Males use their jaws in combat: they hook them under the opposite beetle's wings, pull up and throw their opponent to the ground (from 20 meters above, as they are in great trees most of the time).

[5] Charles Darwin collected the species in Chile during the second voyage of HMS Beagle, and, despite the enlarged mandibles of the males, he noted that the jaws were "not so strong as to produce pain to finger".

C. grantii is also known locally as ciervo volante, cantaria, and cacho de cabra in Spanish and llico-llico in the Mapuche language.

[3] Synonyms of this species include:[9] Chiasognathus grantii is very variable in size and in the development of the jaws and exhibits a strong sexual dimorphism.

The thorax is broad and the anterior and posterior margins are densely ciliated with short pale hairs.