Tigers make extensive use of their vision for everyday functions and applications (in much the same way as human beings), but particularly for hunting during the darkness of night or the limited visibility of dusk or storms.
During the day, the tiger’s eyesight is more or less equal to the quality that we enjoy. Compared to many other animals, this is quite impressive.
However, tigers are not able to perceive the detail that we can, since this is not necessary for their purposes.
Also like humans, tigers have binocular vision. This enables them to be able to use their sense of depth perception to judge distances, giving their pouncing and jumping actions a distinct accuracy.
If they were not able to judge distances as well as they can, they could injure or lose their prey, rather than catching and killing it swiftly.
The eyes of the tiger are situated on the front of its head, and not to the sides. This helps with three-dimensional perception and depth perception, since both eyes look ahead.
Tigers hunt mainly during the evening and night times, when the vision of their prey is compromised. For this reason, their night time vision is excellent; about six times better than that of humans’. There are several adaptations within the actual eye that allow for this:
1.It has a wide, rounded pupil that allows maximum light to enter into the eye, when necessary.
2.The anterior chamber and lens of the eye are also larger for the same reason.
3.The tiger’s retinas comprise mainly rod receptors, which are cells that are sensitive to low light levels and can perceive very slight movements. There are some cone cells (colour receptors) in each eye, but these are used more for day vision, and not to perceive a range of different colours. In fact, it is thought that some tigers likely only see dull greens, blues and reds, while others see in black and white.
4.The tapetum lucidum is a layered, mirror-like structure behind the retina that reflects light back into the eye for a second time so that the eye and brain can form a brighter image of it.
5.There is a wide line of nerves running horizontally across the centre of the eye. This makes a huge difference to the peripheral vision capabilities of the tiger and allows them to be aware of approaching dangers as well as of prey that may be slightly out of their immediate field of sight.
The nictitating membrane is present in tigers in addition to top and bottom eyelids. This membrane can sweep across the eye, keeping it clean and moist.
In a life dominated by necessity, the tiger’s sense of sight is an essential part of its very survival.