If you look very closely at a map of the London Underground you might see them.
There, peeking through the grid is the Caledonian Road reindeer. Blink and you'll miss the wombat waddling through Earls Court. And making a stately progress to the east is Mudchute the snail.
These are the animals of the London Underground and they are the rather lovely discovery of Paul Middlewick, back in 1988.
The first animal to make the list was the elephant of Elephant and Castle and more creatures are being discovered all the time... which ones have you spotted?