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Who were the Therizinosaurs?

They were gigantic, as big as a Tyrannosaurus Rex. They had huge sharp claws, as long as the “grim reaper’s sythe,” as Dr. Thomas Holtz likes to say. They had bulky bodies, but their heads were small, with leaf-shaped teeth. They belonged to the group called theropods, which are usually the carnivores of the Mesozoic. But these dinosaurs were herbivores. In their ancestry, they switched from eating meat to mostly eating plants, with possibly occasional small bits of meat protein. They lived during the Cretaceous period in North America and Asia.

These were the Therizinosaurs.

Therizinosaurs had backward facing pubic bones, unlike most theropods. This happened over time as they switched from carnivore to herbivore because it was necessary to make room for their huge guts, which were needed to digest their plant-based diet. Their guts were so large they appeared to have “beer bellies.” They could not move quick, because of this bulk, but if predators threatened, they might find themselves at the sharp end of those long claws.

Therizinosaurs are among the weirdest of the ever-fascinating and marvelous group of animals we call dinosaurs!


Learn more about the Therizinosaurs and other dinosaurs in Susan’s latest book, Dinosaur Seasons, 2nd edition.


Susan is a retired psychologist/administrator that is most proud of her son and two granddaughters. She has many interests, including paleontology and history, and started writing early in her life. Susan wrote her first book when she was ten years old about horses. Now that Susan is retired, she plans to focus more on writing. Check out Susan Verzulli POP author page here on Facebook and Instagram.