Octopus & Squid

Cuddly creatures with more than two arms

A spear squid.
A spear squid.

Birthdate Determines Mating Strategy for Spear Squid

Scientists from the University of Tokyo have discovered that a male spear squid’s birthday is not just a date—rather, it determines their mating strategy for the rest of their lives. 

According to their study, spear squid that are born early in the mating season (between early April and mid-July) grow to formidable sizes. Called “consorts“, they actively fight off any rivals in order to mate and then stick close to their mate as she lays her eggs. 

Mimic octopus in Mozambique

First-ever sighting of mimic octopus in Mozambique

Unlike any other member of its species, the mimic octopus excels in the art of disguise. It possesses the remarkable capability to alter its shape, hue, and behavior to resemble various marine organisms, including lionfish, flatfish, sea snakes, and more. This extraordinary talent serves not only as a spectacle but also as a survival strategy, aiding the octopus in confounding predators and capturing prey.

Ryukyuan Pygmy Squid, photographed in the wild.

Meet two new species of pygmy squid

The deep, emerald waters surrounding Japan's Okinawa Islands are a haven for marine life, and is one of the most biodiverse ecosystems on the planet. Within this vast biodiverse haven, scientists have discovered two new species of pygmy squid lurking beneath the surface: the Ryukyuan Pygmy Squid and Hannan's Pygmy Squid.

These two species have now been described and catalogued, with names that connect them to Japan's cultural heritage. Findings have been published in the Marine Biology journal. 

Researchers found Muusoctopus nursery grounds on a low-temperature hydrothermal vent off the shore of Costa Rica. The octopuses hang on to the rocks in inverted positions in order to protect their eggs.

Octopus nursery discovered in Costa Rica

The team, aboard the Schmidt Ocean Institute's research vessel Falkor, located the nursery nearly 2,800 meters below the ocean's surface. The expedition's footage, captured by the underwater robot ROV SuBastian, showcased breathtaking marine life, including octopus hatchlings, tripod fish, and vibrant coral gardens.

Cuttlefish are capable of changing colour and pattern (including the polarization of the reflected light as well as the texture of the skin.

Cuttlefish can go into electric stealth mode

Sharks home in on faint bioelectric fields generated by the bodies of their prey which they pick up using sensitive detectors on their snouts.

When researchers from Duke University showed captive cuttlefish held in tank videos depicting the menacing silhouettes of a shark or predatory grouper fish they reacted by lowering the electric field dramatically. Being shown the shadow of a harmless crab produced no reaction.

Octopuses observed throwing silt, shells and algae around and at other octopuses

In 2015 and 2016, researchers observed and filmed instances in which gloomy octopuses (Octopus tetricus) in Jervis Bay, Australia threw debris around themselves and sometimes at other octopuses.

This was the first time such throwing behavior has been observed in octopuses.

What was going on? Were these intelligent creatures merely rough-housing or having a pillow fight?

Led by Peter Godfrey-Smith at the University of Sydney, the researchers analyzed 24 hours of footage and identified 102 instances of such behavior amongst a group of about 10 octopuses.

Giant Pacific Octopus - photo by Andrey Bizyukin
Giant Pacific Octopus interact with divers

Do octopuses have an emotional life?

Octopuses have intrigued scientists for years, because they have both long- and short-term memory, they remember solutions to problems, and they can go on to solve the same or similar problems. They have been known to climb aboard fishing boats and open holds in search of crabs. They can figure out mazes, open jars, and break out of their aquariums in search of food.

The 12cm (4.72inch) fossil that caught the eye of palaeontologist Christopher Whalen.
The 12cm (4.72inch) fossil that caught the eye of palaeontologist Christopher Whalen.

Overlooked fossil turns out to be oldest known ancestor of octopuses

Found in Montana’s Bear Gulch limestone formation, the unassuming 12cm (4.72inch) fossil was subsequently donated to the Royal Ontario Museum in 1988. And there it lay quietly in a drawer in the Invertebrate Palaeontology collection for decades while scientists fussed over fossil sharks and other creatures from the site.

Until, one day, palaeontologists noticed the fossil’s 10 limbs and took a closer look.

Octopus at Curacao
Octopus on reef, Curacao

Octopuses’ arms can detect light

In general, the cephalopod’s sense of where its body is in space is quite poor, so this complex instinctive behavior may act to protect the arms from undetected predators nearby, which may mistake the tips of the octopus’s arms as fish or worms.

That octopus arms react to light has long been known. Its skin is covered in chromatophores, pigment-filled organs that change color when light falls upon them. They are behind the octopus’s color-changing camouflage ability.