I’m just going to put this out there: I think animal eyeballs are really cool! Each animal’s pupil shapes serve a meaningful purpose to suit their different functions and behaviors in wildlife. I actually mused about this on Tik-Tok a while back:
Eagle Eyes
You’ve probably all heard a person who’s good with attention to detail referred to as someone with “eagle eyes” and there’s a reason for that: Eagles—and also falcons—are largely agreed upon to have the best vision in the animal kingdom. Not far behind them on the list of great seers are: owls, cats, goats, dragonflies, chameleons, prosimians, various birds of prey and oddly enough, mantis shrimp (who knew?).
Each of these species rely heavily on their vision to identify predators, hunt for food and navigate their habitats safely.
Vertical Vessels
Animals such as smaller (domesticated) cats and foxes possess vertical slit pupils so they’re able to hunt close to the ground. That shape also provides them with an incredible depth perception so they can disseminate vertical objects like blades of grass and foliage more easily.
Horizontal for Horizons
Grazing animals like horses, goats and deer have horizontal pupils that can rotate to watch for predators even when their head is bent down to consume food. It essentially allows them to expand their perspective on horizons from a variety of natural positions.
Reptiles such as snakes and frogs also have horizontal pupils to give them a scope of vision that enables them to ward off predators.
Llamas and alpacas have a variation of this horizontal pupil shape, which can sometimes appear oval or wavy, because of the iridic granule detail. This helps protect the animals from bright light. Also to note: animals of various species have pupils that enlarge to allow the maximum amount of light in to see what they’re preying upon more clearly.
Crescent Like the Moon
Various marine life such as certain catfish, flatfish and stingrays have crescent pupils to decrease the effects of light distortion underwater. This shape also helps provide a higher resolution for objects viewed, provides a wide field of vision and enhances contrast at high spatial frequencies to help them determine what they’re swimming toward.
Beaded (Seriously)
The fanciest pupils can be found on geckos and other lizards and fish. This vertical beaded shape, which sometimes resembles a string of pearls, enables animals that are active both day and night, or simply nocturnal, to hunt in multiple environments and perceive distance. Like a magic trick, these pupils can reduce to very tiny vertical slits in the midst of bright locales.
Round — Like Us
Dogs, wolves, lions and other predators that hunt actively during the day have round pupils like us humans. This shape offers better depth perception, size and strength, but lacks the field of view afforded to those with other pupil shapes. The ‘pack’ nature of how these animals hunt as well as their advanced intelligence supplement the extra benefits that animals with vertical and horizontal shaped pupils enjoy.
What about bugs?
We’ve all gasped at a spider in horror at some point and watched it freeze as it realized it was discovered. You may think it must have some incredible pupils to be able to see and detect us so clearly, right? Wrong! Insects actually don’t even have pupils. Their eyes are compound, which means they’re made up of ommatidia (translation: photoreceptor units) that act as their cornea and lens , plus cells to transmit color and brightness. You may notice dark spots, known as ‘pseudo pupils’ on some, which is really just reflecting their eyes’ absorption of light.
The Star Pupil (Not Literally)
You know who I think has the absolute best animal eyes? Cuttlefish!
Their eyes are literally W-shaped in bright light! Why? It helps distribute light evenly in an uneven vertical light field and camouflage them as they make their way around the water. Their pupils dilate in the dark to let more light in, just like humans too. Mind-blowing!
I’m curious to know: What different eye shapes do you all see in the animals you like? Tell me about them in the comments section.
Photo credits: Eagle: A_Different_Perspective/Pixabay; Fox: Alexas_Fotos/Pixabay; Deer: Joshua Choate/Pixabay; Llama: Pezibear/Pixabay; Catfish: furbymama; Gecko: gayleenfroese2; Lion: Sponchia/Pixabay; Spider: User 631372/Pixabay; Cuttlefish: Naveen Manohar/Pixabay
