Octopus & Squid

Cuddly creatures with more than two arms

Octopuses Could Lose Eyesight if Ocean Temperatures Keep Rising

Heat stress brought about by rising temperatures may cause impaired eyesight and more deaths of pregnant mothers and their unborn young. 

In a study by the University of Adelaide, unborn octopuses and their mothers were exposed to three different temperatures: a control temperature of 19°C, 22°C to mimic current summer temperatures, and 25°C to match projected summer temperatures in 2100.

Negative impact on eyesight

Compared to the other two groups, octopuses that were exposed to 25°C produced significantly fewer of some proteins responsible for vision. 

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.

Through RNA editing, the cephalopods appear to have found a unique way of tweaking their own physiology to adapt to environmental temperature changes

Octopuses adjust to cold by editing their RNA

A recent study has unveiled a fascinating aspect of octopus biology: their ability to adapt to cold ocean temperatures by making precise edits to their RNA. 

RNA editing is a molecular process through which cells can modify nucleotide sequences in RNA, resulting in proteins that differ from those directly encoded by DNA. This ability is particularly enhanced in octopuses, who use it to fine-tune the functions of their nervous system at low temperatures.

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.