It’s like a horror movie, of sorts – the octopus tank is empty; still, as if we’ve never had an octopus at all at the aquarium. And there, in the neighboring tank, is a crab shell without the crab; the husk of a crustacean. It’s apparent that a night prowler has wreaked havoc on the sandy-bottomed environment populated by peaceful organisms. The culprit can be none other than the aquarium’s resident octopus.
The only species of octopus which is documented to occur in Bermuda’s waters is the common octopus (Octopus vulgaris). With a mantle of 25cm and arms that can grow up to 1m long, these octopi are capable of being apex predators. They are one of the most intelligent marine organisms, demonstrating their ability to learn and solve puzzles. Octopi have the biggest brains (in proportion to body size) of any invertebrate, and posses more neurons than humans. What’s interesting is that all their neurons aren’t in their brain – some are in their arms.
In addition to their intelligence and power, these cephalopods are able to change the colour of their skin via use of chromatophores. Chromatophores are colour changing cells which occur in the thousands under the octopus’ skin to produce the transformations. Interestingly, octopus cannot see colour themselves; identifying their prey by movement, shape and scent. In addition, octopi can also chage the texture of their skin. This is achieved by contracting and expanding their papillae; small projections on their skin. Since octopi are soft bodied invertebrates, these extensive camouflage techniques are required for survival. As a last resort, octopi can also release a stringy ink in to the water column when threatened.
At the aquarium, tanks are left open at the top in order for them to be sufficiently supplied with oxygen. The octopus tank, however, is outfitted with artificial grass at the top, and wire mesh over the opening. The artificial grass’ strange feel is designed to deter any curious cephalopods from going walkabout around the aquarium. Unfortunately, the octopus tank is situated next to a tank containing many octopus delicacies – crabs, small fish and mollusks. Once an octopus realizes that there’s a whole world outside of their tank at the aquarium, it’s impossible to keep them any longer. Because of their intelligence, we change the octopus at the aquarium almost monthly, and, if they break out of their tank; sooner.
There was one octopus which escaped from the tank, was able to capture a small crustacean, and re-enter its own tank to eat. It’s certain that the intelligence and cunning of these organisms is nothing to be sniffed at.