The Nurse Shark, also known as the Ginglymostoma cirratum, gets its name from Greek Roots. It may come from the strange sucking sounds they make when searching for prey in the sand. As with all sharks, this giant fish is incredibly interesting and very important to the delicate marine ecosystem, especially near fragile coral reefs.
They can get quite large with a length of up to 4.5 meters (15ft) as adults. These large creatures reach weights as high as 150 kilograms (330 pounds). Typically, they live to between 25 and 35 years of age.
While most fish, including sharks, must keep moving in order to breath, Nurse Sharks can remain motionless while resting on the sea floor by facing against the flow of water and pumping the water through their mouths and gills.
As a bottom dweller, they spend much of their time on the sea floor in tropical waters around coastal shelves, reefs, and channels. They seem to enjoy the Atlantic and Pacific Oceans, especially around the Caribbean Islands. This is generally a shallow water fish.
During daylight hours, they are seen in groups as large as 40. While in these groups, they mostly remain hidden under submerged ledges and around reefs. Scientists believe they stay in these groups for protection purposes only with very little dominance or hierarchy.
At night, they become more active, but also more solitary, wandering the waters alone.
Being bottom dwellers with small mouths, they are unable to consume large fish. They hunt alone and catch their prey from the sea floor, mostly by sucking their prey into their mouths. While doing this, a Nurse Shark will inevitably make an unmistakable “slurping” or sucking sound, completely unique to this species.
The preferred prey includes sea snails, crustaceans, mollusks, and other small fish. In addition, they have been seen grazing for algae and ground corals.
This shark species is Viviparous, meaning eggs develop within the uterus of a female until birth. The pregnancy period usually lasts about 6 months with births occurring generally in the months of June and July. After birth, an adult female Nurse Shark is unable to produce eggs for 18 months.
In average, 30 pups are born at a time. Cannibalism between pups does occur, with the larger and stronger pups eating the underdeveloped ones.
When pups are born they are only about 30cm long (12in) and have a spotted colored skin. As with Tiger Sharks, they lose the spotted patterns with age.
This species is not typically hunted by commercial fishers or for sport fishing. However, some small operations capture this fish for its skin, which is used in high quality leathers. Their liver is also harvested for certain types of oils. Due to their relatively slow speeds, they are very easy to catch.
The threat to humans is very minimal. There have only been a few attacks ever recorded, and only one of those attacks was unprovoked. No fatal attacks have ever been recorded.