[4] Their most important prey were reported to be the squid Loligo gahi, the siphonophore Sulculeolaria quadrivalvis, and the bony fishes Muggiea atlantica and Coelorhynchus fasciatus.

Other prey options such as octopus or crustaceans would depend on environmental availability, making the dusky catshark a general bentho-demersal predator that eats what fits in its mouth.

However, there is still some data lacking as most Bythaelurus canescens specimens caught are juveniles; adults tend to live at deeper depths of around 1000 meters.

[5] At an active methane seep off the coast of Chile, Bythaelurus canescens was reported to be one of the top predators, with a highly variable diet.

[6] Like many sharks, Bythaelurus canescens reproduces using complex egg capsules which are deposited on the sea floor or attached to rocks and corals.