The Octopus tetricus, more commonly called the Sydney Octopus (or Common Octopus, or Gloomy Octopus) is one of the most interesting creatures in Sydney from the family Octopodidae. They are curious, intelligent and sometimes even playful. They can also be fiercely protective and strong as a man.
Octopus are easily my favourites underwater. When I lived in the UK I would only dream about seeing them on a dive, but living in Sydney means I get to see them on almost every dive both in the harbour, in the shallows and out at sea!
Fun facts about octopus:
They taste with their tentacles
They can change both colour and shape, which has been recorded at over 150 times within a minute
They are usually white when relaxed or aged and red when active or playful
They have three hearts
They have a beak like a parrot
Their brain is not in the big bulb behind their eyes where you would expect, but instead is spread around their throat with more than half of their brain neurons in the arms
They have a dominant eye, and the ability to move each eye independently of each other and have panoramic vision
They usually only live 3 or 4 years, and mate just once (they die shortly after their eggs hatching, and the males die soon after mating)