Hexarthrius mandibularis is one of the world's largest stag beetle.

[2] This beetle has a dull, dark, brick reddish body.

These have small teeth running down the inside edge, with one large, forward-pointing pair located approximately a third of the way down from the tips.

During the larval stage, Hexarthrius mandibularis lives in rotten hardwood, feeding on it.

Later, during the imago stage, it consumes tree juice.