Dinosaurs on the attack

The ability to overpower another animal requires a combination of strength, speed, balance and weaponry. Using weaponry such as claws can help to catch, hold and kill prey, while some theropod dinosaurs may have used other techniques such as filter-feeding to eat their food.

All theropod dinosaurs have the same general body plan – powerful lightweight frames, two relatively long legs, stiff counter-balancing tails and sharp claws – for this purpose.

However, theropods also vary in body size, arm length, skull structure and claw shape. This suggests they used different methods to overpower prey. By looking closely at these features, and comparing them to those of modern predators, we can detect what these methods may have been.

How do living predators attack?

Living predators vary widely in size and weaponry and use different techniques to attack prey. Some of these techniques may be similar to those used by dinosaurs. Examples include:

Cheetah: speed and agility
Crocodile: ambush tactics and strength
Eagle: strong claws, speed and agility

Examples of theropod attack styles

Some theropods like Albertosaurus and Giganotosaurus possibly attacked with a ‘bite and slice’ technique rather than going for an outright kill. This may have helped them prey on large sauropods.
Coelophysis bauri was a small theropod with a slender, lightweight skeleton and very long tail, for speed and agility in attack. A mass burial of over a dozen of these dinosaurs suggests they may have lived in packs.
The long forelimbs and curved claws of the spinosaur Suchomimus may have been used for ‘fishing’
Sinornithosaurus was an active and agile species that may have hunted in groups. It was probably adapted for leaping as its rigid tail acted as a counterbalance, allowing pinpoint accuracy and freeing the powerful feet claws. Whether this helped in attacking prey or leaping among tree branches is difficult to say. Sinornithosaurus was one of the first dinosaurs discovered with feathers.
Velociraptor was a small and agile meat-eater. One fossil specimen from Mongolia preserves it locked in death with its prey Protoceratops. There is no evidence that it hunted in packs, although some if its close relatives did. Velociraptor had many bird-like characteristics, including long arms, feathers and a wishbone. It had a specialised claw on the second toe that it held off the ground when walking. This claw may have been used to pierce or hold on to prey.

Using claws

Claws for killing?

Utahraptor, Velociraptor, Megaraptor and Deinonychus each had a specialised second toe with a massive claw used for killing prey. This toe had a joint that enabled it to move in a large arc, providing additional downward striking power to the claw. Although most scientists think this specialised claw was used to wield a killer slash, some believe it was designed to act like a grappling hook and latch onto prey. What do you think?

Claws for catching?

Suchomimus had long forelimbs with curved hand-claws. These were suited for scooping fish from the water towards its mouth, possibly like some bears do today. Dilophosaurus also had long arms and strong claws, and may have used these to help catch prey.

Another theropod that probably used its long forelimbs and claws for catching food was Bambiraptor. It had opposable fingers that could grip small prey – an unusual feature in dinosaurs.

Claws for subduing?

Allosaurus had large, strong claws on its hands and feet that may have held or subdued prey while it used its jaws and teeth to kill. These kinds of claws are typical of larger theropods.

Some large theropods such as Carnotaurus and Tyrannosaurus rex had large hand claws but very short arms that did not reach their mouths. These forelimbs may have been small, but the muscles were very strong. The arm length may be due to the massive heads of these theropods. An increase in head size relative to the body required a decrease in arm size to retain balance.

The odd ones out

Just when you thought you could tell a meat-eater by its sharp teeth and claws! The theropods described here have unusual features that make it difficult to determine what they ate. They include the beaked and toothless oviraptorosaurs, the ostrich-like filter-feeding ornithomimosaurs and the enigmatic therizinosaurs.

Modern animals that have similar feeding apparatuses include:

The Green Sea Turtle, which has a beak and skull of similar to those of oviraptorosaurs.
The Flamingo, which has a beak with filaments used for filter-feeding, similar to those of ornithomimosaurs.

Examples of 'odd' theropods

Therizinosaurus cheloniformis is a theropod with an impressive hand claw that looks savage but was possibly used for stripping vegetation, or ripping open termite mounds like echidnas and goannas do today. Therizinosaurus probably had a large, heavy build which suggests it was quite slow, and a beak with small teeth.
Oviraptorosaurs like Ingenia yanshini were meat-eaters with no teeth. They had relatively large heads with short, deep beaks and jaw muscles powerful enough to crush bones. They may also have eaten plants, molluscs and eggs.
Struthiomimus altus had beak-like jaws with no teeth. It may have fed by filtering food from sediments, like other ornithomimosaurs.
Ornithomimus edmontionicus fossils have been found with some soft tissues of their jaws preserved. These tissues are like those of some living water birds, such as flamingos, that eat by straining food from sediment.

Last Updated: 9 September 2009

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