Allosaurus Fact Sheet

Common Name:

Allosaurus fragilis

Scientific Name:

Fagile different lizard

Wild Status:

Jurassic Period, 155-150 MYA


North America, Portugal


Countries in North America and Portugal



Life Span:



30 feet long, 8 feet tall at the hips, 1.5 tons

Cool Facts:

  • Surprisingly for a large predator, Allosaurus had a relatively weak bite for its size. It most likely attacked prey by inflicting slashing-style injuries with its serrated teeth and then waiting for the animal to succumb to its wounds.
  • Several Allosaurus specimens bear puncture wounds indicative of being struck by the thagomizer of a Stegosaurus and there are stegosaur plates with U-shaped pieces missing that match up with an allosaur snout, providing clear evidence of a violent predator-prey relationship between the two species.


Allosaurus is often referred to as “the lion of the Jurassic” and was one of the most common carnivores of its day. There is considerable debate as to whether or not Allosaurus lived in packs. It is not uncommon to find fossil deposits containing multiple individuals, and some paleontologists cite bite marks on snouts as evidence for establishing hierarchy within a social group. However, others argue that this is evidence for intraspecific competition rather than sociality.

Taxonomic Breakdown:

Kingdom - Animalia Phylum - Chordata Class - Reptilia Order - Saurischia Family - Allosauridae Genus - Allosaurus Species - A. fragilis

Conservation & Helping:

The Allosaurus is currently extinct, and was believed to exist 155 - 150 Million Years Ago

For Teachers and Educators


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