Turtle-like scythe lizard
Cretaceous Period, 100-70 MYA
33 feet long, 10 feet tall at the hips, 5 tons
- It was first believed that Therizinosaurus was a predator like other theropods, using its enormous claws to reach in between the ribs and into the abdominal cavity of potential prey. However, the claws lack a cutting edge and the angle of curvature is too gentle to allow it to effectively grip a struggling animal. Instead, these claws were used as pruning hooks to help bring food within reach. Standing on two legs, Therizinosaurus could feed at a height above that of competing herbivores. Their lifestyle was in many ways similar to that of the giant ground sloths that appeared in the Cenozoic.
- While no feathers have been discovered associated with Therizinosaurus specifically, a number of its relatives have been found covered in down. This plumage would have been used to help keep the animal warm, suggesting a warm-blooded metabolism, and possibly for display.
Therizinosaurus had the largest claws of any known animal, measuring just under a yard in length. When first discovered, paleontologists mistook the claw for the rib of a giant turtle, leading to the species name “cheloniformis”. Therizinosaurus and its relatives are unusual in that they are a group of theropods that have switched from carnivory to herbivory. Much of their anatomy reflects this dietary strategy. An exceptionally wide pelvis would have housed the extensive guts a herbivore needs, and unlike the feet of other theropods, Therizinosaurus had four toes touching the ground to help support the extra weight. Their heads were small, tipped in a keratinous beak, and full of close-packed, serrated teeth ideal for slicing vegetation.
Kingdom - Animalia Phylum - Chordata Class - Reptilia Order - Saurischia Family - Therizinosauridae Genus - Therizinosaurus Species - T. cheloniformis