Facts About Nurse Sharks
I think it is difficult to associate a nurse with a shark. That is why the name “nurse shark” sounds so peculiar to our ears. So, let us know some facts about nurse sharks.
Scientific Name: Ginglymostoma cirratum
These sharks belong to the family Ginglymostomatidae. These are a type of carpet sharks. All the members of the family are sluggish bottom dwellers. The lifespan of an individual is about 15 to 25 years.
Experts are not sure about the source or reason of the common name of the shark. Some thinks that the term “nurse” actually came from “nusse” which means “catfish”. Some people (especially in the Caribbean) call it a “nurf shark”.
Description and Anatomy
These sharks are brown or grey in color. The dorsal and pectoral fins of a nurse shark are rounded. The caudal fin is long. The head of the marine animal is rounded and flat. There are two short barbels just above the mouth. These barbels are sensors to catch the hidden prey.
The eyes of the species are relatively small. There are two circular openings behind the eyes. These are spiracles which helps them to breath. It looks more like a catfish than a shark.
The mouth of the shark is full with teeth. These are curved inside to catch the prey. It is most helpful to grab the slippery fishes.
We have already mentioned that the nurse sharks are bottom dwellers. They can be seen near the coasts of tropical and sub-tropical oceans. They generally live in the oceanic depth of 30 to 250 ft (10 to 85 m). Sometimes they come to the very shallow waters near the coasts.
The Atlantic coast of South America and Africa is a common place to found these sharks. They are very common in the waters near the Caribbean islands. Some specimens are also present in the Pacific coast of North America.
Nurse Shark Size and Weight
These sharks are big in size. The individuals can be as long as 10 ft (3.1 m). There can be bigger specimens. The biggest nurse shark was 15 ft (4.5 m) with a body mass of 330 kg (730 lb). But some people believe that the report is exaggerated.
Nurse sharks are carnivores like other sharks. There mouth is small to catch big fishes. So, they limit their diet with smaller fishes and crustaceans.
These sharks are bottom dwellers and slow to move, so they can’t catch faster fishes. They search for hidden crabs and shrimps from sand to eat. These sharks can sense the hidden prey with their sensors. After that, they suck the sands to get the unfortunate creature into their mouth.
Nurse sharks also eat mollusks like small squids and octopuses. They also feed on tunicates that live in the sea bottoms and coral reefs. Bottom dweller sting rays often become prey to them.
They suck the flesh out of sea shells. They flip the shells down and suck the bottom openings of the shells. The force of the process drags the meat out of the hard shells.
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|A Group of Nurse Sharks|
These sharks spend all day lying in the dark or semi-dark sea floors and between the rocks and coral growths. They are nocturnal hunters.
Unlike most other sharks, they need not to always in the move to breath. They suck water with its mouth to keep the oxygen flow intact over the gills. The spiracles are used to eject excess water and unwanted particles.
Often these sharks can be found in large groups. These groups live in a particular area of the ocean for mutual protection. But there is no group or social interaction between the individuals. There is no pack leader to follow. There are also no group hunting or group movements to one direction.
|Nurse Shark Egg|
The nurse sharks carry the egg inside their body. After a period of six months, the baby sharks come out from the mother’s womb. They generally give birth to 10-40 pups at a time. The babies in the mother’s “womb” do not get any nourishment from the mom’s body. The food is supplied to each baby from its own yolk sacks.
The mating season is June and July. The female sharks are being bitten by the males during the mating. As a result, often the females become wounded by being beaten by several males. The females can reproduce once in every 18 months.
Baby Nurse Sharks
The baby nurse sharks are about 1 ft (30 cm) long during birth. The babies have spotted skins. A nurse shark baby is left alone by the mom just after the birth. That makes them vulnerable to predators.
The number one enemy of a baby is its stronger siblings. The strong ones often kill and eat the weak brothers and sisters. This type of cannibalism is common among these sharks.
Nurse Shark Attack
Do nurse sharks bite humans? No, they are not an aggressive species. They also tend to avoid larger animals like humans. One can go near a resting individual without much fear. But provocation may lead to a sharp bite. A nurse shark can be dangerous if you try to catch it with bare hands.
Nurse sharks are not targeted by fisheries. That is why they are not a threatened species. Some people haunt them for liver well and skin. But the number of human haunters of the fish is limited. Sometimes, they become by catches in deep sea fishing nets.
The juveniles are often collected for aquarium tread because of the spotted body color. But it is difficult to keep a large full grown one in an aquarium. That is why these sharks are not too popular in the industry.
The rate of reproduction of these sharks is slow. But there rate of metabolism is very low. They also remain lying in the sea floor for hours. As a result, they need little food to survive. It makes their chance of survival greater than an active predator like great white.
Nurse Shark Pictures
Here are some images of the shark. Feel free to share these photos with friends via Pinterest.
Do you have any question regarding these sharks? You can ask anything. We will answer as soon as possible.
Read More About Sharks
You can read our other articles about sharks. Learn 50 facts about tiger sharks or about port jackson sharks. Do you want to know that is shark a fish ? There is an interesting article about top 20 weird sharks on earth.
Do you know about less popular sharks like brown banded bamboo sharks or Dogfish?