Gold miners working in the Yukon regularly find ancient ground squirrel burrows throughout the permafrost, many containing fossilized feces. Researchers analyzing these well-preserved poop piles found they contain some of the oldest DNA ever recovered, dating from 30,000 to 700,000 years ago. Tucked inside were traces of a wide range of ancient animals, including woolly mammoths, grasshoppers, steppe bison, ancient horses, American cheetahs, as well as hundreds of plant species.

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• ‘Super-good, ice-making microbes’ may trigger snow and rain, or help freeze food
• We’re a hotbed of mutations, and scientists are leveraging that for our health
• Going out on a limb. Animals regrow body parts, maybe we can too
• From the archives: Isaac Asimov on human creativity and robots

150 years ago, Charles Darwin noticed that birds and humans were both drawn to bright plumage and elaborate display. He called this interspecies esthetic appreciation a “shared taste for the beautiful.” Now, in a recent study, an interdisciplinary team of scientists built an online game exploring the mating calls of 16 different species and discovered, to their surprise, that humans and animals agree on which sounds are more attractive.

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• How the brain can learn to truly multitask
• From the archives: The Russian space mirror that flashed across Canadian skies
• The Matrix is real: birds, dragonflies and dogs see the world in slow motion
• Could the next giant particle collider unlock the mysteries of the universe?

The newly described Tylosaurus rex was a violent bus-sized Komodo dragon-like creature with serrated teeth. Dubbed the ‘T. rex of the sea,’ it would have occupied the top of the food chain in the marine ecosystem over 80 million years ago.

PLUS:

• Pigeons use their livers to find their way home
• From the archives: How Jocelyn Bell Burnell discovered pulsars
• Scientists discover an underground network of lakes hidden under Arctic ice
• New book explores the million year history of how we sleep — and why we’re doing it wrong today