Orangutan Crab

Orangutan Crab Facts

• This highly distinctive Arthropod most frequently goes by the simultaneously informative yet deceptive common name of the Orangutan Crab. It does have a few others that it’s known by, though. These terms include Hairy crab, Bubble coral crab, and Hairy orangutan crab.
• Within the scientific community, however, it’s possibly much better known by its solely technical designation. Sadly, like many such appellations, that’s somewhat difficult for the layperson to pronounce. That’s because this wonder bears the formal tag Achaeus japonicus.
• The truly remarkable animal received that specific epithet due to the efforts of Wilhem de Haan. That highly respected Dutch zoologist recorded the first formal recognition of it as a separate and distinct species. He achieved that scientifically noteworthy deed in the year 1839.
• Fortunately, the captivating creature appears to be maintaining both a stable and sufficient population base. That pleasant state also seems to hold true throughout the entirety of its known range. The IUCN thus does not currently place the animal on its published Red List.
• Nevertheless, the amazing work of Nature and evolution should be considered as facing several potential threats to its continued existence as a species, at least. Like all forms of life on earth, most of these stem from the actions of man. They include habitat loss and climate change.

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Orangutan Crab Physical Description

The uniquely-named Orangutan Crab easily grabs the attention of most individuals fortunate enough to encounter one of this marvels. They typically do so, however, due to more to their uncommon appearance than size. Despite its many other appeals, it remains a small Decapod.

It also follows an evolutionary pattern common among many of its relatives around the world. That’s the fact that it displays only a very slight degree of the physiological characteristic of sexual dimorphism. Distinguishing the genders purely visually thus is often difficult for casual observers.

In general, the carapace measures a mere 2 – 3 cm (0.8 – 1.2 cm) across. Among males of the species, this typically displays a narrower, more tapered shape than their female counterparts. They, meanwhile, generally have a broader, more rounded abdomen, used for carrying eggs when gravid.

In both sexes of this fascinating species, that shell usually develops as quite flat in nature, as well as roughly rounded. The unique color patterns this aspect of the animal presents frequently intrigues many viewers. This predominantly consists of various shades of reddish-orange to rusty brown.

The legs of this astounding Arthropod receive a great deal of attention, as well. These evolved as extremely long in relation to the body size, much like a spider. When fully extended, each of these ranges from 2 – 2.75 in (5 – 7 cm) in length. Together, this makes it seem much larger to the eye.

Perhaps the most fully distinctive feature of the Orangutan Crab remains the fact that virtually the entire creature possesses a dense covering of silky hairs! In coloring, these also precisely match that of the carapace and legs. This aspect understandably serves as the source of the general name.

Typical of its kind, its eyes evelop as small, appearing on stalks slightly protruding from the shell. The claws represent another aspect where it displays a small degree of sex-based differences. In both sexes these develop as small and delicate. Those of the males average slightly larger.

• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Malacostraca
• Order: Decapoda
• Family: Inachidae
• Genus: Achaeus
• Species: A. japonicus

Orangutan Crab Distribution, Habitat, and Ecology

The startling Orangutan Crab evolved as indigenous to a moderately expansive portion of the marine regions of the surface of the earth. Given its exotic nature, the exact location of that zone of habitation likely won’t surprise anyone. The marvel evolved as native to the Indo-Pacific region.

There, the product of Nature and evolution’s well known to appear throughout the greater area. In the Indian Ocean, though appearing in all portions, it seems to be especially prevalent in certain portions. These include the waters around Maldives, Western Indonesia, and in the Andaman Sea.

But, in the Paicific Ocean, its presence covers an even more extensive range. It inhabits the waters located near Indonesia, especially around Bali and Sulawesi. It also lives around the Great Barrier Reef, in Australia, the Philippines, Micronesia, southern Japan, Palau, Fiji, and the Solomon Islands.

Again following an evolutionary path common among its kindred across the globe, it evolved extremely specific preferences and requirements regarding its choice of habitat. This therefore has the effect of severely limiting its possibilites for expansion outside of its current territory.

In general, this stunning creation of evolution prefers to make its home in regions of tropical coral reefs. Even among such settings, though, it primarily resides in certain sections. These most frequently include areas composed of various lagoons, reef slopes, and protected reef flats.

It also displays a strong, though not exclusive, favoritism for bubble coral. The species additionally favors a specific range of depths. Most individuals live in waters between 10 – 100 ft (3 – 30 m) deep. Yet, even within this range, the majority of sighted examples appear between 33 – 66 ft (10 – 20 m).

The vast majority of the ecology of the impressive Orangutan Crab revolves around its commensal relationship with the aforementioned bubble coral. In fact, it lives almost exclusively on either this species of coral, or large-polyp stony corals. Here, it benefits from protection and camouflage.

It feeds as an omnivorous detrivore, consuming suspended plankton, organic detritus, and possibly mucus or trapped particles from the coral surface. In this, it employs the small, delicate claws Nature rpovided it with to pick its food off its surroundings without harming the coral.

Regardings its behavior, this marvelous animal defends itself solely through the tactics of avoidance and concealment. In this, its incredible coloring and hairy nature serve as excellent camouflage. Its main predators most likely include reef fish and invertebrate hunters like mantis shrimp.

Individuals usually tend to live principally solitary lives, generally congregating only to mate. Following this the female carries her eggs beneath her abdomen. Larvae are planktonic in nature, like its many relations. When she gives birth, the female disperses these through the water column.

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