Читать книгу Extreme Nature - Mark Carwardine - Страница 8

NAME	boxer crab, or pom pom crab, Lybia species
LOCATION	Indian and Pacific Oceans
ABILITY	packing a punch with anemone gloves

© Roger Steene/imagequest3d.com

Mutual relationships in the sea are common. A famous one is between a hermit crab and an anemone, where the former gains protection from the anemone’s stinging nematocysts, and the latter gets leftover food. Boxer crabs seem to have taken this a stage further. These tiny crabs – their carapace measures just 1.5cm (0.6in) – are prey to many animals. Their defence is to wield minute, stinging anemones on specialised claws. A jab with a ‘glove’ can cause pain (even to a human) or death and seems an effective defence – one boxer has even been observed seeing off a blue-ringed octopus. The anemones are also used in crab-to-crab boxing. But such fights are ritualistic, and boxing opponents hardly ever touch each other with their anemones, grappling instead with their walking legs.

When a growing boxer has to moult, it must put down its anemones and then grab them again when its new carapace (outer covering) has hardened. If it then finds itself with just one anemone, it merely breaks it in two, and the anemone obligingly duplicates itself. Surprisingly, the anemones don’t seem to object to being picked up or to being brandished in the face of a predator – at least, one hasn’t been seen trying to escape. And it’s hard to tell what it gets in return other than free travel, but since the boxer uses the anemone to stun food animals, maybe the anemone gets enough leftovers to make life on the claw worth it.