The asteroid that hit the Earth 66 million years ago wiped out all life of the period, represented mostly by dinosaurs. If they never went extinct, what would they look like today? A recent article in The Conversation magazine tries to find the answer.
In the 1980s, paleontologist Dale Russell proposed a thought experiment in which a carnivorous dinosaur evolved and used intelligent tools. This “dinosauroid” had a large brain with opposable thumbs and walked upright, much like early humans.
It’s not an impossible scenario, but an unlikely one.
This because an animal’s biology constrains the direction of its evolution. Carnivorous dinosaurs, in fact, evolved to get bigger and bigger – and to be able to dominate their environment – by sacrificing the size of the gray matter. These creatures have shown a weak tendency to increase in size of the brain over time.
Despite its size, the T. rex brain (perhaps larger than expected) weighed only 400 grams, while that of a Velociraptor 15 grams. For comparison, you should know that the average human brain weighs 1.3 kilograms. Probably if they were still alive today, there would still be long-necked supergiant herbivores and huge tyrannosaur-like predators.
They may have developed slightly larger brains, but there is little evidence available for a human-like evolution scenario. Today some descendants of dinosaurs – birds such as crows and parrots – have complex brains, can use tools, speak and count… but they are the mammals such as monkeys, elephants and dolphins to have developed bigger brains and more complex behaviors.
