Dusky smooth-hound time to induce tonic immobility in smooth dogfish was 32.5 seconds. The mean duration of the tonic immobility was 61.9 seconds. Sharks that had the “limp” response also exhibited tonic immobility. The “limp” response is a criterion for the onset of tonic immobility. Dusky smooth-hound The dusky smooth-hound ("Mustelus canis"), also called the smooth dogfish or the dog shark, is a species of houndshark in the family Triakidae. This shark is an olive grey or brown in color, and may have shades of yellow or grayish white. Females live to 16 years and males have a lifespan of 10 years.
Dusky smooth-hound the lower is smaller and rounder and the upper has a deep notch. They do not have any fin spines, unlike the spiny dogfish. They have a tapering, blunt snout. They can be gray to brown and their undersides can be white to yellowish gray. Smooth dogfish have the ability to change colors using melanophores to help them camouflage. Newborns have lighter gray edges on their fins and have tail fins edged in white. On average, smooth dogfish are about 48 in long, but can reach up to 5 ft. They have an inter-dorsal ridge. One main characteristic of elasmobranch