Big
theropods have "croc"-like brains in so far as they retain the general primitive
shape of archosaurs, rather than the highly derived shape of birds.
However, all theropods studied so far have a bigger brain cavity than would be
expected for a croc of th same body size (that is, a higher EQ (encephalization
quotient) than crocs). Non-avian Maniraptorans and ornithomimosaurs have
far more bird-like brains (in terms of the shape of the brain cavities) than
more primitive forms, and these forms (and tyrannosaurids, actually) seem to
have higher EQs than for more basal taxa.
What
does that mean for intelligence? Well, if you ask 3 ethologists (animal
behaviorists) to define "intelligence" you'll likely get seven different
answers... This is because "intelligence" is not one faculty, but is
instead our name for a collection of different types of brain operations (memory
storage, memory retrieval, spatial relations, problem solving, etc., etc.,
etc.). It is difficult to measure in humans; it is exceedingly difficult
to study in living non-humans. Damned if I can think of an effective
testable way of examining it in fossil taxa, beyond the use of proxies like
brain size and shape.
So, in
any case, dromaeosaur brains were more birdlike than tyrannosaurid or allosaurid
brains, but (like those of Archaeopteryx), not as well-developed as
those in modern birds.
However, the folks at Jurassic Park have never felt constrained
by data when reconstructing the appearance, life habits, and abilities of their
dinosaurs. Back when JP existed only in print the raptors were
already endowed with cheetah speed and trans-chimpanzee intelligence: not quite
faster than a speeding bullet or more powerful than a locomotive, but more
Kryptonian than Terran...
Thomas R. Holtz,
Jr. |