HORSESHOE CRAB, commonly referred to as the ’living fossil’ is all set to join the long list of the endangered species. Decline in number of horseshoe crabs has become a matter of big concern for wildlife scientists as well as activists. Extinction of horseshoe crabs is a big threat for pharmaceutical, clinical and food industries, and the ecological balance as well.
Once named Horsefoot Crabs because of the resemblance of their shell to a horse hoof, the Horseshoe Crab is originally not a crab. In fact, horseshoe crabs have their own classification and belong to Class Merostomata of Arthropoda Phylum. A hard-shelled invertebrate, horseshoe crab lives in warm, shallow coastal waters on the sea floor.
Commonly found along the coastal region, horseshoe crabs have existed for more than 250 million years on earth. Despite geographical changes in millions of years, horseshoe crabs evolved a little. Horseshoe crabs survived due to their hard, curved shells, which saved them from predators. Besides, horseshoe crab can survive without eating a year and can endure extreme temperature conditions and salinity as well.
The arthropods are considered an important species for medicinal research and also have special value in pharmaceutical, clinical and food industries. Horseshoe crabs found in Indian subcontinent also work as indicators of the health of the coastal zone. Medicine experts say that horseshoe crabs have properties to treat diseases such as typhoid and meningitis. In addition, the medicine from horseshoe crab acts as a painkiller and can be used on burn victims and skin-graft donors.
In the 1900s, after drying, horseshoe crabs were used as fertilizer and poultry food supplements. Long survival of horseshoe crabs has given scientists a good resource to know more about the immuno-defensive mechanisms and perfection in their biological and physiological processes. This unique characteristic of the horseshoe crabs has enabled scientists to use it in space to look for proof of any illness in outer space.
Fact is that horseshoe crabs have played a vital role in anyone’s life who has received an injectable medication. An extract from the horseshoe crab’s blue, copper-based blood called ’lysate’ is used to test the purity of medicines. Pharmaceutical and medical device companies use the crab’s blood to ensure that their products such as intravenous drugs, vaccines and medical devices, are free of bacterial contamination. No other test other than horseshoe crabs works as easily and reliably for this purpose. Shells of horseshoe crabs have also been used to speed blood clotting and to make absorbable sutures.
Horseshoe crabs have important ecological role in the food chain. Decrease the species would affect other species in food chain, especially shorebirds who feed on the eggs of horseshoe crabs exposed on the surface. Sea turtles also feed on adult horseshoe crabs. Hence, decline in number of horseshoe crabs will destabilise the food chain.
To save the horseshoe crabs from complete extinction, world scientists are demanding to include the invertebrate in the Schedule IV of the Wild Life Act for labelling the crabs as endangered species. Of course, the Act will check the improper use of horseshoe crab for various purposes, but it looks almost impossible to significantly increase the number of the arthropod in future.