Sloths: how did two different animals wind up looking so similar?

Sloths and guppies appear to have little in common – one is an arboreal mammal living in the slow lane, while the other is a tiny tropical fish with a frantic existence. Yet both could hold the key to better understanding ...

When is a croc not a croc? When it's a thoracosaur

The fearsome Thoracosaurus, a dinosaur-era reptile from North America with jaws like giant pincers, bears an uncanny resemblance to a modern fish-eating croc called a gharial.

Proteins with different evolutionary histories now do the same job

Mitochondria are essential organelles of cells with a nucleus – known as eukaryotic cells. These are the cells which make up fungi, plants, and animals including humans. Mitochondria work like tiny power plants, processing ...

Tasmanian tiger doomed long before humans came along

The Tasmanian tiger was doomed long before humans began hunting the enigmatic marsupial, scientists said Tuesday, with DNA sequencing showing it was in poor genetic health for thousands of years before its extinction.

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