I'm starting a tradition today I hope I can keep up. Every Friday I'm going to try to add some educational value to this LJ (and exercise my obsessive nerdiness) by putting up some info about a different shark. This is inspired by the myriad weekly offerings at different blogs and sites I read, notably Pharyngula (
Friday Cephalopod), Deep Sea News (
TGIF), and Ectoplasmosis (
Chtulhu Cthursday). Plus it's a somewhat practical use of my
Sharks of the World book (simultaneously the best and worst possible Christmas gift someone could get for a person like me - unless of course you count the
Cthulhu iPod cozy). So the following info is either from there or from the swirling mass of shark information trapped in my brain that's only gotten larger and stronger since I was a kid.
Fishbase may come in too.
And with that link-splattered introduction out of the way, allow me to introduce
Mustelus canis, the Smooth Dogfish.

Also referred to as the dusky smoothhound,
M. canis is actually not a true dogfish at all (family
Squalidae) due to the presense of an anal fin and a lack of spines on its dorsal fins. It actually falls under the family
Triakidae, which it shares with the other species of smoothhound, the gummy sharks (basically Australian Smoothhounds), the soupfin shark, and the leopard shark.
Mustelus canis is readily identified by the small barbels around its nostrils, large eyes, deeply notched tail, and dark grey dorsal coloration (though young specimens are lighter colored and usually have dark fin margins). It's a small to mid-size coastal shark that can reach up to 1.5 m (about 3 or 4 feet) and lives on the Atlantic continental shelf along the East coasts of North and South America. Generally preferring temperate waters, it is absent from the tropics with the exception of a subspecies in the Caribbean (
Mustelus canis insularis).
Though it has been found in waters up to 360m deep, this shark usually sticks to shallow, inshore sand and mud bottoms. It's a common site at beaches and is frequently caught by surf-casters looking for bluefish and striped bass. Smooth dogfish usually feed on small prey such as squid, small bony fish, and crabs, and with their small, rasping teeth they probably couldn't do much damage to anything larger than them. They are a very social shark, traveling in loose packs and occasionally schooling with other similar-sized species of sharks.
I've had a lot of personal experiences with this species, since it is the shark that comes up most often on the Rhode Island DEM's trawl surveys. They are hardy in captivity and adapt readily to aquarium life (as long as they're well-fed they will behave and keep from eating any smaller fish they share a tank with).
M. canis is a very active, inquisitive shark and can be conditioned to take food by hand (I used to regularly hand-feed small ones during my time at the DEM).
The shark most often associated with
Mustelus canis is the spiny dogfish (
Squalus acanthias), which is the origin of the smooth dogfish's common name in American waters. Smooths and spinys occasionally school up together and can often be found competing for the same food sources. The range and preferred habitat of the smooth dogfish also coincides with that of the similar-sized Atlantic sharpnose shark (
Rhizoprionodon terraenovae) and the slightly larger sandbar shark (
Carcharinus plumbeus) which take larger prey and may competitively dominate it, but don't seem to prey directly on the species. However,
M. canis has been confirmed to be a prey item for some of the large coastal sharks, including the bull shark (
Carcharinus leucas), tiger shark (
Galeocerdo cuvier), sand tiger (
Carcharias taurus) and great hammerhead (
Sphyrna mokarran, a specialist at eating other sharks). A few specimens have been found in the belly of the great white shark (
Carcharodon carcharias).
Final thought on this species: I want one as a pet.