The octopus: 11 freaky facts

Easily the most bizarre creature in the sea, the humble octopus is a cephalopod of many talents, with DNA like that of no other animal (described by one scientist as looking as though it had been rearranged in a blender). An octopus also holds the record for longest brood period of any creature, with one octo-mum tending her eggs for 4.5 years! Facts suggest there to be 289 recognised species of octopus, and all species have distinct characteristics, from the giant octopus, which can grow up to 9 metres across, to the Wolfi, the world’s smallest octopus, which measures only 1.5 centimetres and weighs less than a gram.

Here are 11 reasons why they are one of the ocean’s weirdest:

1. Octopuses have 3 hearts

They have 2 small hearts located close to each of their gills that enrich the blood with oxygen before transferring it to 1 larger heart, which then pumps it around the rest of the body.

2. Octopus blood is blue

Unlike our red, iron-based blood, octopus’ blood is blue because it is copper based, and more efficient at transferring oxygen around the body in the cold.

3. They have no skeleton

Meaning octopods are able to slip in and out of tiny holes no bigger than the neck of a beer bottle.

4. Octopuses love their gardens

Some octopuses will collect attractive things, and build their own unique garden around their lairs. It could be a fortress to defend, a way of attracting mates or pray, or just because it looks good.

5. They are quite the performers

To attract a female, the male will flash intricate skin displays. Males will normally die soon after mating while female octopuses will selflessly tend their eggs, and succumb to an in-built self-destruct mechanism that kicks in once the young have hatched.

6. They have a toxic weapon

They disorientate predators with dark, toxic ink that reduces visibility, interferes with the sense of smell and taste, and irritates the eyes.

7. A short life-span

Octopuses typically only live from one to five years.

8. Freakishly intelligent

Octopuses have the largest brain of any invertebrate, and 2/3 of all their neurons are actually in their tentacles. As a result they are excellent problem solvers, can learn to navigate mazes, unscrew jars, and use “tools”.

9. They have been around for a long time

The oldest-known octopus fossil is 296 million years old!

10. They are stronger than they look

Pacific octopus suckers are so strong that each one can lift a weight of almost 16 kg! The average octopus has eight arms with 240 suckers per arm. That’s about 1,920 suckers in total.

11. Masters of disguise

In a fraction of a second, octopuses can change the colour and texture of their skin to blend perfectly with their surroundings.

Written with Alice Grainger, this article featured in Scuba Diver AUSTRALASIA issue 7/2015, AA No.84 and on
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