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Octopi and squids
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Mod
"Jervis Bay, off the coast of Australia, a site where large numbers of Sydney octopuses live.
In making more recordings and studying them carefully, the researchers were able to see that the female octopuses engaged in multiple types of object-throwing. In most instances, throwing material such as silt or even shells was simply a means of moving material that was in the way or when building a nest. Less often, they saw what were clearly attempts by females to hurl material at a nearby male—usually, one trying to mate with her.
The researchers found that the hurling was done by grabbing material such as rocks, silt or shells and holding them under the body. Then the material was placed over a siphon that the creature uses for pushing out a jet of water very quickly. Doing so propelled the material ahead of a jet of water, sometimes as far as several body lengths.
In studying the tape, the researchers found multiple instances of females targeting males. In one scenario, a female threw silt at a male individual 10 times. They also found that the males often tried to duck when objects were thrown at them, and were successful approximately half the time. They also noted that throws meant to get rid of material were performed differently than those aimed at another octopus, involving tossing between the two front tentacles; suitor-repelling projectiles were usually launched between the first and second tentacles. The researchers also witnessed one female toss a shell like a frisbee using one of her tentacles. Notably, they did not see any evidence of males retaliating by tossing things back at females who were targeting them."
More information: Peter Godfrey-Smith et al, In the Line of Fire: Debris Throwing by Wild Octopuses, biorxiv (2021). DOI: 10.1101/2021.08.18.456805
Mod
This thriller by a former fishing guide turned novelist, features a marine scientist and (among many other things) his observations of a captive octopus in Florida.
Randy Wayne White
These creatures are known to be intelligent and some species can change colour. They have been filmed walking with different gaits and using different numbers of legs along the sea floor.
The 'diablo' or Humboldt squid, a related mollusc, is red, and several have been reported latching on to a fisherman or diver as teamwork and pulling him into the depths. One diver reported this happening to him, and said he finally managed to break away, coming to the surface with a burst eardrum, at a considerable distance from his boat.
And the giant squid, Architeuthis dux, lives so deep that generally only the adult sperm whale can go in pursuit. This may have sparked the kraken legends as massive elongated specimens have washed ashore.
So, please post any news, books and stories about these fascinating creatures! We have shared some already in the thread about World Ocean Day.