The coconut crab (Birgus latro) is an arthropod with an interesting biology. This monstrous being is also called as thief crab because of its desire for stealing shiny objects from houses and tents. It is famous as a land crustacean and the heaviest terrestrial arthropod that exists. It weighs anywhere between 5 and 9 kilograms. Their natural habitat is in the islands of the Pacific and Indian Ocean, with the largest population on Christmas Island in the Indian Ocean. They are spread across islands and in different colors that vary between violet, purple and brown.
Welcome…Meet the coconut crab, a coconut opening arthropod and its incredible facts…
1 Areas of presence
The coconut crab is found in places like Christmas Island in Australia, and in the areas from the Indian Ocean to the west of the Pacific Ocean. They are also spread across a large number of islands in the Indian and central Pacific Oceans, hiding in burrows and crevices near the coast. Their life span may reach up to 60 years.
2 Lives of Coconut Crabs
Video Credit: Anke Heldmann
The coconut crabs are the largest terrestrial arthropods. In some places they are famous as crab-thief-of-coconuts or coconut crab (in English), as they are strong enough to climb coconut trees and steal coconuts. In addition, the crabs can also make holes in them, with their powerful claws. This makes it easier for them to taste the inner side of the coconut. These crabs can live from 10 to 30 years.
These crabs cannot swim, once they are out of their larval state. They drown if they accidentally fall into the water. The branchiostegal lung is their organ of breathing, an organ that is something like a cross between gills and lungs. They are animals with nocturnal habits, and this is why they are hardly caught stealing during the day.
3 Dimensions and Size
These crabs are giant creatures spanning as long as 1 meter and weighing as much as 17 kilos. This is really spectacular considering the fact that it is an earthly arthropod. Larger specimens can be found in the aquatic environment. The males are much larger than the females. In addition, they come in a wide range of colors, ranging from red to blue.
4 Eating Habits
Coconut crabs feed on fruits such as coconuts and figs. However, they can also eat various things of organic origin, from turtle eggs to other animals and leaves.
5 Importance in local cuisine
The coconut crabs are considered a delicacy in the Islands of the Pacific Ocean, and are served in local cuisine. Several special dishes that include the crab line up the menu.
Video credit: Famous Cuisines Channel
6 Strange Characteristics of Coconut Crab
This animal is not poisonous in nature but has the tendency to acquire toxins that make it poisonous through its food. Several cases were reported where the crab ate plants that contained toxins and became poisonous. It does not attack the human being, since it does not bother him.
7 Amazing Sense of Smell
These animals have a very developed and dedicated sense of smell. In fact a major part of the brain is dedicated to sensing odors and smells. They can smell potential food sources from a distance.
8 Reproductions in Coconut Crabs
Video Credit: Christiana Anagnostou
Mating between these crabs takes place on land and in the months between May and September. The female carries the eggs with her until they hatch. The eggs are released into the water near the shore.
After a few months, small larvae hatch from these eggs. These larvae become young crabs.
9 Why the coconut crabs are named so?
Coconut crabs are named so because they feed mainly on coconuts, and have a characteristic ability for it. The pliers render them able to penetrate the hard shell of the coconut. In addition they employ a special technique to be able to open them. If the coconut still has its outer covering, he uses its tongs to pull it into strips. Once the points of germination i.e. the three small circles are visible, the crab hits one of them with its tweezers until it pierces it to the pulp.
10 Hunting and the search for food
During the night the crabs go out to look for food. If they find no coconut available on the ground, they climb trees to eat coconuts or other fruits. The day time goes usually in hiding in the cracks of rocks or in burrows. In case of food shortage, it leaves the day in search of palm trees to protect it from heat or from predators.
Larger crabs reach up to 40cm and the legs get a wingspan of 1m. This favorable physical characteristic allows them to break the coconuts in several pieces and eat them easily. They also occasionally feed on bird or turtle eggs, plants and other animals’ corpses. They are able to eat animals like young sea turtles, or animals of up to 30 kilograms. They have a very poor view but it is compensated with an excellent sense of smell that allows them to detect possible foods over long distances.
11 The Unique Aquatic Organism
Something really unique and curious about crabs is that it is aquatic only during the first two months of its life. After that it turns completely terrestrial to the point of drowning in the water. In order to breathe smoothly, it uses a special organ called the brachial lung. It can be defined as an intermediate evolutionary stage between gills and lungs and is one of the most characteristic adaptations of the species to its ecosystem.
12 Other Utilities of the giant crab
They are raised by locals and used as a keeper of the coconut plantations. The coconut crab is threatened by intensive hunting as it is considered a delicacy (served with coconut milk) on many islands. Recent years have seen uncontrolled development along the coast of the islands and that has modified or destroyed much of the habitat of this crab. The increase in tourism has also made them captive and escalated to their trade, and also as ornaments.
13 Extinct or Not?
The coconut crabs have been reported to disappear from the islands of Australia and Madagascar because of excessive hunting. Whether it is endangered or not, is a matter of speculation. What is sure is the significant drop in numbers on many islands. The predation by pigs, rats, lizards and monkeys are also a threat to young crabs. There have been reports of intoxication from eating meat.
14 The Antisocial Being
Adult coconut crabs live in burrows. These crabs maintained utmost privacy and make any intruder crab their meal. The antisocial character doesn’t ends here. They maintain a fair distance while out to hunt for food. The coconut crabs do not even come to visit at a common spot.