Coconut Crab Size & Facts: Strength in Contrasting with Other Crabs 2024

Coconut Crab Size & Facts: Strength in Contrasting with Other Crabs 2024

Last Updated on March 17, 2024 by themubbi63

The largest land crab in the world, the coconut crab (Birgus latro) is one of those crabs that spends all of its adult life on land. It shares this lifestyle with a variety of other hermit land crabs but isn’t one itself. 

The coconut crab is also the largest terrestrial arthropod, which is a sort of invertebrate that encompasses insects as well as spiders and centipedes. The coconut crab is mostly found in the Pacific and Indian Oceans.

Coconut Crab Size: Length and Width

Coconut Crab Length and Width

Given that it’s the largest arthropod in the world, let’s take a look at the length of the crab, shall we? The length of a crab is usually calculated in two ways. The first is the actual body length of the crab, which we’ll soon see. And the other is the legspan of the crab, from one legtip to the other legtip (which is much longer). This we shall discuss further on.

The actual body length of an adult coconut crab size is about 6 – 16 inches (15 – 40 cm). This is the length of the carapace. The width of the carapace is around 3 – 8 inches (7.6 – 20.3 cm).

Coconut Crab6 – 16 inches (15 – 40 cm)3 – 8 inches (7.6 – 20.3 cm)

Coconut Crab Weight

Coconut crabs are pretty hefty for a crab. This isn’t surprising at all, considering their size. In fact, it is the third heaviest crab in the world, just behind the Japanese Spider Crab and the Tasmanian Giant Crab. A fully grown coconut crab can weigh as much as 10 lb or 4.5 kg.

One thing that’s even more fascinating? The coconut crab is capable of lifting 6 times its weight. Yes, it is capable of lifting something that is 60 lb (27 kg).

Coconut Crab10 4.5

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Coconut Crab Legspan

As noted before, the legspan of a coconut crab is quite immense. In fact, for the largest specimens, it can reach 3 feet or 36 inches (91 cm). Male coconut crabs usually grow to larger sizes than female ones and their legspans are accordingly longer.

Coconut Crab Clutch Size

The reproduction process of the coconut crab is quite fascinating. As with all of their activity, all sexual relations happen on land. A female coconut crab can lay up to 250,000 eggs. She carries these fertilized eggs on the underside of her body for months until they’re ready to hatch.

Once the eggs are ready to hatch, the female goes to the edge of the water (usually on a rocky shore) and releases the larvae into the water. It’s a tricky process because the coconut crab herself cannot swim so she has to be careful not to be swept away. 

After this, it takes the larvae about 4 weeks to mature and find proper shells before they can migrate to the shore.

Coconut Crab Size Comparison to Humans

Coconut Crab Size Comparison to Humans

The coconut crab size is truly impressive when you think about it as compared to a human. An average sized human stands at about 5 feet 7 inches to 5 feet 9 inches. The legspan of a mature coconut crab size is 3 feet. That’s more than half the size of an average human being!

Heightwise, however, the coconut crab doesn’t compare. It stands at a maximum of 5.9 inches (15 cm) in height as compared to a human’s 69 inches (175 cm).

Related Article: Trapdoor Spider Size Explained & Compared With Other Spiders

Coconut Crab Size Vs Christmas Island Red Crab Size Comparison

Coconut Crab Vs Christmas Island Red Crab Size Comparison

Did you know that one of the places where coconut crabs can be found in very great amounts is the Australian territory of Christmas Island? Nor is it the only kind of crab found there. It isn’t even the majority. 

The coconut crab shares this island with millions of red crabs. These are the Christmas Island red crabs who are restricted to this island alone. The red crabs may win in numbers but they really don’t compare in size

The carapace width of a Christmas Island red crab is 4.6 inches wide as compared to the 8 inches of the coconut crab Size.

AnimalCarapace Width
Coconut Crab4.6 inches (11.6 cm)
Christmas Island Red Crab3 – 8 inches (7.6 – 20.3 cm)

Coconut Crab Size Vs Terrestrial Hermit Crabs Size Comparison

While the coconut crab isn’t a terrestrial hermit crab itself, it’s closest in kind to them. Thus, it’s only natural that we compare the two. We’ve got a wide range to choose from where the hermit crabs are concerned, but unlike the coconut crab, none grow very big.

Ranging from a body length of 0.47 to 4 inches (1.2 – 15.2 cm) and an average weight of less than 1 lb (454 g), it’s clear that land hermit crabs don’t really compare with coconut crabs at all. The coconut crab size, on the other hand, has an average body length of around 6 – 16 (15 – 40 cm) inches and an average body weight of 10 lb (4.5 kg).

Thus, while coconut crab size are closely related to the land hermit crab, it’s important to remember that they’re a different altogether.

Coconut Crab6 – 16 inches (15 – 40 cm)10 lb (4.5 kg)
Land Hermit Crab0.47 – 6 inches (1.2 – 15.2 cm) 1 oz – 1 lb (28 – 454 g)


Coconut crab sizes are truly amazing creatures. Their impressive size, strength, and unique life cycle make them stand out in the animal kingdom. Despite their name, they aren’t true hermit crabs and have adapted to a fully terrestrial life. These gentle giants are an important part of island ecosystems, and we should do our part to protect them.

Are coconut crabs related to hermit crabs?

Coconut crabs share a close evolutionary relationship with hermit crabs. However, there’s a key difference: while juvenile coconut crabs use discarded shells for protection, adults ditch the shell altogether and rely on their hard exoskeleton for defence. This adaptation allows them to grow much larger than their shell-dwelling cousins.

Where do coconut crabs live?

Coconut crabs are island dwellers, preferring the warm, humid climate of the Pacific and Indian Oceans. They’re particularly fond of tropical and subtropical islands, where they can find shelter, food, and suitable breeding grounds.

How much do coconut crabs weigh?

Don’t let their name fool you – coconut crab size is no lightweight crustaceans! They can tip the scales at a hefty 10 pounds (4.5 kilograms). That’s about the weight of a bowling ball! This impressive weight is thanks to their robust bodies and powerful muscles.

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