The Lion’s Eyes
Colour & Size
When born, the eyes of lion cubs are closed, as they are not yet fully developed. Lion cubs gradually open their eyes in the few days after birth, with these being completely open within 2 weeks. Although the eyes are initially of a blue-grey colour, this will change to amber after 2-3 months, staying so for the rest of their lives.
The eyes of lions are quite large - so much so that they can’t move their eyes side to side very well, and actually need to move their whole head to look in another direction!
The pupils of lions are large and round. Round pupils capture more light than slit pupils, which improve focus but at the cost of lesser overall vision. For this reason, slit pupils are mainly seen in small ambush predators, such as serval or the genet, while larger carnivores will exhibit round pupils. Most prey species, on the other hand, have rectangular pupils, giving them panoramic vision and allowing them to look out for danger from almost all directions.
Lion: round (contracted) pupil. Genet: Slit (dilated) pupil. Wildebeest: rectangular pupil.
In low-light conditions, the pupil dilates so more light can reach the retina, and improve night vision. Retinas are made up of rod cells and cone cells: the rod cells aid the reflection of more light into the eye, while cone cells are for colour vision. When compared to humans, lions have significantly more rod cells than cone cells (25:1 versus 4:1), resulting in their impressive nocturnal vision and allowing them to see 6 to 8 times better than humans in low light conditions.
Like most nocturnal animals, lions have something inside their eye known as 'tapetum lucidum'. This is a reflective layer of cells behind the retina, which acts as a mirror and gives the rod cells a second chance to absorb light waves. This almost doubles the effectiveness of their night vision, as is the reason for the eerie ‘eye shine’ that you see when you shine a light on animals at night!
To help reflect even more light back into the eye, lions have a white patch of fur below their eyes. This feature is a good indication that lions are nocturnal: if you look at a cheetah, you will notice they instead have black tear-like markings. This reduces glare, which is ideal as cheetahs tend to hunt during daylight.
Eye shine is a result of the reflective layer behind their eyes, known as tapetum lucidum.
White patch of fur below her eyes aids better night vision.
Cone cells in the retina are responsible for colour vision. As we have learned above, lions have fewer cone cells than humans, meaning their colour vision is impaired. Although they can distinguish between blues and greens, they cannot see shades of red. In humans we call this Protanopia (aka red-blind), and it looks like this:
Location of the eyes
Finally, the location of the eyes will also vary depending on how animals use these. Like all predators, lions have eyes pointing forward, to facilitate binocular vision. This means that there is greater overlap of the field of view of both eyes, allowing them to judge depth more effectively. This is extremely important when stalking and hunting prey. Prey species, on the other hand, have eyes on the side, therefore maximising field of vision - essential if you’re trying to not be snuck up on and eaten!
Keeping animals wild should be prioritised over keeping them safe
The Pride Lion Conservation Alliance was founded in 2015 by six women working in lion conservation – including our Joint CEOs – with the goal of creating a new, collaborative approach to lion conservation. The Pride Alliance recently published an essay on Mongabay arguing that conservation efforts should prioritise keeping populations and areas wild, rather than keeping individual animals safe.
The urge to intervene and treat injured lions, and perhaps even scoop up their cubs to keep them safe at rescue centres, is of course deeply human. But when we take these actions, these animals' lives are often degraded and endangered. While in some cases intervention is unavoidable and warranted – such as treating animals injured through human impacts, such as snares or poison – intervening to treat injuries obtained through natural causes goes against the essence of wilderness embodied in these animals.
Instead of bowing to uninformed social pressure, we should strive for more considered discussions of these issues which embrace their complexity and nuance. Only then will we be able to find solutions that balance the need to protect these inspiring wild animals with the rights, views, and needs of local people.