Galapagos Shark

The Galapagos shark is a type of Requiem shark. These sharks are found worldwide and are mostly seen in wide groups. They are active predators and are also known as the “Grey Reef Whaler”. They are often seen in large groups.  It was in the year 1905 that Galapagos shark was named from the specimens found near the Galapagos Islands. They sometimes approach boats or swim up high to divers, out of a sense of inquisitiveness. The shark has peculiar fusiform shape and is identified by their long dorsal fins. Biomimicry studies on Galapagos said that their skin pattern serves as a natural foul to bacteria.

This species of shark is not that dangerous to humans like that of the other ones. One can go for scuba diving with them without any risk, but all you need is to follow some common sense rules like watching them from distance and not dogging them for food.  Galapagos Sharks evolved some 100 million years before the dinosaurs did;the time period is long before human evolution. Modern forms of sharks evolved much before the Jurassic period. It was in the year 2008 the shark has been confirmed to have attacked two-three people.

Common Names

This shark is known by different names in different parts of the world

  • Cacao (Portugese)
  • Cazon (Spanish)
  • Mano (Hawaiian)
  • Malie (Samoan)
  • Requin De Galapagos (French)

Galapagos Shark Picture Picture 1 - Galapagos Shark

Description

The description given below will let you know how this species of  sharks looks like.

Size : Their maximum length is 3m and during birth they are 50-80 cm in height.

Shape : They have a form resembling to that of fusi and shape of a reef shark. It becomes difficult to differentiate this species from those dusky and large shaped sharks because of their shape.

Color : These sharks are brownish gray in color. They have pale white stripe on the side of their body.

Weight : Their maximum weight ranges to 85.5 kg.

Snout : Their snout is broad and curved.

Fins : These sharks have a pair of dorsal fins. The first fin originates over the posterior. The long pelvic fins are straight and each have a pointed tip.

Teeth : Their teeth in the upper jaw are jagged and triangular. But teeth in the lower jaw are narrower.

Distribution Range

The Galapagos shark is widely seen in tropical oceanic islands that includes Pacific Ocean, Indian Ocean and Atlantic Ocean. Wide population of this species are  found in continental waters off the Colombia, Baja California, Bermuda and eastern Australia. They are mainly circum-tropical. Recent report says that this species has also been seen in the continental waters off the Colombia, Australia, Guatemela and Baja California. There are about 19 types of sharks found in Hawaii and Galapagos is one of them.

Habitat

They prefer residing in clear, tropical waters. These sharks penetrate shallow bays in coastal waters and also venture into the surf. They found their niche in the vicinity of pinniped colonies and are caught at a depth of 4,119 ft. They are often seen congregating around sea mounts as well as rocky islets. They are not capable of surviving within small space like aquariums.

Behaviour

Their behavioural pattern is little bit similar to that of the Grey Reef Sharks.

  • Young sharks goes down the shallow water and tend to swim just off the bottom.
  • They become aggressive when there is a food stimulus like speared fish in water.
  • They are active predators by nature.
  • They can swim stiffly and have great speed. They have an average cruising speed of 3.2 km/h.
  • Sometimes, they exhibit a threat display of head swinging. This is one of their common habits.

Food and Diet

They love eating cephalopods and bony fishes. The larger one prefers varied diet that includes consumption of small sharks like sea lions, marine iguanas and many more. Also they have crustaceans and octopuses. This species of shark also eats squid, mackerel and flying fish. Galapagos are often seen attacking the fur seals and sea lions.

Photos of Galapagos Shark Picture 2 - Galapagos Shark Photo

Predators

Their biggest predators are Tiger sharks. They are often attacked by the tiger sharks. In case they are threatened by the predators, they arches their back, lowers it pectoral fins and swim in figure eight loops.

Adaptation

Galapagos sharks prefer residing in the Galapagos Islands because of their suitable adaptive features.

  • They are unafraid of human beings.
  • They have cartilaginous skeletal system that helps them fight with their predators.
  • Their mouth is wide enough to eat a human body.
  • Their upper teeth are triangular and serrated which means that they are dangerous and capable of fighting against human beings.
  • Their tall dorsal fins allow them to swim fast.
  • Their large body helps them cross open waters around oceanic islands.

Mating Season

Their mating season occurs early in the year (January to March) and gestation is estimated to be about 12 months. Their mating habit is bumpy. Female sharks have scars around their grills, fins and body from biting by the males during mating.

Reproduction

Galapagos shark are ovoviviparous and displays a viviparous (producing living young) mode of reproduction. They don’t reach their reproduction age before 10 years. The gestation period lasts for one year. They give birth to live pups after moving into shallow nursery areas. Their normal litter size is 4 to 16 pups, each babies measuring to 24-31 inches in length.

Life cycle

The birth size of the shark varies geographically. The juvenile ones stay in the shallow water to avoid any kind of threatening and predation. Males mature at the age of 6 years while the females mature at the age of 7 or 9 years. Before 10 years, none of the sex reaches the stage of sexual maturity.

Lifespan

Lifespan of this species is 24 years.

Conservation Status

Galapagos sharks are not at all endangered and are listed as close to susceptible on the IUCN Red list of threatened species. They usually have a slow reproductive rate and there is also heavy fishing pressure across its distribution worldwide.

Interesting facts

  • They are fast moving hunters.
  • They prefer warm waters.
  • Galapagos shark are quite picky eaters.
  • Human beings are often attacked by these sharks.
  • When their senses start tingling, have a look at them.’
  • This species are difficult to recognize in the field.
  • Shark finning is quite popular in some parts of the world. Shark finning is basically a graphical procedure of cutting off the fins from their body and the shark is then thrown overboard.
  • Galapagos are an easy target for fisheries.
  • Sometimes during group interactions, these sharks are seen commanding blacktip sharks.

Pictures

Here are given few images of Galapagos shark

Images of Galapagos Shark Picture 3 – Galapagos Shark Image

Pictures of Galapagos Shark Picture 4 – Galapagos Shark Picture

References

http://en.wikipedia.org/wiki/Galapagos_shark

http://www.montereybayaquarium.org/animals/AnimalDetails.aspx?enc=VsGX+Lst7QavzwfM9jiS1w==

http://www.aasharks.com/types-of-sharks/galapagos-shark.htm

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