Greater freshwater octopus

The greater fresh water octopus (Fluviatilis magna), is a large freshwater cephalopod belonging to the genus Fluviatilis.

Description

The greater fresh water octopus is a large species of freshwater octopus. It is found in the lakes, rivers and ponds of Frésir, and Boemont. Adults weight around 56 kg (125 lb.), with an arm span up to 6 m (20 ft.).

Ecology

Habitat

Greater fresh water octopuses usually live a solitary lifestyle, or live in communal grounds where multiple small dens house usually one octopus, although many times if the den is big enough it may house more. Communal grounds generally house up to 10-30 octopuses, the largest communal ground is the grounds at Etterport conservatory swamp and bog, with the grounds reaching a area of around 600 meters and a population of about 320. The most common place for communal grounds is in patches of emergent or submerged plants. Octopuses in the communal grounds normally defend the area by swarming, then killing any predator that seek to hunt in the area.

Diet

The greater fresh water octopus hunts clam, crayfish, fish, shrimp, snail, and, although rarely, birds.

Predators

The main predators of the greater fresh water octopus are river otters, sharks, and dolphins, while many other species are known to eat the eggs of the octopuses. Many birds of prey are known to hunt juvenile greater fresh water octopus, even though they are known to hunt in packs. If the bird takes too long to catch it's prey or struggles to catch it in time it is usually drown and eaten by the other members of the pack.

Land Adaptation

Due to the octopuses ability to perfuse oxygen through their skin, they can roam above water for about 2 hours. They walk with their section cups to propel themselves.

Size

Greater fresh water octopus is the largest species of octopus, the largest weighed about 341 kg (310 lb.), with the arm span up to 8.7 m (28.5 ft.). Below is a table of the largest octopus sizes that have been caught.

Date	Location	Length	Weight
2003-04-15	Burnsley, Betrunee, Frésir	11 m (36 ft.)	340 kg (751 lb.)
1932-11-14	Marilogne, Toutoise, Frésir	10.4 m (34.1 ft.)	308 kg (681 lb.)
1997-02-28	Etterport, Charac, Frésir	9.9 m (32.4 ft.)	285 kg (628 lb.)
1944-06-14	Pusart, Roussion, Boemont	9.6 m (31.4 ft.)	269 kg (593lb.)
1941-11-12	Valenteaux, Périzon, Frésir	9.1 m (29.8 ft.)	222 kg (489 lb.)
1958-12-18	Etterport, Charac, Frésir	8.8 m (28.8 ft.)	198 kg (436 lb.)
1986-12-22	Etterport, Charac, Frésir	8.7 m (28.5 ft.)	187 kg (412 lb.)
1937-07-28	Clonashel, Charac, Frésir	8.4 m (27.5 ft.)	175 kg (385 lb.)

Lifespan and reproduction

The greater fresh water octopus has the longest lifespan of any freshwater octopus, with typically 8–10 years in the wild. Males and females meet at breeding grounds or communal grounds once a year, usually in calmer waters, such as a lake or pond. If the octopus is communal then the female normally stays by the eggs watching over them. If the octopus is solitary then it watches over the eggs never leaving to feed, this usually results in the mothers death after the eggs hatch.

Greater fresh water octopuses live in two life styles, solitary and communal. While the solitary lifestyle is closer to how marine octopuses live, they hatch, and then travel on their own hunting, once a year they travel to breeding grounds, where they mate. The communal lifestyle is much more social with the octopus staying in a den protecting by other octopuses. They mate in the communal ground rather then a breeding ground. The is no correlation to which lifestyle is chosen by the octopus, with many solitary octopuses coming from communal grounds, and many communal octopuses coming from breeding grounds.

In the solitary lifestyle older males generally move to communal ground in their final years, commonly helping to look after eggs, and the juvenile.

Mutually beneficial relationships

Frésirian beavers

Although rare, the greater fresh water octopus is known to move in to small holes in the underwater part of a beaver dam, making small communal areas. The octopuses then help to upkeep the underwater part of the dam, while the beaver tends to the above water part.

Stripped claw crabs

Many communal grounds are known to house yellow stripped claw crabs or green stripped claw crabs. The crabs protect the octopus eggs from predators while the male octopuses hunt, and the female octopuses take care of the eggs, in return the crab is kept safe from predators.

Wosteaquean alligators

Also rare, female Wosteaquean alligators have been known to rest in communal grounds chasing away larger river sharks and dolphins while her young stay by the communal ground for protection.

Intelligence

Brain Function

The octopuses brain has three distinct lobes (a distinct characteristic of complexity), and they have about 800 million neurons. This is split between a main brain, and eight nerve cords each located in it's appendages. They have the largest highest brain-to-body mass ratio of any invertebrate.

Drug Use

While the greater fresh water octopus is known to live in emergent or submerged plants, some of these plants have certain chemicals that effect octopuses, namely Short barbed kraten (Barb Parvus), and Long barbed karten (Barb magnum). Greater fresh water octopuses have been observed to dig them out of the ground, and rip the roots out of the plant. They then gather them, and put them above water, the plant then dries, the drying process take 4-5 day after which certain chemicals break down into proto ecstasy like drug. The octopuses then emerge from the water and eat the substance. The chemical makes the octopuses more social, and more friendly towards others of the same species. It is thought this is how communal grounds first started to form, with it know a natural process that happen even with the chemicals available.

Tool & Structure Use

While octopuses are generally intelligent, the greater fresh water octopus is known to be very intelligent using rocks to crack open sea shells, and even throwing small pebbles to knock snails, and large insect into the water to eat them. They have also been observed to pick up small items (coins, jewelry, keys, and other shiny objects). These items are then held usually in the den the octopus is occupying, although there have been occurrences where the collection of items are held out in the open, usually in a circular trench surrounding the eggs, or on rare occasions the items are put in a mound in the middle, while the trench is filled with eggs.

The greater fresh water octopus has two types of dens, natural and built. Natural dens consist of rock crawl spaces or drift wood, while built dens are holes dug in the soil or cobbled together debris. Eggs in communal grounds are normally protected with rocks and sticks gathered from the surrounded area.