Hitchin' a ride: Brittle star gets a lift on larger starfish

Get on board. This six-armed brittle star is hitching a ride on its giant neighbour, a blue sea star.

This shot was taken in the warm, shallow waters of the Solomon Islands, a scattering of more than 900 islands east of Papua New Guinea known for their coral reefs. Both species scavenge the ocean floor for food at night.

Getting a lift like this won’t be possible for long. It might look small now, but this juvenile brittle star (Ophiothrix spp) will eventually grow arms that are up to 60 centimetres long, twice the size of a typical blue sea star (Linckia laevigata). Both also regrow arms that they lose.

While neither is listed as endangered, in some regions their populations are falling due to over harvesting by the aquarium and tourism industries.

This article appeared in print under the headline “Hitchin’ a ride”