Nurse sharks are found in the warm, shallow waters of the western Atlantic and eastern Pacific oceans. They are often observed at depths of a meter or less within the intertidal zone, though they are known to range down to depths of at least 12 meters. The nurse shark is often found along reef sites, within mangrove channels, and on sand or seagrass flats. We see these on many dives from Vero Beach to Lauderdale by the Sea and even off Fort Zachary in Key West. The love hiding under ledges and in some of the artificial reef pileons. Nurse sharks show a strong preference for resting sites, and repeatedly return to the same places after nocturnal activity. In many of our favorite shore dive sites, locals have named them. The Sea Emperor wreck off of this same coastline usually has a group of Nurses sleeping under the bow.
Nurse sharks have yolk sacks which mainly sustain the intrauterine development of the young. Aplacental viviparity (which used to be called ovoviviparity) is when animals hatch from eggs, but the eggs hatch and the babies develop inside the female’s body. There is no placenta to nourish the pups. In the coastal waters of Florida, birthing typically occurs in late spring and early summer months. They will have 21-28 young pups.
Nurse sharks are nocturnal feeders and love tiny reef fish, crabs, lobster, urchins, and shrimp. The nurse shark has small mouth, but its large, bellows-like pharynx allows it to suck in food items at high speed. This system allows the species to prey on small fish that are resting at on the sea floor and in caves at night. They use their strong jaws to crush and eat shellfish and even coral, but prefer to dine on fish, shrimp, and squid. Nurse sharks have been known to feed on large, heavy shelled conchs by flipping the shell over, exposing the vulnerable apeture. Using their teeth and suction,then extracting the snail in one piece. Yummy!
Description: Most of the ones I have seen are grey and white. They can be brown or deep rust color. It has a very small, underslung mouth, and is the only shark with barbels at the nostrils. The mouth is set forward of eyes and is relatively high up on the head – maintaining a more forward position. Nurse sharks have respiratory systems that can pump water over their gill slits. This allows them to breathe without moving. Look at the nurse shark’s fins. Instead of the pointy dorsal fins that we might see in movies when sharks swim near their prey, nurse sharks have rounded dorsal fins on their back, the first one bigger than the second. Nurse sharks have extremely long caudal fins(tails) which make up more than 25% of their total body length. The bottom fin, the pectoral fin, helps the nurse shark to hover, and sometimes even to “walk” along the ocean floor. This hovering motion sometimes proves useful to nurse sharks looking for a bite to eat.
Size: Most seen in shallow water are from 5 to 50 pounds, but they can grow quite large in deeper water. World record 210 pounds. However, they can be huge—up to 14 feet (4.3 meters)—and have very strong jaws filled with thousands of tiny, serrated teeth, and will bite defensively if stepped on or bothered by divers who assume they’re docile. They can weigh up to 150 kg (330 lbs). They are usually more docile than other shark species but if you irritate one they will bite to protect themselves. I am an idiot! I thought these would not hurt you. Learned something new today. They live up to 25 years and you can find them resting on the sea floor during the day. They are nocturnal animals that feed at night.
- Other facts:
This shark can taste with its skin! Also their sluggish, docile nature coupled with their proximity to humans may be starting to stress their population. They are not commercially fished, however, they are hunted for their extreamely tough, leathery skin.
They use their strong jaws to crush and eat shellfish and even coral, but prefer to dine on fish, shrimp, and squid. They are gray-brown and have distinctive tail fins that can be up to one-fourth their total length. Unlike most other sharks, nurses are smooth to the touch.