There have lots of stories about unexpected things turning up in toilets, such as snakes, frogs, and even squirrels and possums. And rats, of course.

So how easy would it be for a rat to make its way through the sewers, successfully traverse your internal plumbing, navigate the U-bend and find its way into your toilet?

Well according to National Geographic, pretty darn easy. Did you know that rats can tread water for up to three days, and even hold their breath for three minutes? Combine those skills with the ability to squeeze through the smallest of spaces and the chance of finding a rat in your home may not be so slim after all.

Check out National Geographic's video below: