Image: Osedax sp

Osedax sp

Family Siboglinidae: Osedax sp. (Photographed alive in a laboratory aquarium)

Greg Rouse
© Greg Rouse


These are gutless worms living on the bones of a whale which has found its grave on the seafloor at 633 m in the Monterey Canyon, USA. They are commonly called ‘boneworms’ or ‘zombie worms’, they range in length from 6 to 8 cm. The animals in the photograph are all females which attach to the bones by root-like structures full of friendly symbiotic bacteria that dissolve the bones, thus providing nutrition. Males are too small to be seen because they are no more than tiny bags of sperm hidden inside the female tubes, in harem-like groups, and their only function is to produce sperm. Males also lack symbiotic bacteria and rely solely on females for food in the form of embryonic yolk reserves to fulfil their ’destiny’. In this photograph fertilised eggs are being spawned into the water column. This group of bone-devouring worms was only discovered in 2004 and other species have since been described from many locations world-wide, feeding on bones of marine mammals and large fish.

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