- Order: Saurischia
- Suborder: Wyvern Feet
- Family: Rex
Tigrex preys heavily on large herbivorous animals such as Popo and Aptonoth. Can most likely bring down lesser wyvern species. Capable of thinning out large herds of animals as stressed by the village chief of Pokke village. In frozen environments it is rivaled by Abiorugu,the rare Rajang, the rare Doragyurosu, Khezu , Kushala Daora, Barioth, Brachydios, Glacial Agnaktor, and Zamtrios. But they all could deal heavy wounds on each other. Tigrex is among the fiercest wyverns sighted in the deserts, only rivaled in speed and strength by the herbivorous but highly territorial Diablos, its one-horned relative, the Monoblos, predatory Elder Dragons and Hyujikiki of the Old World along with the Sand Barioth, Nibelsnarf, and its relative Brute Tigrex of the New World.
Grimclaw Tigrex have many of the same adaptations as Tigrex, however, there are a few differences between them. Due to blood vessels passing through its skin, certain parts of its body has changed to a blue color. These parts include Grimclaw Tigrex's head, tail, wings, and claws. The blood vessels have severely helped its claws develop irregularly, making them harder and more savage, while also pulsing through its shell. From it having these irregular claws, Grimclaw Tigrex is able to use its claws more often while attacking. This allows it to destroy the ground in a destructive fashion or even throw massive snowballs. Like normal Tigrex, Grimclaw Tigrex has a powerful roar that can be compared to a Brute Tigrex or even Molten Tigrex.
Grimclaw Tigrex is a lot more hostile than a normal Tigrex.