For decades, researchers have studied how certain animals evolved to be intelligent, among them apes, elephants, dolphins and some birds. But all the scientific theories fail when it comes to cephalopods, a group that includes octopuses, squid and cuttlefish.

Intelligence in animals comprises cognitive skills that help an animal thrive, such as using tools and storing food. They have bigger, more powerful brains, learn from others and tend to live for a long time.

Cephalopods behave in ways that suggest they’re highly intelligent. An octopus named Inky, for example, made a notorious escape from the National Aquarium of New Zealand, exiting his enclosure and slithering into a floor drain and, apparently, out to sea.

Cuttlefish can scare off predators by forming eyespots on their bodies in order to look like giant fish. Octopuses can figure out how to push and pull a morsel through a tiny hole in the wall of their tank. Cephalopods also have relatively big brains. But most die young and they seem to be loners.

Piero Amodio, a graduate student at the University of Cambridge, thinks the evolutionary history of cephalopods may explain this intelligence paradox. About half a billion years ago, their snaillike ancestors evolved to use their shells as a buoyancy device. They could load chambers in the shell with gas to float up and down in the ocean. A cousin of cephalopods, the nautilus, still lives this way.

These fish kept busy despite hurricane

On Aug. 25, 2017, Hurricane Harvey made landfall about 5 miles east of Rockport, Texas. The Category 4 storm had an eye wider than the length of Manhattan and a 10-foot storm surge. But amid this destruction, one thing seemed to weather the storm quite well — spotted sea trout, which were busy making babies as the eye of the hurricane passed over their spawning grounds.

“Their urge to reproduce, or that inclination, is so strong that not even a hurricane can stop them,” said Christopher Biggs, a graduate student at the University of Texas at Austin.

Biggs and his colleagues reported their discovery in Biology Letters. The resilience of these fish suggests that they and their relatives, popular for recreational fishing in the Gulf of Mexico, may cope surprisingly well with increases in human activity and other temporary disturbances.

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