[1][2] Later records, such as those from the Miocene assigned to the species S. subulatus, are highly dubious and may be misidentified sand sharks.

Scapanorhynchus had an elongated, albeit flattened snout and sharp awl-shaped teeth ideal for seizing fish, or tearing chunks of flesh from its prey.

Unlike modern goblin sharks, which inhabit deep ocean waters and are sluggish opportunistic feeders that feed on benthic fish and invertebrates, Scapanorhynchus appears to have been a pelagic apex predator that inhabited the epipelagic zone or continental shelf.

[2] An isotopic analysis of its teeth suggests that it largely preyed on fish and occupied a high trophic level in its ecosystem.

It appears to have occupied a similar trophic level to Squalicorax, another marine lamniform of the same habitat.