Therizinosaur

a drawn rendition of a ground sloth and a computer generated image of a therizinosaur running
Like giant ground sloths (left), therizinosaurs (right) were probably slow moving and used their long reach and claws to shear off leaves from high branches.
Therizinosaur is Greek for “reaping lizard”. This family of theropod dinosaurs had a very unusual set of characteristics including long necks, small heads, potbellies, feathers, and gangly front limbs with long claws.

Identification level: Genus
Numerous species of therizinosaur existed during the Late Cretaceous. Denali's therizinosaur track has been attributed to the ichnogenus (meaning a genus known from trace fossils alone, like footprints)Saurexallopus.

What is for dinner?
Therizinosaurs are theropods, most of which are bipedal meat eaters. Their long claws leads one to imagine that therizinosaurs could slice and dice any animal they pleased. Don’t be fooled, though – based on tooth, jaw and abdominal characteristics, therizinosaurs are believed to have been vegetarians.
 
a four toed track in rock

NPS photo

What is for dinner?
Therizinosaurs are theropods, most of which are bipedal meat eaters. Their long claws leads one to imagine that therizinosaurs could slice and dice any animal they pleased. Don’t be fooled, though – based on tooth, jaw and abdominal characteristics, therizinosaurs are believed to have been vegetarians.

How do we know I lived in Denali?
To date a handful of therizinosaur hind foot tracks with four distinct toe impressions have been found in Denali. This is the northernmost known occurrence of the dinosaur group Therizinosauria, and its presence in Denali supports the theory that dinosaurs wandered between Asia and North America during the Cretaceous.

Fun Fact
The first evidence of the therizinosaurs living in Alaska was a single footprint found by a park educator in 2010. Since then several additional tracks have been found.
 
a size comparison that shows that a therizinosaur is taller than an average human
How do I size up? - The therizinosaurs in Denali were similar in size to an adult man, but they would sure look strange to us if we saw one hiking a trail in the park!

Last updated: August 15, 2016

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