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[Phylum: Chordata] [Class: Chondrichthyes] [Subclass: Elasmobranchii] [Order: Carcharhiniformes]
There are more than 160 species of catsharks. They are small bottom-dwellers that belong to the largest family of sharks (Scyliorhinidae).
Despite being known as dogfish in some regions, the common name 'catshark' comes from the elongated, cat-like eyes and the slender, fusiform body shape.
The worldwide distribution of catsharks means they are found in most temperate and tropical seas, especially:
They live close to the seafloor, often near continental shelves and shelf breaks (slopes) descending deep into the ocean (even 2,000+ metres).
Put another way, most of the catshark species are benthic marine vertebrates that live and hunt along the bottom of the seas and oceans.
However, unlike some members in the shark phylum, catsharks prefer to be around environments where there are rocky reefs, kelp forests, sand, or mud.
They like to hide in crevices or underneath rocks during the daylight. But, they come out during the dark hours to feed on small fish, crustaceans, and various kinds of marine invertebrates.
The general body shape is slender, elongated, and streamlined. The 'fusiform' and flexible build is ideal for bottom-dwelling sharks that like to weave their way through rocks and reefs.
Catsharks have large, ovate eyes (egg-shaped) with vertical slit pupils, like the eyes of a cat. Many also have small triangular nasal flaps located in front of the nostrils and near the mouth.
Even though they have pale coloured skin, most of the catshark species have small tooth-like scales (called dermal denticles) that create a rough texture.
Here's the thing:
The beautiful patterns in cat sharks include spots, stripes, or chain-like features that create superb camouflage for animals that live in deep, dark water close to the seabed.
Compared with other types of sharks, all catsharks are small. The pygmy ribbontail catshark is one of the smallest, growing to about 24 centimetres long (a little over 9 inches).
By comparison, one of the biggest catsharks is the nursehound - which can be 160 centimetres long (more than 5 feet in total body length).
Interesting Fact: If you're wondering... What animal kills the most humans in the world, it's definitely not any of the catshark species. On the contrary, their role as mid-level predators is invaluable in marine ecosystems.
Having rested during the day, these nocturnal carnivorous hunters become much more active at night. They prowl close to the ocean floor, using their electroreceptors and keen sense of smell to detect their favourite prey hidden in sediment, such as:
Fun Fact: Some species of catshark are biofluorescent, meaning they glow in the dark (e.g., Scyliorhinus retifer). Scientists believe this might help them identify other cat sharks while hunting in dimly lit environments.
More than one hundred species of deepwater catshark belong to the family Pentanchidae, and nearly all of them are still in existence today.
This section contains some lesser-known facts about deepwater catsharks, including where they live, what they eat, and how these elusive deep-sea creatures reproduce.
Members of the family Scyliorhinidae are mostly oviparous, meaning the females lay eggs inside robust egg cases (called a mermaid's purse).
It takes almost twelve months for a baby catshark to hatch from an egg. As a consequence, it's not uncommon for some females to hold onto the eggs until they are close to hatching.
The cat sharks that exhibit ovoviviparity, (otherwise known as aplacental viviparous), hold onto the embryos until they are completely developed and then give birth to live sharks.
Predation in catsharks comes from some of the largest sharks, especially the sand tiger shark (ground sharks) and the broadnose sevengill shark (cow sharks).
That being said, other significant threats come from bycatch, ocean pollution, habitat degradation, and commercial and recreational fisheries.
Important: The IUCN Red List of Threatened Species shows that the conservation status of many catsharks is of "Least Concern" (LC). However, in 2017 they listed the speckled catshark (Halaelurus boesemani) as "Vulnerable" with a "Decreasing" population trend.