Coconut Crab Size: 'Claw-some' Ocean Robber Facts That Kids Will Adore

Akinwalere Olaleye
Oct 27, 2023 By Akinwalere Olaleye
Originally Published on Nov 24, 2021
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Coconut crab on a palm tree

The coconut crab, genus Birgus Latro, has many other local names such as Ayuyu, Unga or Kaveu.

Known to be amongst the biggest crabs of the world, the weight of the coconut crab is 8 lb (4 kg), its body length is 15 in (381 mm), and it has a leg span of around one meter, with males being larger than females.

Other reports have spoken about a crab with a weight of up to 37 lb (17 kg) and a body length of up to 39 in (1 m). This is believed to be the limit of the terrestrial arthropod.

The female is about 40 in (1 m) from leg to leg.

Coconut crabs vary in size, but reports say that the coconut crab has 10 legs, an abdomen, and strong claws to open coconuts. The claws can carry weight up to 63 lb (29 kg).

Their walking legs have small claws that are like tweezers at their ends. These legs can help the coconut crab climb trees up to 236 in (6 m) in height. The last pair of legs are very small and are used to clean their breathing organs.

The squeeze of their pincers can be stronger than any human's grip. The bigger the crab is, the stronger its force is.

If you enjoy this article, why not also read some land crab facts or about the quetzalcoatlus's size here on Kidadl?

Is the coconut crab the biggest crab?

The coconut crab, Birgus Latro, is the second-largest crab in the world.

It is also known for its ability to crack open coconuts using its pincers in order to get the contents of the coconut out. The coconut crab is also famously known as the robber or palm thief.

The coconut crab is not quite the world's largest crab. The largest crab is the Japanese spider crab and also the biggest crab to ever be caught; this crab can easily reach 12 ft (3.7 m) from one claw to the other claw.

The coconut crab is the largest crustacean that spends most of its life on land. It also has a Guinness world record to prove it.

It is the biggest arthropod and can live up to 60 years and reach sexual maturity at around five years. It is called the robber crab or palm thief as some coconut crabs often steal silverware or shiny items from people's houses.

The coconut crab's other name is the terrestrial hermit crab because coconut crabs' shells are used by many other young animals. It is known that coconut crabs eat coconuts in the wild.

A coconut crab also has an excellent sense of smell that it can use to detect its food. They are also attracted to the smell of blood.

Their diet consists of mainly fleshy fruits, such as seeds, drupes, nuts and fallen trees. Being omnivores, they also feed on other organic matter like hatchlings of tortoises and dead animals. One large coconut crab was seen killing and devouring a Polynesian rat during a tagging experiment.

It has been observed that these animals can climb trees and can get down by falling. They can survive at 15 ft (4.5 m) fall unhurt. As terrestrial crabs, coconut crabs have air-breathing organs because they spend most of their lives out of water.

After juvenile coconut crabs have matured and are kept in water for a long period of time, they can drown. Living on an island, these crabs do drink fresh water.

How long does it take for a coconut crab to reach full size?

The coconut crab begins its life like any other hermit crab. The female crabs release their eggs into the ocean.

The eggs float around on the surface of the ocean for 17-20 days prior to sinking and reaching the floor. In the sea, coconut crabs develop small mollusk-like shells.

Young coconut crabs then make their way to the shore. After the small crabs reach land, they trade in their mollusk shells for gastropod shells. They then compete with other coconut crabs for food on the shore, which lasts around 28 days.

The coconut crabs then give up their shell once they reach about one inch (2.54 cm). They do not get another shell but rather grow an exoskeleton to protect their entire body.

The crab moves on land once it reaches full maturity and only female crabs return to the ocean to deposit their eggs. When the crab is molting, its exoskeleton starts to swell. For females, the abdomen might also swell due to its growth.

During the molting period, these crabs spend their time in their burrows dug in loose soil. They sit nearly 39 in (1 m) away from the entrance.

This is to keep them safe from predators such as rats or other crabs. Coconut crabs take minerals from their exoskeletons. Due to this, they lose mobility.

Their exoskeletons are never found because coconut crabs eat away their exoskeleton to gain their nutrients. Coconut crabs have a slow growth rate and molt throughout their lives; they only reach full size after 40-60 years.

Can you eat large coconut crabs?

Adult coconut crabs have no known predators other than coconut crabs and humans.

Coconut crabs are very rare on an island with a human population and get hunted for their size and quality of white flesh. On various islands, the coconut crab is a delicacy.

Due to the intensive hunting that the species experiences, its existence is threatened in some areas, causing a decrease in the coconut crab population. Crabs and other seafood are eaten by millions worldwide, due to their rich nutrients and are considered to be healthy. So, the answer to this question is yes; you can eat coconut crabs.

Coconut crabs are eaten by many people on the islands of the Pacific and the South Pacific. Coconut crabs are considered a delicacy, and these crabs are a protected species.

In the Mariana Islands, this crab is called Ayuyu, and in the Cook Islands, it is called Unga or Kaveu. These islands' Coconut crab populations have declined in several areas or are almost extinct due to their habitat loss.

They are mostly found in the Indian ocean. In 1981 they were listed as a vulnerable species.

The slow population growth rate can be a problem for the survival of the species. There are regulations to help in the protection of coconut crabs across the Pacific Island that they inhabit, although the specifics are determined by each country.

Minimum harvest is used on many Pacific Islands. In some locations, females producing eggs are also specifically protected.

Some governments have also set quotas as to how many crabs can be caught, and permits are required to export these species. It is known that in some areas, exporting crabs is completely prohibited.

Another threat to these species is their total loss of island homes from rising sea levels caused by climate change. This is a very big threat to these kinds of habitats, with many at risk of being lost in the huge ocean.

Do coconut crabs steal shiny things?

Coconut crabs are well-known as robber crabs or palm thieves due to their robbery of small and shiny items from humans' houses. They have been known to steal cutlery, bottles, pots, pans, and wristwatches.

Coconut crabs are stealthy when they snatch and drag their body far into the bushes before testing the item's edibility. It is a very good tactic to get away from humans, but it also annoys people.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked reading about the size of coconut crabs, then why not take a look at our articles on mussels vs clams or lions vs tigers?

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Written by Akinwalere Olaleye

Bachelor of Arts specializing in English Literature

Akinwalere Olaleye picture

Akinwalere OlaleyeBachelor of Arts specializing in English Literature

As a highly motivated, detail-oriented, and energetic individual, Olaleye's expertise lies in administrative and management operations. With extensive knowledge as an Editor and Communications Analyst, Olaleye excels in editing, writing, and media relations. Her commitment to upholding professional ethics and driving organizational growth sets her apart. She has a bachelor's degree in English Literature from the University of Benin, Edo State. 

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