Cuddly creatures with more than two arms
Cuddly creatures with more than two arms
The vampire squid (Vampyroteuthis infernalis) is a small, deep-sea cephalopod found throughout the temperate and tropical oceans of the world. It's easy to imagine the vampire squid as a nightmarish predator. It lurks in the eternal midnight of the deep sea, has a dark red body, huge blue eyes, and a cloak-like web that stretches between its eight arms.
To diagnose gum disease, dentists insert a thin metal probe between the tooth and gum to measure the amount of gum that has shrunk back from the tooth. The depth to which the tool can be inserted indicates the severity of the gum disease.
Apart from being invasive and uncomfortable, this method of diagnosis is sometimes painful for the patient. In addition, the measurements are viable, as the probe can measure only one portion of the tooth at a time.
Enter Jesse Jokerst.
The giant Australian cuttlefish (Sepia apama) is the largest cuttlefish in the world, reaching up to half a metre in total length and weighing in at around 11kg. Solitary animals, they are found all along the coastline of the southern half of Australia—from Central Queensland on the eastern coast, right around the bottom of the continent and up to Ningaloo Reef in Western Australia.
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 a 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.
Look up a chambered nautilus in a book or on the web will reveal they are in the same class of mollusks as octopuses, squid and cuttlefish. The first thing that sets this cephalopod apart from the rest of the group is that the nautilus date back more than 500 million years, and were once the dominant form of life in the ocean. And to share a night dive with one of these true living fossils is a very fortunate event.
Researchers from Jerusalem’s Hebrew University have filmed crawling octopuses to learn how the animals utilized their flexible arms when they move. Until now, scientists have struggled to understand how their elaborate crawling movements are coordinated. The answer proved remarkably simple: they just choose which arm to use to push themselves along without a trace of rhythm.
The rather dark reputation of Humboldt squid has been readily reinforced by various wildlife television programs and other media which present these creatures as giant animals hungry for blood or ruthless monsters, uncompromisingly attacking their prey.
My first experience diving with mating squid was in September of 2000 during a rare late summer event off La Jolla Shores of San Diego in the U.S. state of California. To date, it still ranks as one of my all time favorite dives.
One of Australia’s most unique underwater events is facing a new challenge. The Australian giant cuttlefish mating aggregation—the world’s only large-scale cuttlefish gathering—has seen the first major decline in numbers since the event was protected from commercial fishing nearly 14 years ago.
Cuttlefish and their colorblind cousins, squid and octopus, see aspects of light, including polarized light, that are invisible to humans
Cephalopods are sensitive to the linear polarization characteristics of light. To examine if this polarization sensitivity plays a role in the predatory behaviour of cuttlefish, scientists from the University of Bristol examined the preference of cuttlefish Sepia officinalis when presented with fish whose polarization reflection was greatly reduced versus fish whose polarization reflection was not affected.
Sulawesi is one of those places on nearly every diver’s bucket list. If not, it ought to be. A dozen years ago, people would have thought you daft to go diving there, much less build a dive resort in an area dominated by dark volcanic sand. Yet in Sulawesi there are nearly two dozen resorts vying for divers’ dollars, yen and euros.
