Having a pet is getting to know their personality and all their quirks, feeling like you can communicate despite not really sharing a language at all. But have you ever thought about how your beloved cat, dog or bird sees you, your house and all the fancy toys you've bought for it to play with? Here's how your pets see the world.
Dogs
We all know this one: dogs see in black and white, right? No, actually: as it turns out, dogs do actually see colour, though they see less colour than humans do.
Eyes contain two types of photoreceptors, called rods and cones. Cones are responsible for seeing colours, while rods help vision in low light. While humans have three cones for red, green and blue vision, dogs only have two, which are suspected to be green and blue.
This means dogs will be able to see some colours vividly, but others in a vastly different way to how humans do. It's suspected that dogs are also able to see more shades of grey than humans do, and also have far superior night vision to ours - which is why their eyes reflect light in the dark.
You can see a mock up of how dogs see in this video:
Cats
Cats are very similar to dogs in that they only have two cones, likely also green and blue. They also have far superior night vision, as most people would know.
Cats also have a wider field of view than humans, though the amount of it that's in focus is about the same. Cats are more short-sighted than humans, but they make up for it with increased acuity in other senses.
Birds
Unlike dogs or cats, birds actually have better vision than humans. As well as red, green and blue photoreceptors they have a fourth that allows them to see on the ultraviolet spectrum. This means that birds can see a whole range of colours we don't even know about.
What's even more amazing is that birds have a special protein in their eyes that helps them 'see' the Earth's magnetic rays, aiding migration and homing behaviours.
As animals that rely on their eyesight more than most, it's no surprise that birds have evolved a whole lot of impressive visual tricks.
Check out an explanation here:
Snakes
As a pet I have always wanted to have, I'm pretty curious about how snakes see - though there isn't as much research on them as on other animals.
Snakes also appear to be dichromatic like cats and dogs, seeing in blue and green. Vision seems to be different between nocturnal and diurnal snakes, with diurnal snakes boasting a UV filter that's a bit like a built-in pair of sunglasses.
Most interesting though is snakes' ability to see infrared - though technically this isn't vision but another sense provided by a pair of 'pit organs' on the snake's head. This allows snakes to hunt even in total darkness, as demonstrated in the video below:
This story on the vision of your pets has been updated since its original publication.