[2] D. neptunus is 12 to 15.5 cm (4.7 to 6.1 inches) long[3] with a black body.

Sexual dimorphism is present in the species; for example, males having large ''horns'' on their heads and are much smoother than females.

This species is similar to the hercules beetle but is larger and has slender, curved horns.

[2] This species lives in the northwestern regions of South America in the countries of Colombia, Peru, Ecuador, and Venezuela.

[4] Larvae feed on decaying, rotten wood and adults will eat fruit.