natural or man-made objects ( see photo of razor shell ) to reach elevated positions . This can improve their chances of filter feeding or avoiding predation by larger crabs and , when they climb up and sit on the shell of a large whelk , it may even bring the bonus of a lift to a carrion meal , which whelks are so expert at detecting .
Another common species is the anemone hermit crab ( Pagurus prideaux ). They invariably have a well-named cloak anemone wrapped around them but , if the crab is very small or the distinctive pink spots on the anemone ’ s base are obscured by a dusting of silt , this is easy to overlook . The anemone ’ s white tentacles are positioned underneath the crab in a good place to catch scraps of its food and can be hard to spot .
Hairy hermit crabs ( Pagurus cuanensis ) are distinguished by a dense fur of hairs all over their visible parts , especially their larger right-hand claw . Many of these crabs that I see have shells encased in orange or white sponge , with the sponge often much larger than the crab . A much rarer sight is one with a Parasitic anemone , a libellous name as explained in previous ‘ Critters ’. These anemones are usually only seen on large Common hermit crabs and even the smallest anemone towers over the diminutive Hairy hermit crab as it staggers along under the weight .
Plenty of other hermit crabs can be seen , with a total of 18 species found in our
Small Common hermit crabs clambering up an old Razor shell
waters , but they are generally much harder to recognise .
Attempts at identifying small hermits can even result in wonderful surprises . The sand at Brighton beach is a hot-spot for the south-claw crabs so when I went there once for a quick dip to cool off , I took my diving mask . As I crouched in the shallows and reached toward what I thought was the opening of an overturned hermit crab shell partly buried in the sand , it lifted up from the seabed and disappeared at speed . It was actually the spiracle ( breathing opening ) of a juvenile ray ! �
Pretty in pink – a very small Common hermit crab in a Painted top-shell
UKDIVING
Very small Anemone hermit crab ; the base of its Cloak anemone is difficult to discern on the shell but the tentacles are just visible underneath
Paul ’ s photos and video clips capturing UK marine life stories are on Instagram @ paulnaylormarinephoto
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