Horseshoe crab

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.

They are arthropods who 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.

You have guessed, 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 who feed mostly at night on worms and bivalves but can go a whole year without food and 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% each moult. 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.