view album Why we dive – animal behaviour
Observing animals in their natural habitat is one of the reasons people get up from their couch, put on the walking boots and head out into nature. Some animals require a little more initiative than Wellingtons and a Barbour coat because they happen to live in the sea.
We already know all sorts of interesting sea creatures and their lively habits from equally fascinating TV documentaries, but they tend to concentrate on the ’sexy’ animals like sharks and dolphins or the tiny and obscure like spawning corals. There are so many wonderful creatures in between the majestically huge and the humbly minuscule.
A night dive on the far-flung Indonesian island of Adonara provided me with an opportunity to witness a moment in the life of an olive shell. I got drawn to the action as my torch beam reflected off the silvery scales of a small fish. It was drifting in the current a few inches above the sandy bottom and it didn’t look too healthy. I plucked it out of midwater to look at it (the fish was dead) and left it to sink to the bottom.
Out of nowhere appeared a small shell and made as quickly as shells can crawl to the exact spot where the fish would hit the sand. The mantle of the shell extended and grabbed the fish. The shell proceeded to envelop the fish by turning its entire interior inside-out and wrapping itself around the fish. That must have been the moment when I started snapping pictures. The resulting sequence shows the shell up to the point where it disappears into the sand.
The predatory gastropod in question is an olive shell, which is described as a “carnivorous sand-burrower”. That description could hardly be more fitting after what I had witnessed in those 60 seconds under water.
I would have been very impressed by observing a dolphin mating ritual or a whale shark giving birth on that night dive, but there is more than just the life of the big and the famous.
To witness the lives of the curious and the obscure – that is why we dive.
See all images of this sequence in the album Feast of the olive shell:
The diving community breathed a sigh of relief today as 
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