Allosaurus, the "Different Lizard,"
provides a "different" example of an
apex predator than that of the
tyrannosaurus. Contrasting with the
T. rex, the allosaurus measured only
three meters tall, just under twice
the height of a human. It was still
quite long at eight and a half
meters. Its notable skull ridges had
several functions, such as acting as
sun-shades and display items.
Curiously, many skull fossils found
exhibit odd imperfections, providing
valuable research into the paleo-
pathology of dinosaurs and its 
possible effects on creatures.

Living at the top of the food chain,
the menacing claws and jaws of
the allosaurus made it quite the
predator long before the time
of the tyrannosaurus. Abundantly
found in the Morrison Formation, it
absolutely dominated the food chain
by preying upon large herbivores and
possibly even some predators. It
prowled the semiarid environments of
present day America and Portugal
alongside other predators, like
ceratosaurus. Living from the
Kimmeridgian to early Tithonian eras
of the Jurassic, allosaurus had a
delectable selection of prey. It
actively hunted stegosaurus and
members of its family for food and
likely scavenged sauropod carcasses.
It likely only hunted live adult
sauropods in packs, but the social
behavior of these animals is still
up to debate.
