From the Figi Postal Dept.:
Coconut Crabs in Fiji
October 20th, 2004
The coconut crab: Birgus latro (Fijian name:ugavule) is the largest land crab in the world. They can grow up to 2 feet in total spanned length and can weigh up to 10lbs. It is a type of hermot crab that has an Indo Pacific distributon but is confined to the islands only. It is not found on continental Africa, Australia, Asia or India.
It is also called the robber crab because of an interesting habit it possesses - the crab has been known to be attracted to shiny items and has the habit of stealing them!
Unlike other hermit crabs, this huge crab has developed a sense of comfort on land. it is so comfortable living on land, it has developed a skill to climb trees to get its favourite food and, it will even drown if submerged under water even for a few minutes. Interestingly, the coconit crab still breathes through gills. Its modified gills are surrounded with spongy tissues. To keep the gills moist, it will dip its legs into water and swipe them over the gills. From time to time, the coconut crab still needs to drink seawater to maintain the salt level in its body.
Apart from coconuts, it scavenges for other food including fruits and carrion. The powerful claws can tear a coconut apart. They also have elongated, pointed legs, which they use to climb trees and crawl over rocks easily.
Female coconut crabs can carry up to 100,000 eggs and go to the sea to shed them. The eggs hatch on contact with seawater releasing the young larvae to the sea. These develop in the sea and later come ashore as juvenile coconut crabs.
Juveniles live in a shell (like a hermit crab) but the adults live free. An adult tucks its strengthened adomen under the shell for protection. These crabs grow by molting (shedding their shell). They hide in shallow burrows when they molt and are very vulnerable to predators at this time. Adults are secretive, hiding by day in a burrow and feeding by night especially near human habitations.
Coconut crabs evolved with few predators in the Pacific Islands. Larval survival detremines the adult population size. Also, diminishing habitats from land clearing, heavy fishing pressure by humans, the huge demands from an ever-increasing human population and possibly mongoose have lead to coconut crabs diminishing vastly in numbers in Fiji. They are a delicacy in Asia thus they have become a valuable popular food item. They are rarely sold in local Fiji markets because of their scarcity.
The demise of the coconut industry and a rapidly developing tourism industry has increased the exploitation of this resource in this region. They are locally extinct in many populated areas in Fiji. However, they are common on many remote uninhabited islands and where it is deemed a prohibited food by some denominatiosn of the Church.
They can be lured to a staked piece of coconut bait and caught by hand after they appear. Alternatively they can be captured by human trickery! A piece of turf is placed on the coconut tree trunk about 3m from the ground. A descending crab reverses down the trunk and when its abdomen touches the turf, it lets go thinking it has reached the ground thus falling to the ground, knocking itself out, and is easily captured.
Coconut crabs need protection and conservation. They are so rare in Fiji that most of the urban dwellers have never seen one. Populations can be increased by artificial propagation and culture but these methods are not well researched yet. Ranching of coconut crabs is a possibility but finding juveniles in nature is difficult because they look like other species of hermit crabs.
The Marine Studies Program of the University of the South Pacific in Suva, Fiji promotes the conservation of coconut crabs and encourages further research into this unique animal.
**NOTE** Before some of you get too excited...these crabs have been red-listed as Threatened and even Extinct in some areas.
Coconut Crabs in Fiji
October 20th, 2004
The coconut crab: Birgus latro (Fijian name:ugavule) is the largest land crab in the world. They can grow up to 2 feet in total spanned length and can weigh up to 10lbs. It is a type of hermot crab that has an Indo Pacific distributon but is confined to the islands only. It is not found on continental Africa, Australia, Asia or India.
It is also called the robber crab because of an interesting habit it possesses - the crab has been known to be attracted to shiny items and has the habit of stealing them!
Unlike other hermit crabs, this huge crab has developed a sense of comfort on land. it is so comfortable living on land, it has developed a skill to climb trees to get its favourite food and, it will even drown if submerged under water even for a few minutes. Interestingly, the coconit crab still breathes through gills. Its modified gills are surrounded with spongy tissues. To keep the gills moist, it will dip its legs into water and swipe them over the gills. From time to time, the coconut crab still needs to drink seawater to maintain the salt level in its body.
Apart from coconuts, it scavenges for other food including fruits and carrion. The powerful claws can tear a coconut apart. They also have elongated, pointed legs, which they use to climb trees and crawl over rocks easily.
Female coconut crabs can carry up to 100,000 eggs and go to the sea to shed them. The eggs hatch on contact with seawater releasing the young larvae to the sea. These develop in the sea and later come ashore as juvenile coconut crabs.
Juveniles live in a shell (like a hermit crab) but the adults live free. An adult tucks its strengthened adomen under the shell for protection. These crabs grow by molting (shedding their shell). They hide in shallow burrows when they molt and are very vulnerable to predators at this time. Adults are secretive, hiding by day in a burrow and feeding by night especially near human habitations.
Coconut crabs evolved with few predators in the Pacific Islands. Larval survival detremines the adult population size. Also, diminishing habitats from land clearing, heavy fishing pressure by humans, the huge demands from an ever-increasing human population and possibly mongoose have lead to coconut crabs diminishing vastly in numbers in Fiji. They are a delicacy in Asia thus they have become a valuable popular food item. They are rarely sold in local Fiji markets because of their scarcity.
The demise of the coconut industry and a rapidly developing tourism industry has increased the exploitation of this resource in this region. They are locally extinct in many populated areas in Fiji. However, they are common on many remote uninhabited islands and where it is deemed a prohibited food by some denominatiosn of the Church.
They can be lured to a staked piece of coconut bait and caught by hand after they appear. Alternatively they can be captured by human trickery! A piece of turf is placed on the coconut tree trunk about 3m from the ground. A descending crab reverses down the trunk and when its abdomen touches the turf, it lets go thinking it has reached the ground thus falling to the ground, knocking itself out, and is easily captured.
Coconut crabs need protection and conservation. They are so rare in Fiji that most of the urban dwellers have never seen one. Populations can be increased by artificial propagation and culture but these methods are not well researched yet. Ranching of coconut crabs is a possibility but finding juveniles in nature is difficult because they look like other species of hermit crabs.
The Marine Studies Program of the University of the South Pacific in Suva, Fiji promotes the conservation of coconut crabs and encourages further research into this unique animal.
**NOTE** Before some of you get too excited...these crabs have been red-listed as Threatened and even Extinct in some areas.
