The giant Australian cuttlefish spends a lot of time resting, allowing it to channel more energy into growth, which has been dubbed the ‘live-fast-die-young cephalopod philosophy’ (9). Like all cephalopods, the giant Australian cuttlefish is an active predator, using its excellent camouflage to stalk fishes, crabs and other crustaceans (3) (4).
Thousands of individual giant Australian cuttlefish aggregate every winter to spawn, peaking in May to June, with the number of males outnumbering the females by up to 11:1 (2)
[ (4)]. During courtship, the male will perform spectacular displays to attract a female, in which bands of colour pass rapidly along the body (4). Males tend to establish [territories] around the best egg laying sites (3). As larger, aggressive males will often guard females entering their territory, small males, known as ‘sneaker males’, may adopt female colourings to avoid the larger males and achieve a mating (4).
The eggs of the giant Australian cuttlefish are lemon-shaped. Laid in crevices, the eggs hatch after 3 to 5 months (4).
The mantle cavity, a feature common to all molluscs, has adapted to help the giant Australian cuttlefish avoid predation. Water can be rapidly sucked in and ejected from the mantle, and is directed using a moveable ‘funnel’ to create a form of ‘jet propulsion’ which enables the giant Australian cuttlefish to swiftly escape from predators (10). Like many species of squid and octopus, the giant Australian cuttlefish is also able to protect itself by squirting ink, which obstructs the predators view or acts as a diversion. There is also evidence that the ink may block the scent of the cuttlefish, thereby providing protection from predators which hunt by smell (6).
Most species of cuttlefish are able to quickly change the colour and texture of the skin, allowing them to adopt similar shapes, colours and textures to the surrounding environment, such as rocks on the sea-bed. This is also the same technique employed when achieving sneaky matings or luring in prey (11).