Octopus Cannibalism Caught on Video for First Time

Related Links

When octopuses go hunting for prey, they sometimes end up “dining” on members of their own species, and the cephalopods seem to have a taste for their victims’ arm tips.

Divers have captured video of this octopus-on-octopus action in the wild for the first time on video.

In a new study, researchers described three cases of cannibalism in the common octopus — Octopus vulgaris — recorded with a camcorder by scuba divers in Ría de Vigo, Spain, located on the northeastern Atlantic coast. In two of the cases, the predators had started to eat the tips of the arms of their prey by the time the divers found them. [See Images of the Cannibalistic Octopus]

And, in one of the cases, the predator had access to more “traditional” prey in the form of mussels, but it still chose to feed on another, smaller octopus.

Although scientists had been aware of cannibalism occurrences among members of O. vulgaris, the previously reported cases were known only from analyses of stomach contents and laboratory observations, the researchers wrote in the study published Sept. 8 in the Journal of Comparative Psychology.

However, “this behavior has never been described from direct observations in the wild by scuba diving,” said study author Jorge Hernández-Urcera of the Institute of Marine Research (IIM) in Vigo, Spain.

The researchers documented the first of the three cannibalism cases on Dec. 11, 2012, at a depth of 40 feet (12 meters), on a rocky bottom off the Cíes Islands, which are part of the National Park of the Atlantic Islands of Galicia (NAPAIG). A male octopus weighing about 4.85 pounds (2.2 kilograms) was holding in its grasp a smaller octopus without visible sexual characteristics, which weighed a bit less than a pound (about 400 grams). [See Video of the Cannibalistic Octopus in Action]

“The animal was dead, showing a pale white color and the tips of its arms had been eaten,” the researchers wrote.

The second case was recorded July 13, 2013, on a sandy bottom about 60 feet (18 m) below the surface near the Estelas Islands. A male octopus of about the same weight as the in first case carried an octopus weighing a bit more than a pound (540 grams) inside a ball-shaped sack that it had formed with its arms and web – the skin between its arms that it can spread to capture prey.

The diver who recorded the case realized that “the prey was still alive, because it poked and moved one of its arms between the dorsal pair of arms of the predator,” the researchers wrote. The diver disturbed the predator, which in turn let go of the prey, letting it escape, and therefore the researchers classified this case as “an attempted predation.”

Octopus Cannibalism Caught on Video for First Time