Humans have evolved as social animals and we pick up on incredibly subtle non-verbal cues from each other. Unlike most other primates we have contrasty whites of our eyes (the sclera) which enable us to see where someone else is looking. We can also give them instructions on where they should be looking. We can literally point with our eyes, in complete silence, and with our hands full. That sounds incredibly useful if you’re co-operating. Having whites of your eyes also means you can roll your eyes, look to the heavens, be bashful and avoid someone’s gaze and give all manner of other subtle and not so subtle messages. When we couple eyeball movements with eyebrows humans have got a huge vocabulary without even moving our lips.
Seals, however social, are like many other mammals and rely on seeing where their fellow seals’ noses are pointing. Seals also have to see well in dim waters to catch their prey so they need large apertures in their irises to allow maximum light to enter. All that means that they have deep dark pools of eyes. To us they seem mysterious and unknowable; that’s just us anthropomorphising. Here’s a young seal rescued by Orkney Seal Rescue centre.
And just before you start rolling your eyes at this post, just remember, people can see you doing that.