Wednesday, 2 March 2016

ON THE ROAD SURPRISES - Part 4 - Going Underwater

Scuba diving is unpredictable and always full of surprises which is what keeps me going back for more. I’m off to the Maldives next week for a diving trip, so I’m going to leave you with some underwater surprises and I’ll see you when I return at the end of March.

The first time I bumped into a Decorator crab I didn't realise what I was looking at. We were diving the Lembeh Strait in North Sulawesi and I saw a sea urchin moving impossibly quickly on the sand. It was only when I swam closer that I realised the urchin was perched on a crab. 

These crabs have spikes on their eco-skeletons which enable them to attach sponges, seaweeds, algae - and in the case of the crabs I saw in Lembeh - sea urchins, onto their backs as a form of disguise. I've even seen a decorator crab with an unwieldy mess of dead coral on its back, but alas I haven't been able to unearth that particular photo from my files.

I think there's
 something rather endearing about these little critters and I'm looking forward to a wealth of diving surprises in the Maldives next week.

As a result of a question put to me (see the comments) I did further research and discovered that my 'decorator crabs' are in fact 'urchin crabs' which resemble decorator crabs. The big difference being: urchin crabs carry sea urchins and decorator crabs carry sponges, hydroids, bits of algae and other inert objects on their shells. 

This is a classic case of believing what a dive leader told me without thoroughly checking the facts - so slapped wrist to me - and big thanks to AW for asking the questions that prompted my research.

In answer to AW's question about the advantages: the sea urchins benefit from being carted around by the crabs because they are transported to new feeding grounds. 


  1. Fascinating, Susan. Does this harm the creatures they attach or is it to mutual advantage?

  2. That's an interesting question, Ann. I don't believe it harms the sea urchin, but I'm not sure if it actually benefits it either. Hmm, I'll have to research this and get back to you! :)

  3. There are some weird things living in the sea, aren't there?

    At first glance, that sea urchin looked like a sweet chestnut. I suppose they both have spines for the same reasons.

  4. Don't get me started on 'weird', Patsy! The underwater world is a constant source of astonishment to me. I'll be posting more of the strange and wacky creatures in our oceans when I return from my dive trip. :)

  5. Pretty little guy! Enjoy your trip, Susan :) I'm joking of course- how could you not?

    1. Thanks, Jo - I intend to enjoy the dive trip providing I don't go down with a cold or ear infection (it happens!).

  6. Pretty little guy! Enjoy your trip, Susan :) I'm joking of course- how could you not?

  7. It's a whole other world, isn't it? Have all those strange aliens ever inspired you to write sci-fi?
    Have a great trip!

  8. Thanks, Linda. No, I couldn't write sci-fi to save my life - but one of my dive articles opened with the line: 'It looked like something from the movie, The Abyss...' :)


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