You might be used to going through scanners at airports - but these special metal detectors are just for penguins!
The scanners are being used at London Zoo to detect tiny microchips beneath the animals' skin.
The microchips are like little identity tags, to show which penguin is which!
And it's not just penguins that are tagged. Almost all the animals at London Zoo have microchips, except the fish and small birds.
It helps the zoo keep track of all the creatures, like this slippery python, and would make it easier to find the animals if they ever escaped or were stolen.