Invertebrates
Chilean Stag Beetle
Chiasognathus grantii · also called Darwin's beetle
Wielding mandibles longer than his own body, a male Chilean stag beetle battles rivals for access to females, a spectacular species first collected and described to science by Charles Darwin himself during the voyage of the Beagle.
Overview
The Chilean stag beetle, Chiasognathus grantii, is a Least Concern invertebrate native to forest habitat across southern Chile and Argentina. Its extraordinarily oversized male mandibles, its ritualised combat behaviour, and its historic connection to Charles Darwin make it one of the more visually striking and scientifically notable beetles found anywhere in South America.
Weapons built for show, not slaughter
Despite carrying mandibles longer than their own bodies, male Chilean stag beetles rarely cause serious harm to one another, their oversized weapons serving more as ritualised tools of contest than instruments of real combat.
Status
Least Concern, remaining widespread and generally stable across suitable temperate forest habitat in southern Chile and Argentina.
Chilean Stag Beetle: common questions
Why does the Chilean stag beetle have such large mandibles?
Males of this species carry enormous mandibles that can exceed the length of their own body, used in ritualised combat with rival males competing for access to females.
Why is it also called Darwin's beetle?
This species was first collected and described to science by Charles Darwin during the voyage of the Beagle, giving it one of its alternative common names.
Do female Chilean stag beetles have large mandibles too?
No, females of this species have much smaller, less exaggerated mandibles than males, since they do not participate in the same combat behaviour over mates.
What does the Chilean stag beetle look like?
This species has a distinctive metallic greenish-bronze colouration across its body, giving it a striking appearance in direct sunlight.