Hi guys it’s Issue #6 of Impurest Cheese’s Guide to Animals. Last week the Venezuelan Pebble Toad proved it was ready to rock and roll in it’s time in the spotlight. This week’s animal is smart, beautiful and deadly. Hope you guys enjoy.

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Issue #6 – Blanket Octopus

Kingdom – Animalia

Phylum – Mollusca

Class – Cephalopoda

Order – Octopoda

Family – Tremoctopodidae

Genus – Tremoctopus

Species – gracilus

Related Species - There are four members of the genus Tremoctopus. They are more closely related to the Paper Nautiloids or Argonauts than other types of Octopus (1)

Range - The Blanket Octopus is a pelagic species and has been found in tropical and subtropical waters of the Atlantic, Indian and Pacific Oceans

The Ocean’s Dark Knight

The Blanket Octopuses most distinct feature is the two elongates arms and the massive length of webbing stretched in between them. However it is only the females that have this feature and the species practices one of the most extreme cases of sexual dimorphism in the animal kingdom. At almost two meters long the females are one hundred times the size of the inch long males which remain in a pseudo-larval state (2). Both sexes are pelagic, unlike most sea bed dwelling octopuses and can be found in the open ocean close to the surface.

Like all cephalopods the Blanket Octopus is carnivorous presumably feeding on fish rather than molluscs and crustaceans like its bottom dwelling relatives. However being large, soft bodied and out in the open the species is prey to a wide range of predators and as such have evolved two fascinating defensive mechanisms to stay off the menu. First defence for the female Blanket Octopus is to extend its webbing (in the same way Batman holds his cape wide) to trick predators into thinking they are larger than they really are. If that fails the Blanket Octopus deploys a second, potentially deadly weapon. While in its larval state the Blanket Octopus rips the stinging tentacles off of the Portuguese Man ‘O’ War (Physalia physalis), to which it’s immune to, and uses them as offensive and defensive weapons against both predator and prey (3).

Despite the size difference the male Blanket Octopus has no problem when courting the female. Like all Octopuses he has an arm called the Hectocotylus to transfer sperm over to the female. After that to protect his investment he will then snap off the arm to continue fertilising the female before dying shortly afterwards. Like most cephalopods the female will then guard her eggs, laid on the seafloor, fiercely until they hatch with her dying from exhaustion after her vigil ends

Five Fun Blanket Octopus Facts

The female Blanket Octopus can sometimes have as many as one hundred male Hectocotylus fertilize her eggs at any one time.

The male Blanket Octopus has long been one of the ocean’s great mysteries. While the female was first described in the 1800s, the male was first seen alive as recently as 2002

If their deadly arsenal of defensive tricks fails the Blanket Octopus has one more trick up its sleeve. Like it’s relatives it practices Autonomy (willingly severing body parts) and can drop parts of it’s webbing to lead predators away.

The Blanket Octopus isn't the only cephalopod to use tools for hunting and defence. The Coconut Octopus (Amphioctopus marginatus) gathers up coconut shells and uses them as a mobile hunting shelter to defend itself from predators.

Despite the long ongoing argument the plural of Octopus is now considered Octopuses and not Octopi

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Bibliography

(1) – www.arkive.org

(2) - http://blogs.scientificamerican.com/octopus-chronicles/2013/04/05/unusual-offshore-octopods-the-weapon-wielding-blanket-octopus-video/

(3) - http://thediveshack.blogspot.co.uk/2012/10/creature-feature-blanket-octopus.html

(4) - http://tolweb.org/accessory/Tremoctopus_Eggs,_etc.?acc_id=2416

Picture References

[1] - http://creepyanimals.com/wordpress/wp-content/uploads/2011/01/blanket-octopus-veil.jpg

[2] - http://ferrebeekeeper.files.wordpress.com/2012/08/blanket_octopus_by_ccris393-d3jmhh2.jpg

[3] - http://reefbuilders.com/files/2011/05/blanket-octopus.jpg

Hope you guys enjoyed the insight into this deadly predator. Drop me a comment with an animal you want explored in the next issue. Just a word of warning though, next week’s animal is a spider (anyone wishing not to be included in the shout-out should let me know so I can avoid arachnophobia issues)