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
Dusky smooth-hound and "canis" translates to dog. "M. canis" has an allopatric relationship with "M. mustelus" (common smooth-hound) and a sympatric relationship with "M. norrisi" (narrowfin smooth-hound). "M. canis" is found in marine and brackish waters and is demersal (bottom-dwelling) and oceanodromous (migratory in seas). They can be found between 42°N and 44°S and 100 and 46° W. "M. canis" in the North Atlantic migrates in response to changing temperature. In winter, they can be found in the Carolinas to the outlet of the Chesapeake Bay, and in summer from the mid-Atlantic to southern New England. They are most abundant on the