Carnotaurus
Carnotaurus was a large carnivorous theropod dinosaur that lived in what is now Argentina during the Late Cretaceous period, from around 72 to 69 million years ago. Currently, only one species is known – Carnotaurus sastrei – which was first described in 1984 by Argentine paleontologist José Bonaparte. To date, this is the only skeleton that has been found of Carnotaurus, but fortunately, this one specimen was relatively complete and well-preserved. The name Carnotaurus means "meat-eating bull" - a reference to the dinosaur's bull-like horns.
Carnotaurus belonged to a group of dinosaurs known as abelisaurs. These were carnivorous dinosaurs that possibly emerged in the Late Jurassic and thrived during the Cretaceous on the southern supercontinent Gondwana. Other members include Abelisaurus, Rajasaurus, and Majungasaurus.
Skeletal Features and Limbs
Certain parts of the skeleton are missing, such as the latter two-thirds of its tail, its lower legs, and feet. This means that we can't know exactly what these parts looked like in Carnotaurus unless further specimens are discovered. However, scientists can make educated guesses based on the remains we do have, as well as from close relatives of Carnotaurus.
Abelisaurs had short, deep skulls - often adorned with horns or crests - giving them a distinctive "pug-faced" appearance. Their arms were extremely short and essentially useless. While the short arms of Tyrannosaurus rex are often joked about, they were still larger than those of abelisaurs. Carnotaurus had four fingers in total, but only the middle two had full bones. These fingers were fused, immobile, and likely clawless. From the outside, the hand may not have even looked like it had separate fingers at all.
Skin and Appearance
Unusually - and fortunately, given that only a single specimen has been discovered - several extensive skin impressions were also preserved. These include skin from the lower jaw, neck, shoulders, tail, and along the rib cage. All impressions show evidence of scaly skin, with no indication of feathers.Carnotaurus had randomly distributed scales across its body, rather than neatly arranged rows as once thought. There was a mix of small base scales and larger, irregular bump-like feature scales that may have played a role in protection or thermoregulation. The true color of Carnotaurus remains unknown.
Horns and Their Function
One of the most unusual and eye-catching features of Carnotaurus is the pair of thick, conical horns above its eyes, likely covered in keratin sheaths. While some other meat-eating dinosaurs had small horns or ridges, the horns of Carnotaurus were much more dramatic.Instead of pointing straight up, these horns swept outward and upward from the middle of its skull, almost like those of a bull. Compared to the size of its head, they were the largest horns seen in any theropod. The exact function of these horns is still unclear, but it is thought they may have been used in combat with other Carnotaurus, perhaps in head-to-head shoving matches using their robust neck muscles and reinforced skulls. Others propose the horns were used for visual display or intimidation. While it’s been suggested they could have been used to injure prey, this idea is less supported, as no known predators use horns in this way.
Size and Body Structure
Despite these traits, the overall body plan of Carnotaurus was typical of theropods, with a long, low body held horizontally and supported by strong legs. The one known specimen measured around 8 meters long from head to tail, and stood approximately 3 to 3.5 meters tall at the hips. Weight estimates vary, ranging from approximately 1,300 kg to 2,100 kg depending on the methods used.
Feeding and Hunting Behavior
The feeding behavior of Carnotaurus is still debated. Some scientists believe it preyed on smaller, fast-moving animals, using quick, not especially powerful bites—ideal for snapping up small prey. Others argue that it may have hunted much larger animals, including massive sauropods, ambushing them and using its jaws to deliver deep, slashing wounds.The debate partly hinges on how strong its bite actually was. Some studies suggest it had a flexible lower jaw allowing it to swallow smaller prey whole, while others argue it had a powerful bite—possibly even stronger than that of a modern alligator - more suited to attacking large dinosaurs.
Speed and Locomotion
Carnotaurus also had a thick, muscular tail that powered strong leg movements, making it one of the fastest large theropods. However, its stiff tail likely limited its ability to turn sharply. All this suggests Carnotaurus was a powerful and versatile predator, possibly hunting anything it could catch - big or small - and perhaps also scavenging when the opportunity arose.Senses and Brain Structure
Studies of its braincase using CT scans reveal that Carnotaurus had large olfactory bulbs, indicating a strong sense of smell. These bulbs were angled downward, possibly helping it track scents more effectively than other relatives. In contrast, its optic lobes were small, suggesting that vision wasn’t its strongest sense. It likely didn’t hear very well either, as evidence suggests it could only detect low-pitched sounds.Interestingly, Carnotaurus had a well-developed flocculus, a part of the brain that helps animals stabilize their gaze when moving quickly. This implies that it relied on fast, coordinated movements of the head and body—potentially useful for tracking prey or reacting to its surroundings.
While smell was likely its strongest sense, Carnotaurus also had slightly forward-facing eyes, giving it some degree of depth perception, which would have been helpful in judging distances while hunting.
Habitat and Environment
Carnotaurus lived around 72 to 69 million years ago in what is now the La Colonia Formation of Argentina. This was a coastal, seasonal environment featuring estuaries, tidal flats, and patches of forest. The region was rich in freshwater sources and vegetation, quite different from the arid badlands often depicted in popular media. It shared this habitat with a variety of other animals, including titanosaurs, turtles, snakes, birds, and early mammals.References & Attributions
Image: Reconstruction of Carnotaurus - Fred Wierum, CC BY-SA 4.0, via Wikimedia Commons.png){kind=link}
Image: Size comparison of Carnotaurus to a human - Fred Wierum, CC BY-SA 4.0, via Wikimedia Commons
Image: Skull cast of Carnotaurus - AStrangerintheAlps, CC BY-SA 3.0, via Wikimedia Commons
Image: Illustration of Carnotaurus showing the bones that have been found - Jaime A. Headden (User:Qilong), CC BY 3.0, via Wikimedia Commons
