Macroctopus

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Macroctopus maorum, commonly known as the Māori octopus or New Zealand octopus (wheke in Māori), is a very large, powerful octopus living around New Zealand and southern Australia. It is the largest member of the Macroctopus group and is known for being tough and aggressive.

Appearance and habitat
This octopus can have an arm span of more than 3 meters and can weigh up to about 12 kilograms. It is usually orange-brown or dark purple-grey, with many small iridescent white spots on the web, arms, and crown, but not on the mantle. It has long, uneven arms and can regrow lost ones. It lives on the seafloor in soft sediment and rubble from the shallow subtidal zone down to about 550 meters, often using shelters. Juveniles are sometimes found in intertidal rock pools.

Diet and hunting
Māori octopuses eat crabs, lobsters, scallops, other crustaceans, and fish. They hunt mainly at night and use a variety of techniques, including stealth, ambush, jet propulsion, and even digging to uncover prey. They can change color and texture to blend in and confuse prey. They inject prey with a toxin to help digest it.

Intelligence and behavior
They are solitary and build a den, often keeping a midden of shells and rocks at the entrance. They can display a range of behaviors when disturbed, such as posturing or defensive arm movements. Young octopuses may settle in tidal pools, while adults roam the deeper seafloor.

Life cycle and reproduction
Māori octopuses have a short life span. Males mate with females, usually in March and October, and often die soon after mating. Females lay thousands of eggs (about 7,000), in clusters attached to the substrate, and guard them without eating until they hatch. Eggs hatch into free-swimming planktonic larvae. The young have several suckers per arm and begin life much as the adults do, just smaller.

Predators and threats
Predators include fur seals, sea lions, pilot whales, other large octopuses, and some seabirds and penguins. In some areas, humans affect them through fishing bycatch, particularly in rock lobster fisheries.

Economic and scientific note
Māori octopuses can impact rock lobster fisheries as both predators and bycatch. Scientists have used these octopuses to study aging with stylet increment analysis, though aging them remains challenging.

In short, the Māori octopus is a large, nocturnal hunter of the New Zealand and southern Australian seas, notable for its size, camouflage, and complex life cycle.