Bobbit Worm

Fascinating facts about the Bobbit Worm

• The biggest bobbit worm ever recorded measured an astonishing 299 cm in length, a size that makes it the longest known member of the polychaete class. This extreme length sits near the upper end of the species' overall size range, which extends from under 10 cm to almost 3 m. Even at this record size the animal remains remarkably slender, with a body width of only about 25.5 mm.
• The worm's mandibles stay hidden inside its body until a target passes, then they shoot out to strike and stun the prey. When they snap shut they are powerful enough to split some prey cleanly in half, delivering a rapid, lethal blow. These jaws are deployed from the worm's burrow after its five head antennae detect the approaching animal. The sudden, forceful strike allows the bobbit worm to capture fish and other creatures before they can escape.
• Burrow traces that match the bobbit worm's distinctive tunnels have been uncovered in fossil deposits near Taiwan, showing that its ambush hunting style has persisted for millions of years. Those fossilised L-shaped tunnels date back about 20 million years to the Miocene, indicating that ancestral species used the same buried-waiting strategy.
• The bobbit worm often faces coordinated attacks from schooling fish that aim to protect themselves. To reduce predation risk, some fish engage in mobbing behavior, during which a group of fish will direct jets of water into the worm's burrow to disorient it. The water blasts disorient the worm, reducing its ability to capture prey. This collective defence lowers the worm's hunting success in the immediate area.
• In home aquaria the bobbit worm is notoriously difficult to eliminate because it can survive being cut in half, with each fragment capable of forming a new individual. It also burrows into rocks and curls into tiny crevices, hiding despite its length. Smaller specimens often arrive unnoticed, hitching a ride in live rocks before growing larger inside the tank. Once established, its predation on fish can quickly deplete the aquarium's stock.

Sources

Every fact above was checked against these pages, and kept only where one of them states it.

• Wikipedia

At a glance

About the Bobbit Worm

The Bobbit Worm spends its entire adult life buried vertically in the ocean floor, exposing only its five sensory antennae at the surface. When a fish swims over, it lunges with jaws powerful enough to cut prey in half, dragging the victim underground to eat.

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