Updated

Updated · BBC Discover Wildlife · Jun 16

Discover Wildlife Lists 9 Weird Crab Species, Including Toxic Killers and 4m Giants

Updated

Updated · BBC Discover Wildlife · Jun 16

Discover Wildlife Lists 9 Weird Crab Species, Including Toxic Killers and 4m Giants

Q: Can a 2026 breeding breakthrough save Japan's giant spider crabs, which live for a century, from being fished into extinction?

Not by itself. The 2026 captive-breeding success for Japanese giant spider crabs is an important conservation step, but it is unlikely to save the species unless it is paired with strict fishery controls and large-scale restocking. Japanese giant spider crabs can live for up to about 100 years and have already shown signs of heavy fishing pressure. Reported catches fell sharply from 24.7 tonnes in 1976 to 3.2 tonnes in 1985, a long-running warning that wild populations were being depleted. Japan has responded with seasonal fishing bans during the mating period, from January through April, and with efforts to release hatchery-raised young into the sea. The 2026 development matters because raising this species through its fragile larval stages to the juvenile stage is difficult. In April 2026, an aquarium succeeded in rearing larvae into juveniles about 1 centimeter long, adding to earlier successes in 2023 and 2025. That improves the practical basis for restocking and gives researchers better control over a species whose early life stages are hard to manage. But breeding progress is not the same as recovery in the wild. Whether it can prevent collapse depends on scale, survival after release, habitat conditions, and continued limits on harvest. For a long-lived species that matures slowly, overfishing can erase gains quickly. So the 2026 breakthrough could help protect Japan’s giant spider crabs, but it is best seen as one useful tool, not a standalone rescue.

Q: An invasive crab threatens Alaska's fisheries. How can citizens identify this 'cockroach of the sea' before it's too late?

The invasive species Alaskans need to watch for is the European green crab, and the clearest way to identify it is by counting five sharp spines behind each eye on the shell. That feature is the most reliable marker and remains visible even on molted shells. Citizens should not rely on color. Despite its name, the crab may be green, brown, red or orange. Its shell is usually wider at the front than the back, and adults are relatively small, typically up to about 4 inches across. It also has long legs and narrower claws than many native crabs. If a crab is much larger than 4 inches, it is probably not a green crab. People are most likely to find them in sheltered coastal habitat rather than surf-exposed beaches: rocky shores, cobble beaches, mudflats, salt marshes, lagoons and estuaries, especially around eelgrass. They often hide under rocks, shells and debris, or bury themselves in mud and sand. The threat is serious because green crabs prey on juvenile king crab and salmon, damage eelgrass beds and compete with native species such as Dungeness crab. That is why they are often called the “cockroach of the sea” for their hardiness and destructive spread. If someone finds a suspected green crab, they should photograph it clearly with an object for scale, avoid releasing it, and report it immediately to Alaska’s invasive species authorities, including the statewide hotline at 877-468-2748. Early reporting is critical to protecting Alaska’s fisheries.

1 articles · Updated · BBC Discover Wildlife · Jun 16

Discover Wildlife highlighted nine unusual crab species, led by xanthid and devil crabs whose toxins survive cooking and have no antidote.
Nearly 4m Japanese spider crabs anchor the size extreme, weighing about 13.6kg and living up to 100 years despite becoming vulnerable when they shed their shells.
Several entries challenge the label itself: porcelain crabs and hermit crabs are not true crabs, with porcelain crabs evolving a crab-like form through carcinisation.
Other odd adaptations include boxer crabs wielding sea anemones for defense and feeding, spanner crabs walking forward and backward instead of sideways, and zebra crabs living parasitically among venomous sea urchins.

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BBC Discover Wildlife1d ago

Discover Wildlife Details 9 Weirdest Crab Species, Including Toxic Killers and 4m Giants

Why do unrelated sea creatures keep evolving into crabs, with some becoming so toxic that cooking cannot make them safe to eat?

Can a 2026 breeding breakthrough save Japan's giant spider crabs, which live for a century, from being fished into extinction?

An invasive crab threatens Alaska's fisheries. How can citizens identify this 'cockroach of the sea' before it's too late?

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1 total

BBC Discover Wildlife1d ago

Discover Wildlife Details 9 Weirdest Crab Species, Including Toxic Killers and 4m Giants

Discover Wildlife Lists 9 Weird Crab Species, Including Toxic Killers and 4m Giants

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