The Therizinosaurus was a real dinosaur that roamed Earth, known for its remarkably long claws. Its name, meaning “scythe lizard,” directly references these prominent appendages, which have fascinated scientists since their discovery.
A Real Dinosaur’s Journey
Understanding Therizinosaurus began in 1948 when a Mongolian field expedition unearthed its first fossil remains in the Nemegt Formation of the Gobi Desert. Initial findings were limited, primarily consisting of gigantic manual unguals, or claw bones.
In 1954, Russian paleontologist Evgeny Maleev formally described these remains, initially theorizing they belonged to a large, turtle-like reptile that used its claws to gather seaweed. Therizinosaurus’s identity as a dinosaur, specifically a theropod, emerged through subsequent discoveries in the 1970s and 1980s. More complete fossils of related dinosaurs, such as Alxasaurus and Beipiaosaurus, provided crucial insights into its skeletal structure and evolutionary lineage. These findings confirmed Therizinosaurus’s existence and its place within the diverse dinosaur family tree.
Unraveling Its Unique Features
Therizinosaurus’s exceptionally long claws measured over 50 centimeters (20 inches) and potentially reached nearly a meter (3 feet). These were the longest known manual unguals of any land animal, distinguished by their relatively straight shape with sharp curvatures only at the tips. Despite their formidable appearance, Therizinosaurus was a large bipedal herbivore, a surprising dietary choice for a theropod, a group predominantly known for meat-eating.
This colossal dinosaur reached lengths of 9 to 10 meters (30 to 33 feet) and stood 4 to 5 meters (13 to 16 feet) tall, weighing over 5 tons (11,000 pounds). It possessed a long neck, a relatively small skull, and a horny beak that lacked teeth, suited for processing plant matter. Its robust, pot-bellied body likely accommodated a large digestive system necessary for its herbivorous diet. Evidence from close relatives suggests Therizinosaurus likely had a covering of feathers.
Beyond the Claws: Understanding Its Purpose
The primary function of Therizinosaurus’s impressive claws was not active predation, as their structure suggests they were too delicate for combat. Instead, paleontologists propose these specialized claws were primarily used for foraging, such as grasping and pulling down branches and foliage from tall trees. Its long neck and robust forelimbs facilitated this hook-and-pull feeding mechanism.
Beyond feeding, the claws may have served as a defense mechanism, potentially for intimidation against large predators like Tarbosaurus. While not designed for direct attack, their sheer size could have deterred threats in its Late Cretaceous environment.
The claws might also have played a role in intraspecific interactions, such as territorial disputes or display during mating rituals. Living in lush woodlands and riparian areas, Therizinosaurus occupied a niche as a large browser.