White-Spotted Octopus

Callistoctopus macropus, commonly referred to as the Atlantic white-spotted octopus, white-spotted octopus, grass octopus, or grass scuttle, is a species of octopus inhabiting the shallow waters of the Mediterranean Sea, as well as the warmer regions of both the eastern and western Atlantic Ocean, the 🌊 Caribbean Sea, and the Indo-Pacific area. This species primarily feeds on small organisms residing within the coral branches.

The mantle of Callistoctopus macropus can grow to a length of 20 cm (8 in), with its total body length reaching up to 150 cm (59 in). Notably, the first pair of arms can extend to approximately one meter, significantly longer than the other three pairs, and are interconnected by a shallow web. The octopus exhibits a striking red coloration adorned with white blotches on its body and paired white spots on its arms. In response to threats, its color intensifies—a display of deimatic behavior designed to intimidate potential predators.

Callistoctopus macropus forms a species complex across the Mediterranean Sea, the temperate and tropical Atlantic Ocean, the 🌊 Caribbean Sea, and is also present in the Pacific and 🌊 Indian Oceans. This species resides near the shore at depths of up to 17 m (56 ft), favoring habitats such as sand, rubble, or seagrass meadows, where it sometimes buries itself beneath the sand.

This octopus is more selective in its diet compared to the common octopus (Octopus vulgaris), with which it shares part of its range. While the common octopus feeds during the day, Callistoctopus macropus is nocturnal, seeking prey under the cover of night. Its feeding strategy involves moving between clusters of branching coral, often species like Acropora or Stylophora. The octopus envelops a coral head with its mantle and explores the branches with its arms, searching for small fish and invertebrates seeking refuge there. Remarkably, several groupers (family Serranidae) and other predatory fish are known to associate with the octopus during feeding, capitalizing on the small organisms disturbed from the coral by the octopus's activity.

Historically, the reproductive habits of this species were not well documented. However, observations have revealed that females attach short-stalked eggs, each measuring 4 by 1.2 mm (0.16 by 0.05 in), to a hard surface, creating a sheet of eggs. The female diligently tends to these eggs, providing aeration and keeping them clean. Notably, the female ceases to feed during this period and typically dies shortly after the eggs hatch, a common trait among octopus species. The resulting planktonic larvae, measuring approximately 5.5 mm (0.2 in) with short, seven-suckered arms, subsist on zooplankton, including crustacean larvae.