friends wrestle, and they say that strong necks will prevent injury when you fall on your head. Going back to the Carnotaurus, the spinal column is also more rigid and quite strong.

Now, why did we have to go to all of this if the horns are our main focus? Because how the head was built could relate to the horn function, as what’s mentioned below.

Sparring and Hunting

Carnotaurus reconstruction

Carnotaurus reconstruction

Looking at the overall structure of the head and neck, the Carnotaurus could have used its horns for ramming. And these creatures gored each other during courtships, where males sparred against their rivals.

The skull itself is built to take blows, and again being short means the rapid head movement was possible. And two clashing Carnotaurus will need all those agile head motions during their butting contest. The small eye orbital also helped to avoid those nasty pokes. Lastly, the rigid spine and strong neck protect against shocks, because without them, the creature will end up with serious neck injuries

Other studies suggested that Carnotaurus pushed against each other rather than delivered head blows like rams. The horns, with their flattened upper sides, could distribute the compression force and prevent brain damage.

The horns were good sparring tools, but they might also be used during hunting. After all, this is a predator we are talking about. There is a possibility that the creature will resort to its horn to injure or kill its prey. With the jaws and teeth as the main weapon, the horns served as the sidearms.

Difficult to Know for Sure

We only have one specimen so far, and further discoveries could support or disprove what was proposed above.

Based on the skull structure, the neck and spine strength, experts could conclude that those horns are indeed for sparring match between males. Using the horns to hunt is another possibility, but again, only currently-undiscovered fossils can say for sure.


1. JMazzetta, Gerardo V.; Fariña, Richard A.; Vizcaíno, Sergio F. (1998) "On the paleobiology of the South American horned therapod Carnotaurus Sastrei Bonaparte."

2. JMazzetta, Gerardo V.; Fariña, Richard A.; Vizcaíno, Sergio F. (2004) "Giants and Bizarres: Body size of some southern South American Cretaceous dinosaurs."

3. Bonaparte, Jose F.; Novas, Fernando E.; Coria, Rodolfo A. (1990). "Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Middle Cretaceous of Patagonia."

Questions & Answers

Question: Why did the carnotaurus had spikes like armour all over its back?

Answer: Actually we could only make educated guesses for now, as we are dealing with a dead creature with limited remains to study. But it could be for protection or display, if we will refer to living creatures like birds (or reptiles).