It's difficult to work out the intelligence of animals that roamed the land in the Mesozoic Era – which began around 252 million years ago – but scientists have their theories...
One way to measure intelligence is by encephalisation quotient (EQ), the ratio of brain to body size.
Plot those sizes against one another on a graph, and those above the line are considered better than average (such as tool-making crows, chatty dolphins and us humans... EQ 7.44).
Which was the smartest dinosaur?
The smartest dinosaur would be a small theropod hunter similar to Velociraptor, with an EQ equivalent to a guinea fowl (0.24-0.34).
Velociraptor was a dinosaur found in central and eastern Asia during the Late Cretaceous Period. It grew to a length of 1.8m and weighed up to 45kg. It was a swift, agile predator of small herbivores, and contrary to its portrayal in Jurassic Park, scientists believe they had feathers.
It also had an unusually large claw on each foot, as well as a special tail that enabled it to balance on one foot while striking and slashing at prey with the other.
The Velociraptor was a dromaeosaurs (small- to medium-sized hunter with large toe claws) and was closely related to the Deinonychus, which was slightly larger and lived in North America in the Early Cretaceous Period.
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Main image credit: Getty Images