Based on morphological similarities, Ginglymostoma is believed to be the sister genus of Nebrius, with both being placed in a clade that also include species Pseudoginglymostoma brevicaudatum, Rhincodon typus, and Stegostoma fasciatum.
Newly born nurse sharks have a spotted coloration which fades with age and are about 30 cm in length when nascent.
[2] In the Western Atlantic, including the Caribbean, it ranges from Rhode Island to southern Brazil,[10] and in the East Pacific from Baja California to Peru.
Juveniles are mostly found on the bottom of shallow coral reefs, seagrass flats, and around mangrove islands, whereas older individuals typically reside in and around deeper reefs and rocky areas, where they tend to seek shelter in crevices and under ledges during the day and leave their shelter at night to feed on the seabed in shallower areas.
[12] Nurse sharks are opportunistic predators that feed primarily on small fish (e.g. stingrays) and some invertebrates (e.g. crustaceans, molluscs, tunicates).
[11] They are typically solitary nocturnal animals, rifling through bottom sediments in search of food at night, but are often gregarious during the day forming large sedentary groups.
The mating cycle of nurse sharks is biennial, with females taking up to 18 months to produce a new batch of eggs.
The mating season runs from late June to the end of July, with a gestation period of six months and a typical litter of 21–29 pups.