Majungasaurus
Majungasaurus was a carnivorous dinosaur that lived in Madagascar during the Late Cretaceous, from approximately 70–66 million years ago when the asteroid impact wiped out the non-avian dinosaurs. Currently only one species is known – M. crenatissimus. It was a member of a group known as the abelisaurs - carnivorous, short-snouted theropod dinosaurs from the southern continents, best known for their stocky legs, highly ornamented skulls, and extremely reduced, almost useless forelimbs.
It was the largest carnivore in its Late Cretaceous ecosystem, even though it wasn't massive compared to other theropods. Madagascar was already an island at the time, and the landscape would have included seasonally dry floodplains, river channels, and flat coastal areas affected by rising seas. Sandy rivers occasionally flooded and rapidly buried animals, helping preserve their fossils.
It shared its environment with long-necked titanosaurs like Rapetosaurus, small meat-eating dinosaurs such as Masiakasaurus, early birds, mammals, and many crocodile-like predators - including some large, powerful species that may have competed with it around rivers and ponds.
Because Majungasaurus fossils are abundant at its site, scientists know more about its growth, variation, and behaviour than for most abelisaurids. Majungasaurus is unusually well known compared to most Southern Hemisphere predators, because scientists have fossils from many individuals of different ages, not just a single skeleton. Specimens include several well-preserved skulls, partial skeletons, and many isolated bones and teeth. Because so much of its skeleton is known from multiple individuals, Majungasaurus can be reconstructed with high confidence - especially compared to most Southern Hemisphere theropods.
When Majungasaurus was first discovered, only the top of its skull was known, and the small dome-like bump on this fragment led scientists to mistake it for a pachycephalosaur - the dome-headed plant-eaters - until more complete fossils revealed it was actually a carnivorous theropod.
Physical Characteristics and Anatomy
Majungasaurus was a medium-sized but powerfully built abelisaur, usually 5.6 - 7 m long and around 750 - 1,100 kg, with fragmentary remains hinting that some adults may have exceeded 8 m in length. Its shorter, stockier legs suggest it was a slower-moving predator than long-legged relatives like Carnotaurus, relying on close-range attacks or ambush rather than long, fast pursuits.
The skull is exceptionally well known from several nearly complete specimens, and shows the typical abelisaur design: short, tall, blunt-snouted, heavily textured, and noticeably wider than in most related species. A small horn-like dome rose from the top of the skull, and the fused nasal bones formed a thick, ridged structure; both were hollowed by sinuses to reduce weight and were probably covered in keratin or soft tissue for display.
CT scans show a relatively small floccular recess (a brain region involved in coordinating rapid head and eye movements) and inner-ear anatomy suggesting Majungasaurus held its head horizontally and was not specialized for fast side-to-side head turning - consistent with a predator focused on tackling large, slower prey rather than quick strikes.
Its teeth were short, strong, and numerous, with 17 in each upper and lower jaw segment - more than in most close relatives - and suited to repeated, forceful biting rather than slicing. The neck was very muscular and reinforced with interlocking ribs and ossified tendons, giving it the strength needed for powerful biting and shaking motions.
The rest of the skeleton followed a pattern typical of abelisaurs, with a long balancing tail, strong hips, fused ankle bones, and three weight-bearing toes on each foot. Majungasaurus had extremely reduced forelimbs, with a short upper arm bone, an immobile elbow, and four tiny fingers that lacked claws and formed a hand that was effectively immobile and non-functional. This extreme reduction reflects long-term evolutionary trends within abelisaurs, and the arms were likely of little use in hunting.
Feeding Behaviour and Cannibalism
One especially striking aspect of Majungasaurus is that it is the only non-avian theropod with clear, repeated evidence of cannibalism. Feeding bite marks on Majungasaurus bones show that it ate members of its own species, although these marks don't reveal whether it hunted them or simply scavenged already-dead individuals. One specimen also contains possible Majungasaurus bone fragments in its stomach region, but this evidence is more debated.
Its teeth were short, thick, and strong, well suited to biting into tough prey such as titanosaurs. CT scans of its inner ear suggest it had excellent balance and a stable, steady gaze - helpful for tracking large prey on open floodplains. Its skull bones were heavily sculpted with pits and grooves, giving it a rough, almost knobbly appearance in life.
Majungasaurus had a short, tall, and robust skull (about 60–70 cm long) that was broader than those of most other abelisaurs, giving it a very strong, deep-snouted head shape. Scientists think this skull shape reflects a different hunting style from most theropods: instead of delivering many quick bites, Majungasaurus may have used a bite-and-hold approach - clamping onto one area of prey and maintaining its grip. This idea comes from the strength of its skull and neck rather than any direct behavioural evidence.
Its reinforced skull bones, fused and thickened nasal region, and the single rounded horn on top of the head all contributed to a very strong, rigid skull able to withstand the stresses of holding onto large struggling prey. The "bite and hold" idea doesn't mean Majungasaurus immobilised giant sauropods; instead, its strong neck and deep, robust skull suggest a bite-and-hold tactic where it latched onto one area of the prey and applied repeated, focused damage rather than making long, slicing wounds.
The lower jaw had flexible joints and a large side opening, allowing slight movement between bones to reduce the risk of jaw fracture when gripping powerful prey. Its front teeth were thicker and more robust than the others to act as an anchor point in a bite-and-hold grip, while the low-crowned teeth overall were less likely to snap during struggles. Unlike the teeth of many theropods, which are curved on both edges, the teeth of Majungasaurus were curved on the front edge but straighter on the back edge - an arrangement that may have helped its teeth stay locked into prey during a prolonged bite.
Majungasaurus replaced its teeth extremely quickly, with full replacement cycles every 56 days - far faster than most carnivorous dinosaurs - which may reflect frequent tooth wear from biting bone and tough prey. Tooth marks on Rapetosaurus remains show that Majungasaurus fed on these large sauropods, whether through active hunting or scavenging. Its short, stocky hindlimbs suggest it traded speed for stability and power, which would have been effective for confronting slow-moving but massive sauropods. Studies estimating jaw-muscle forces suggest Majungasaurus had a moderate bite force, relying more on its strong skull and powerful neck than on sheer jaw pressure.
The rough, textured skull and thickened nasal region formed from mineralized skin tissue further strengthened the head and gave abelisaurs - including Majungasaurus - a characteristic rugged appearance. Skin impressions from close abelisaur relatives suggest Majungasaurus likely had pebbly, non-overlapping scales, although its exact skin texture is not directly known.
Growth, Variation, and Relationships
Fossils of individuals at many life stages show that as Majungasaurus grew, its skull became taller, more heavily fused, and more robust, while the eye sockets became proportionally smaller - evidence that juveniles and adults fed differently. Bone histology (studying growth rings inside bones, similar to tree rings) shows that Majungasaurus grew more slowly than many other large theropods, taking around 20 years to reach adulthood. This may reflect the strongly seasonal environment it lived in, where food availability rose and fell sharply each year; growing more slowly and steadily would have helped it survive frequent droughts or shortages by reducing the energy demands of rapid growth.
Younger individuals likely filled a mid-sized predator role, taking smaller animals until they grew large enough to tackle the big herbivores hunted by adults, although this is based on skull-shape changes rather than direct dietary evidence.
Majungasaurus is actually more closely related to the Indian dinosaur Rajasaurus than to the better-known Carnotaurus. This makes sense, because Madagascar and India were still joined as a single island for much of the Cretaceous. Their head crests also differ in a straightforward way: the horn of Majungasaurus is made mainly from bones on the top of the skull, while the horn of Rajasaurus comes mostly from bones over the nose.
References & Attributions
Image: Artistic reconstruction of Majungasaurus - The original uploader was ДиБгд at Russian Wikipedia., CC BY-SA 3.0, via Wikimedia Commons
Image: Size of Majungasaurus compared to a human - Eotyrannu5-Returns, CC BY-SA 4.0, via Wikimedia Commons
Image: Depiction of two Majungasaurus chasing Rapetosaurus. - ABelov2014 (https://abelov2014.deviantart.com/), CC BY-SA 3.0, via Wikimedia Commons
