Sharks and rays

Dusky shark (Carcharhinus obscurus)

Dusky shark
(Carcharhinus obscurus)

Occurring world wide, this shark can grow up to four meters. The characteristic feature of the dusky shark is its distinct inter-dorsal ridge. These sharks are known to feed in packs, with a diet consisting of game and reef fish, juvenile sharks, crabs, squid, octopus and crayfish. With well developed fins, and teeth designed to tear flesh, this shark is a powerful predator.

Honeycomb stingray (Himantura uarnak)

 

Honeycomb stingray
(Himantura uarnak)

This ray gets its name from the striking patterns of lines and dots found on its back. It can be found throughout the Indo-Pacific region. It feeds on a variety of foods, primarily bottom-dwelling fish and crustaceans. As with most stingrays it has a long tail with a single spine protruding from the base of the tail. These rays can reach two meters in disc width and weigh up to 120kg.

Pyjama catshark (Poroderma africanum)

 

 

Pyjama catshark
(Poroderma africanum)

This shy shark dwells in the colder waters of our coastline. Pyjama catsharks are light brown in colour and have distinct darker lines running from head to tail. The nasal barbels are the defining feature, giving the family the name 'catshark'. Spending most of its time on the seabed, this shark feeds on crayfish, crabs and fish.

Brown or sharpnosed stingray (Himantura gerrardi)

 

 

 

Brown or sharpnosed stingray
(Himantura gerrardi)

Brown stingrays are often found living in the surf zone, in estuaries and river mouths. They are also called sharpnosed stingrays because they have a distinct pointed snout. These animals are usually light brown in colour and have long whip like tails armed with spines. Stingrays are well suited to their bottom-dwelling lifestyle as they have a spiracle or breathing hole behind each eye which pump clean water over their gills. These animals are primarily found in the Western Indian Ocean.

Megalodon shark (C. megalodon) jawbone replica

Megalodon shark
(C. megalodon)

The megalodon was an ancient species of shark that may have grown up to 16 meters in length. By comparison, the great white shark grows to about 6m in length and the average human male is 1.8m.

Megalodons were super predators that lived in warm oceans with a plentiful supply of food.

Their extreme size means that they must have hunted very large prey, like whales and other marine mammals. Their jaws could open 1.8m wide and 2.1m high and contained approximately 276 teeth. Fossil teeth and vertebrae indicate that the Megalodon lived between about 25-million and 5-million years ago during the Miocene and Pliocene epochs. Originally the fossil teeth were thought to be dragon tongues until it was established they were in fact giant shark's teeth. The word megalodon means ‘giant tooth’.

It is highly unlikely that megalodon sharks still exist as the megalodon most probably became extinct during an Ice Age. This replica of a large megalodon jaw stationed at the entrance of uShaka Marine World presents an ideal photo opportunity for visitors. It is the largest in the world and was made in Durban by Hummingbird Studios.

Horseshoe crab (Limulus polyphemus)

Horseshoe crab
(Limulus polyphemus)

If you make your way to the Treasure Chest in the aquarium you will meet and perhaps touch an ultimate survivor. Ask one of the staff members on duty for them by name and then see if you are brave enough to connect with a living fossil. These are arthropods which are closely related to spiders, ticks and scorpions. They look like the fusion of a crab, spider and a ray. Their hard carapace protects their soft underbellies and their long straight rigid tail is not used in defence but to right themselves if they accidentally flip over or it can be used as a rudder.

They do not have gills like almost every other creature that lives in the ocean, but they have book gills shaped like the pages of a book for the exchange of respiratory gases as well as movement through the water. They are scavengers that feed mostly at night on worms and bivalves but can go a whole year without food. They live for about 25 years. They have few natural predators because of their tough exoskeleton. They are harvested for bait and fertilizer. At uShaka Sea World we feed them on pieces of prawn.

The females are bigger than the males and grow about 33% after each moult where the males only increase by approximately 25%. They will mount 16 times until they are fully grown and reach sexual maturity at 11 years. The horseshoe crab does not have haemoglobin in its blood, but has hemocyanin to carry oxygen. Because of the copper present in hemocyanin their blood is blue and is used extensively in the medical world.

These amazing creatures are amongst so many other fascinating animals living in the Aquarium at uShaka Sea World where the staff on hand are delighted to lead you on your journey of marine discovery.