Duonychus tsogtbaatari: The Giant Two-Clawed Dinosaur of Mongolia – Used for Skinning or Tearing Meat?

In April 2025, paleontologists published in the journal Nature a new species of therizinosaurid named Duonychus tsogtbaatari (named in honor of the Mongolian paleontologist Tsogtbaatar). The fossil was unearthed from the Bayanshiree Formation (Late Cretaceous, approximately 85–90 million years ago) in the Gobi Desert, Mongolia.

The most distinctive feature of Duonychus is that it only has two enormous claws on each hand (instead of three like most other therizinosaurs). The second claw is extremely large and strongly curved, nearly 30 cm long when alive, forming an impressive “pair of scissors.” This is a rare case in the therizinosaur group.

What was the function of the two enormous claws?

Researchers (led by Yosнιтsugu Kobayashi and Darla Zelenitsky) conducted a thorough analysis and concluded:

• The claws were primarily used for stripping foliage and pulling branches. Their strongly curved structure, smooth surface, and immense grip were well-suited for pulling leaves, stripping bark, or breaking branches to eat plants—consistent with the predominantly plant-based diet of the therizinosaur group.
• They were not used for tearing flesh like carnivorous theropods. There was no evidence of sharp teeth or powerful jaws specifically for hunting. The claws were too large and curved to be used as active weapons.
• They may have played a secondary role in display or defense, but the most widely supported primary function today is foraging (finding plant food).

This finding demonstrates the high morphological diversity of claws in therizinosaurs, and Duonychus represents a branch that developed specialized “claws” for exploiting plants in its own way.

As of June 2026, Duonychus tsogtbaatari remains one of the most noteworthy dinosaur discoveries of 2025. It further confirms Mongolia as a “paradise” for exotic therizinosaurs — where these “giant scissors” were used primarily for skinning and pulling leaves, rather than tearing apart enemies.