A tale of two octopuses



Part One: Rocks and jars
    As part of our behind-the-scenes tour of the aquarium, we got to meet many of the trainers who work closely with the animals.  Part of the reason they undergo training is so that they will be cooperative during medical procedures and to occupy their minds during the day to prevent boredom.  We were very happy to see that all the training is done on a positive reinforcement basis.  Interestingly, this training program doesn't just extend to the marine mammals, but also includes one invertebrate, namely a giant octopus.  For example, they have trained him to crawl into a bucket for when they need to move him out of his tank.  The octopus at the aquarium lives in a tank with rock-covered walls and with several notable places to hide.  This is fine with the octopus, but it doesn't make for a very exciting exhibit when the animal is almost always tucked away out of sight.  One spot at the bottom of the tank in particular seemed to be a favourite.  In an effort to keep the octopus out of there, the trainer placed three large (~20lbs) rocks in the way.  Not to be deterred, the octopus moved the rocks, crawled into his favourite spot, and made himself a nice rock wall so that he was now completely hidden!  It turned out that the best way to keep the octopus in view was to keep him occupied.  So the trainers began making little challenges for him to complete in order to get his food.  This includes putting a piece of fish in a plastic tube or a ball, or even in a closed jar.  Apparently the octopus changes colour to a mottled white and red when he completes the task, which they take to indicate a sense of contentment.  This is the same colour pattern he adopts when he is being petted by his trainer, who is very clearly his buddy.  Other trainers report that the octopus reacts differently when his buddy is in his tank versus when any other diver is in there.  




Part Two: The case of the missing crabs
    There's a famous story about a very crafty octopus that has been floating around the biology world for quite some time.  Lucky for us, we met the person who actually experienced it, and got to hear the story first-hand!  While working at an aquarium in California, a couple of young employees began noticing a strange disappearance of crabs from a tank in one part of a certain room.  What was especially strange was that all that could be found of the crabs were their legs -- no shells were anywhere in sight.  They didn't know who was doing this to the crabs, so one night they decided to camp out in the room and see what was going on.  To their amazement, they watched as the octopus in another tank reached up and grabbed onto an overhanging pipe, hoisted himself out of his tank, and swung like a monkey over to the crab tank.  Once there, he proceeded to pluck the legs off a crab and carry it back to his own tank.  He hid the legless (and therefore immobile, but still living) crab behind some of the rocks in his tank, and waited until later to eat it.  After eating the crab, he also hid the empty shell behind the rocks.  When the caretakers looked behind the rocks, they discovered years' worth of crab shells stockpiled in the hiding spot!