Slender smooth-hound variety of benthic fishes and invertebrates, and also scavenges; human garbage has been reported among its stomach contents. Small bony fishes, lanternfishes in particular, are the most important prey type, followed by decapod crustaceans. Cephalopods, gastropods, isopods, brittle stars, dogfish sharks, and cartilaginous fish egg capsules may also be consumed. On the Challenger Plateau, cephalopods are an important food source for juveniles under long. Like the false catshark, the slender smooth-hound exhibits aplacental viviparity with oophagy, in a form different from that in the mackerel sharks. Mature females have a single functional ovary, on the right side, and two functional
Slender smooth-hound numerous unique traits. More recently, he and other taxonomists have increasingly tended to group "Gollum" and "Pseudotriakis" together in the family Pseudotriakidae. This arrangement was corroborated by a 2006 phylogenetic study by Juan Andrés López and colleagues, which found that the two genera have a high degree of genetic similarity across four protein-coding genes and form a natural clade apart from "Proscyllium". An additional species of "Gollum" has now been described, and there is at least one additional species yet to be described. The range of the slender smooth-hound is restricted to the upper and middle continental slope around New