More than 1 million penguins who’ve been hiding in a remote part of Antarctica were recently discovered thanks to images taken from space and … their own poop.

A study in the Scientific Reports journal reveals the Danger Islands find of more than 750,000 pairs of Adélie penguins—a discovery researchers are calling a “total surprise,” per the BBC.

Scientists find huge, secret colony of penguins | WGN-TV

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