wetlands
a publication of Sungei Buloh Nature Park

Vol 8 No 2
Aug 2001


survivors of time: the horseshoe crab

insect study
tips on insect watching

zonation:
the landward mangrove fringe

landmark invasion
a walk in the past

fat worries of common
redshanks


Allan Teo
long-lasting companion
of the park

young naturalists
of the park

a nature journal
javan munia
 
survivors
of time
linda goh
senior education officer

presents some interesting facts about these old timers
Their ancestors were present to witness the rise and fall of the Dinosaurs. As dinosaurs struggled to survive, these creatures managed to outlast them for millions of years with apparently little change. In our present age, these living "fossils" which cross two boundaries, namely the sea and land's edge are called the Horseshoe Crabs.

what crab! no crab! The name Horseshoe was derived from the U shape of the shell that resembles the hoof of a horse. However, Horseshoe Crabs are not crabs. They are more closely related to spiders and scorpions.

survival series To date only 4 species of Horseshoe Crab have survived, ff which 3 species can be found in the Southeast Asian region. The tough mantle of the Horseshoe Crab prevents any potential predators from accessing the soft-bellied underparts. They have no known natural enemies except perhaps Man. Their capacity to endure extreme temperatures and salinity is believed to help to ensure the survival of these species. Slow and steady, they are indeed the real survivors of time.

mudflat cuisine Horseshoe Crabs are scavengers and feed on whatever they meet on the mudflats. They do not have jaws and have to depend on the stiff hairs on the base of their legs to grind food. In other words, they have to walk in order to chew!

growing years Growing is by means of moulting. After each moult, they emerge 25% larger than the last. It takes about 16 moults before they attain adulthood. They are sexually mature individuals at the age of 9 to 11 years. These creatures can live up to 19 years.

body parts The menacing looking tall gives the illusion that it is used as a weapon. However, the telson or tail acts as a rudder to steer the Horseshoe Crab through the sand and to right itself when it accidentally tips over.

battle of the sexes Males hitch-hiking on the females can be observed during the mating season. The males, which are much smaller, cling on to the females for long periods of time before the eggs are laid in dug out nests. That is why some locals identify the Horseshoe Crabs with matrimonial fidelity.

eye-deal Horseshoe Crabs have been used for eye research as their large eyes and large optic nerve are easy to study. A great deal of what we know of the human eye and how we see are attributed to research done on their eyes.

royal blood Two biologists from NUS had a breakthrough when they discovered an enzyme known as Factor C that is extracted from the Horseshoe Crab's blood. This enzyme has shown to be more powerful and efficient in killing bacteria then the common antibotics. 4 US patents have been obtained for the replicated gene.

The Horseshoe Crabs have successfully survived for millions of years. Their future depends on how much people understand and appreciate their importance to other wildlife and Man as well as the conservation practices taken to conserve them.

Help Sungei Buloh Nature Park to protect these animals by taking care of their habitat!
   
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