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.
Humpback smooth-hound 45°S. Its depth range is between but it is most common between . It is found near the seabed, often on rocky shores, where it feeds on small fish and crustaceans such as crabs and mantis shrimps. It is viviparous and the females bear litters of five to ten young which are about long when born. The humpback smooth-hound is fished for human consumption in Chile but more particularly in Peru, where it is more common. Along with the spotted houndshark ("Triakis maculata") and the speckled smooth-hound ("Mustelus mento") it is known as "tollo" in its local fisheries, and of