These sharks are characteristically large and sluggish. When they are born, they measure 11 to 12 inches. At full growth though, their length varies from 2 to 13 feet. The largest of this species are about 14-feet long. They generally weigh about 110 kg.
Nurse sharks attain maturity at 15 to 20 years and mate during the summer. Their reproduction is termed 'ovoviviparous', wherein the embryo does not receive any nutrition from the placenta. The gestation period is around six months.
Each female has a maximum of only two live young ones, as the firstborns try to eat their siblings in the uterus, leaving only one in each of the two fallopian tubes.
Nurse sharks have barbells, which are thin, fleshy, whisker-like organs on their lower jaw (in front of the nostrils) that they use to locate their food. They eat octopus, mollusks, sea urchins, squids, spiny lobsters, shrimp, stingrays, puffers, and crabs.
They are also known to feed on shelled conchs―a seemingly impossible feat these sharks achieve by flipping them over and sucking the snail out. They have thousands of replaceable teeth, which are serrated and fan-shaped; these play a crucial role in their diverse diet.
Nurse sharks are threatened by predators like tiger sharks and lemon sharks. Great hammerhead sharks and bull sharks are also known to attack them, though the instances are rare.
Additionally, nurse sharks are hunted by humans for their meat, skin (which makes good quality leather), and liver oil. At the ongoing rate, we are set to lose them sooner or later, and that will have drastic effects on the food chain and consequently, the marine environment.