Japanese researchers put cameras on the backs of adorable Adelie penguins and sent them out to hunt. Generally, if you are interested in continuing to think an omnivorous animal is cute, you don’t want to do this, and these penguins are no exception. It turns out they are ruthless, efficient killers.

I mean, the penguins just eat krill. But, as Reuters reports, they murder these tiny crustaceans with heartless speed:

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“The krill wiggle their bodies about, they clearly make an attempt to swim off at full speed and escape,” Watanabe said of his findings, published in the U.S.-based Proceedings of the National Academy of Sciences this week.

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“But that doesn’t make the slightest difference to the penguins. They just gobble up the krill that are trying to get away and swallow them whole.”

In the past researchers thought that perhaps penguins ate krill almost accidentally, as they hunted other prey. But no. These cute little penguins go after the tiny, defenseless krill one after another after another. “The krill killing-rate was both fast and efficient,” Reuters writes. “The penguins gobbled an average of two krill per second.” So much for adorable cuddly wuddly penguins. Hey, maybe we should put a camera on that kitten!