4 eyes of the tiger
The majestic tiger, whether it be the Sumatran, Siberian or Bengal tiger, they are very well known for their ferocity and beauty. In particular, their unique stripes have earned the big cat an iconic status amongst exotic animals, becoming a real favourite across zoo visitors and school children learning about the natural world. The characteristic stripes not only help to win over our hearts, but serve an ecological function, camouflaging the predator from the prey that they hunt through the tall grass. To us, a bright orange cat may not be so low key but considering most of their prey species see in monochrome colours, the pattern acts as an effective core element of their hunting strategy.
Now you may have known all about the tiger’s stripes, but I had to set up this next feature somehow. So when visiting the zoo recently to help a friend out with his dissertation project, I took my camera down to the tiger enclosure and took the photo you can see below. The defining feature glaring me in the face was not only the stripes, it wasn’t the first time I had seen a tiger, it was actually these two bright circles, one covering each ear with a piercing white fur. I thought to myself, how have I never noticed this before, these guys are one of my favourite animals! I guess the stripes usually take the spotlight, drawing attention away from the tiger’s multi-pattern aesthetic.
So we know the stripes serve an evolutionary function, some kind of purpose that helps the tiger, but what about these ear spots?
There are a number of theorized functions for the secondary pattern, one such idea suggests that the ear spots are designed to mimic eyes, a commonly adopted use for different patterns and colourisations throughout the animal kingdom. Like that of certain butterflies, the ear spots could have been developed in such a way that strongly resembles larger eyes.
Having large eye illusions may serve to scare away other predators that would attack and pounce from behind, including other tigers that want to eliminate the opposition in their territory. Another possible use is to signal aggression, as a tiger that is threatened will rotate their ears to face the threat, providing a visual warning to others. It may communicate ‘Don’t mess with me’ or rather ‘look how big I am, don’t waste your time’.
One other possibility for the ear design is rooted in parental care, a well-developed feature for mammals such as the tiger. It is suggested that young cubs can find their mothers easier in tall grass thanks to the glaring white spots, given that the cubs will most likely be following behind their mum. With this being said, males also sport the ear spots so the usage isn’t overly supported.
Thanks for reading this insight into tiger evolutionary ecology, we've got a busy week but expect another blog around the same time next week!