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nurse shark

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"The nurse shark's skin is smoother than most sharks. It feels like sandpaper."

Sometimes called the couch potatoes of the sea, nurse sharks are large, quiet fish that drift slowly along the ocean floor in shallow water, sucking up food as they go. They hunt alone at night, but return to comfortable resting places during the day to doze off in groups. Despite their habitat close to humans, these fish are rarely harmful; they only bite when frightened or provoked. These mild-mannered sharks are quite at home in zoo aquariums and can live up to 25 years in captivity.

nurse shark 1

© AZ-Animals.com

5 Nurse Shark Facts

  • Unlike many other shark species that must swim all the time to breathe, nurse sharks use buccal suction breathing . They use their oral muscles to draw water into their mouths to oxygenate their gills, keeping them still and even sleeping.
  • These sharks pose no threat to humans unless disturbed. In fact, many people swim around these sharks without knowing they are there.
  • When a school of nurse sharks finds a comfortable resting place, they return there after hunting each day, rather than migrating like many other fish species.
  • They "walk" across the ocean floor with their pectoral fins, which females sometimes bury in the sand to avoid courtship by males.
  • Instead of chasing prey with a series of gnashing teeth like other sharks, this shark swims above the sea floor, sucking up food like a vacuum cleaner . After sucking food into their mouths, they use their rows of serrated teeth to crush it up before swallowing.

Read more incredible nurse shark facts here.

scientific name

nurse shark
Nurse Shark (Ginglymostoma cirratum)

©Gary Rinaldi/Creative Commons

Nurse sharks belong to the family Ginglymostomatidae and the class Chondrichthyes . Its scientific name , Ginglymostoma cirratum , is a mixture of Greek and Latin and means "curly hinged mouth." The name is apt, as this shark always seems to be frowning. Because this shark likes to stay close to the bottom of the ocean, many scientists believe its name comes from the Old English word "hurse," which means bottom shark.



species evolution

Nurse Shark Teeth - Nurse Shark
Nurse sharks are thought to have evolved from a group of spiny fish called echinoderms.

©frantisekhojdysz/Shutterstock.com

All sharks are believed to have evolved from the Acanthodian, a group of spiny fish that first appeared during the Paleozoic Era some 400 million years ago. This group of fish then became the two main groups of fish we have today—cartilaginous fishes ( Chondrichthyes ), of which sharks were a part, and bony fishes ( Osteichthyes ), which included salmon.

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type

In addition to the Atlantic nurse shark, this shark includes two other species and should not be confused with the gray nurse shark, which is another species of shark ( Carcharias taurus ). The Nurse Shark consists of the following parts:

  • Tawny Nurse Shark ( Nebrius f errugineus )
  • Short-tailed nurse shark ( Pseudoginglymostoma brevicaudatum )

appearance

Nurse Shark Teeth - Nurse Shark
With their broad bodies and short snouts, the nurse shark looks different from its more dangerous relatives,

© tali de pablos/Shutterstock.com

Nurse sharks have a broad body with a short snout and a small, rectangular mouth. They have two sensory organs, called vibrissae, that grow downward from the upper lip. These tentacles help them find small fish and crabs hiding in the sand.

This shark looks a bit different than many of its more dangerous relatives. Their thick skin is smoother than that of most other sharks, and their dorsal fins are rounded rather than the usual sharp ones usually associated with other species. Their color also sets them apart – they are tawny rather than grey.

These sharks grow to be about 7.5 to 9 feet long and weigh between 150 and 300 pounds. The largest nurse shark ever recorded was 14 feet long, more than twice the height of an average human. Unlike more dangerous shark species, their dorsal fins are rounded rather than pointed. They also have long tails, making up about a quarter of their total length.

Behavior

The nurse shark is a solitary nocturnal hunter, but if you see it during the day, it's likely to be resting among a group of other similarly sized sharks. These sharks do not migrate; when they finish their night hunt, they return to their favorite caves or reefs to rest.

Habitat

nurse shark
Nurse sharks prefer warm, shallow water and live close to human activity.

© Dr. Mathew Gilligan – Public Domain, NOAA

Nurse sharks prefer warm, shallow water and can be found in the eastern Pacific and western Atlantic. They live close to human activity, and while they are generally non-aggressive, they will bite in self-defense if humans encroach on their territory.

population

Worldwide populations of nurse sharks were estimated by distance sampling analysis and their current numbers are believed to be between 3,858 and 14,375, although their numbers have declined in some areas due to previous overfishing for their skin and oil . Since humans are no longer hunting these sharks as often, the species as a whole is thriving, and depending on location, their populations may be classified as vulnerable or of least concern.

diet

Collection of nurse sharks
Nurse sharks (Ginglymostoma cirratum) gather at Highborne Cay, Bahamas

© Kim/Creative Commons

Nurse sharks have a row of tiny serrated teeth in their mouths for crushing hard-shelled crustaceans and snails. Small fish, shellfish, shrimp and squid are the nurse shark's favorite food, though they also sometimes eat algae and coral. As they hunt at night, they are believed to eat resting fish, which makes the fish slow and easy prey.

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For a complete list of nurse shark prey, see our "What Nurse Sharks Eat" article, which provides an in-depth look at their diet.

Predators and Threats

The nurse shark doesn't get hunted very often by any particular predator, but it can provide easy food for larger fish like tiger or lemon sharks. This shark is not a threatened or endangered species.

Reproduction, Babies and Longevity

baby nurse shark
Baby nurse sharks are about 8 to 12 inches long at birth.

©George P Gross/Shutterstock.com

When a nurse shark wants to mate, the male bites the female's pectoral fins to hold her in place during copulation. Research has shown that the species' reproductive process is unique compared to other sharks in that more than one male can fertilize the same litter.

This shark is oviparous, which means the female carries the fertilized eggs inside her for hatching. When the 6-month incubation period was over, she gave birth to a litter of about 25 live pups. These pups are about 8-12 inches long at birth. After giving birth, females take 18 months to lay eggs and go through the reproductive cycle again.

in the zoo

Nurse sharks do well in captivity, possibly because they are less active than other shark species. Since they don't need to swim all the time to breathe, they are less bothered by smaller living spaces than their more active cousins. Nurse sharks in captivity can live an average of 25 years.

You can find them at the Point Defiance Zoo and Aquarium in Tacoma, Washington; the Omaha Henry Doorly Zoo and Aquarium in Omaha, Nebraska; and the National Aquarium in Baltimore, Maryland, among others.

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about the author


I was born in New York, got my journalism degree from Boston University, took a detour to San Diego, and am now back in New York. I love traveling with my husband, but always miss my favorite little Peanuts, half Chihuahua/half Jack Russell, all the trouble. We are certified to dive so one day we can dive with great white sharks and I hope I can swim with orcas too. If my house fits it, I'll add a pig – or a sloth.

Nurse Shark FAQs (Frequently Asked Questions)

Is it safe to swim with nurse sharks?

Swimming with nurse sharks is relatively safe, but that doesn't mean it's completely risk-free. Although these slow-moving sharks are docile, you must remember that they are still wild animals and may attack if they feel threatened.

Can I pet a nurse shark?

These sharks are generally harmless to humans, but that doesn't mean you should try petting them. Their mouths are small, but they protect themselves with sharp serrated teeth if you startle them or step on them.

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Have nurse sharks ever killed people?

While their teeth are sharp and can inflict some damage, there are no recorded reports of nurse shark attacks resulting in human fatalities. Most of these sharks are docile and will only bite when provoked.

Are Nurse Sharks Carnivores?

Yes, nurse sharks are carnivores. Their diet consists of small fish, shellfish and squid. While fishermen occasionally find algae in their stomachs, scientists believe the sharks simply suck the algae along with their prey, not intending to use it as a food source.

Are Nurse Sharks Blind?

No, nurse sharks are not blind, but two species of carpet sharks are. All carpet sharks share similar features, making it easy to mistake one for another.

Are Nurse Sharks Gray?

No, nurse sharks are tawny. Although the Australian sand tiger shark is also sometimes called the gray nurse shark, the two species are quite different in appearance and temperament. They also live in different parts of the world, with nurse sharks living off the southern United States and sand tiger sharks off the coast of Australia.

To which kingdom do nurse sharks belong?

Nurse sharks belong to the animal kingdom.

Which category do nurse sharks belong to?

Nurse sharks belong to the class Chondrichthyes.

What phylum do nurse sharks belong to?

Nurse sharks belong to the phylum Chordate.

What family do nurse sharks belong to?

Nurse sharks belong to the Ginglymostomatidae family.

What order do nurse sharks belong to?

Nurse sharks belong to the order Anthodontidae.

What type of cover do nurse sharks have?

Nurse sharks are covered with smooth skin.

What genus do nurse sharks belong to?

Nurse sharks belong to the genus Ginglymostoma.

What type of habitat do nurse sharks live in?

Nurse sharks live in warm waters and tropical coastal areas.

What is the primary prey for nurse sharks?

Nurse sharks prey on squid, fish and octopus.

Who are the natural enemies of nurse sharks?

Predators of nurse sharks include humans, bull sharks and tiger sharks.

How many babies does a nurse shark have?

The average number of pups for nurse sharks is 20.

Any fun facts about nurse sharks?

Nurse Sharks are common in Central American waters!

What is the scientific name of the nurse shark?

The nurse shark's scientific name is Ginglymostoma cirratum.

What is the lifespan of a nurse shark?

Nurse sharks can live 20 to 25 years.

How Fast Are Nurse Sharks?

Nurse sharks can travel at speeds of up to 25 miles per hour.

What is the difference between a nurse shark and a gray nurse shark?

The main differences between nurse sharks and gray nurse sharks are appearance, teeth, size, reproduction, habitat and location.

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source
  1. Mark Mancini for Mental Floss, available here: https://www.mentalfloss.com/article/559319/nurse-shark-facts
  2. Aquaviews, available here: https://www.leisurepro.com/blog/explore-the-blue/carpet-bunch-7-families-carpet-sharks/
  3. How Stuff works, available here: https://animals.howstuffworks.com/fish/sharks/nurse-shark2.htm
  4. Wikipedia, available here: https://en.wikipedia.org/wiki/Sand_tiger_shark