This cuttlefish instantly went dark as it swam over the kelp frond
Like sea scorpions , flatfish are also skilled at blending in , as exemplified by this young dab
While sea scorpions and other fish are relatively slow to change colour and can ‘ stick out like sore thumbs ’ if they have to move from their favoured spot , that supreme chameleon of the sea , the cuttlefish , has no such problems . I love watching the way they can alter their shade and pattern instantly , while swimming over strips of dark kelp on a pale sandy seabed .
If you can ’ t change yourself to match the scenery , why not carry the scenery around with you ? That ’ s what spider crabs do , ‘ decorating ’ their armour with seaweed , sponge or whatever is about , even sometimes including ( sadly ) litter . The ‘ decoration ’ can be quite extravagant , especially when the seaweed continues to grow in situ , and I ’ m sure most UK divers have had the startling experience of seeing a ‘ clump of seaweed ’ get up and walk off when we get too close !
A further intriguing aspect of camouflage , or the lack of it , is when the need to impress partners overrides the advantage of keeping a low profile . My favourite example is the blackfaced blenny , a relative newcomer to our shores which is generally rare , but a regular sight at certain spots in the southwest . The females are incredibly well camouflaged in the ‘ turf ’ of seaweed and encrusting animals on reef walls and overhangs . I find it is usually just their movement or the glint of an eye that gives them away but , like the sea scorpion , how many do I miss ?
For much of the year , the male follows the female ’ s suit but , boy , how he throws it all out of the window in the summer breeding season ! He dramatically changes his livery to a black head and brilliant yellow or orange body , often with pretty pale blue fin edging . This must help entice visiting females and , while we might wonder how many of these colourful and now obvious Lotharios get snaffled by predators , we know one thing from the logic of natural selection and evolution . It must be worth it ! �
Beautifully blended in sea scorpion waits for prey in the recent winter clarity of Falmouth
Spider crab with an impressive camouflage ‘ garden ’ on her carapace
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