The catshark or lesser spotted dogfish is one of the smallest, thinnest sharks that exists. This shark is benthonic (it lives on the bed) and lives from the most surface areas to depths of 200 m and even 500 m. Its back is brownish with dark stains and the first dorsal fin is closer to the tail than to the head. Their activity is mainly at night, they are carnivores that eat mollusks, small crustaceans and worms, and small pelagic fish and fish from the seabed.
The females form small groups and are joined by the males in spring.
Like all sharks, they have interior fertilization. They are oviparous (96-115 eggs a year). Spawning may occur throughout the year, although it is more frequent between November and July. It lays two eggs at a time in shallow waters, and hatching varies from 5 to 11 months, depending on the water temperature.
Their skin is rough, like all sharks, and was previously used as sandpaper to polish wood. The eggs lie in distinctive capsules, which are known as mermaids’ purses, and are normally found on marine coasts and rocky bays.