Scientists have discovered why big cats like leopards and tigers have stripes and spots.
A team from the University of Bristol examined more than 30 different species of big cats looking carefully at their fur.
After studying where an animal lived, where it hunted and how it behaved, the scientists saw some common themes.
Cats that lived in forests were more likely to have a complicated pattern on their fur to help with camouflage.
But cats that hunted in the open, like pumas and cougars, were unlikely to have any patterns on their fur.
The scientists believe that the patterns and markings have developed over thousands of years as the animals adapted to their surroundings.
There is still one mystery that they can't explain; why more forest cats don't have stripes like a tiger.