How do animals see the world?

Both dogs and cats are more sensitive to light than us, which means they can see better when it’s dark. Cats are see particularly well in low light or semi-darkness compared to humans for three reasons:

1. A cat's pupil is several times bigger than ours (relative to the size of the whole eyeball). Being able to see relies on light, so it makes sense that the more light that reaches light detectors in the retina at the back of your eye, the more you can see.
2. The light detectors at the back of our eyes are called rods and cones. Rods help us see in low light, while cones help us detect colour. Cats also have rods and cones, but they have more rod cells which make them better at seeing in low light. 
3. Cats also have an extra 'mirror layer' at the back of their eyes, behind the retina. This means that if light hasn't hit a rod cell, it will reflect off the mirror and bounce back, giving the rods a better chance of detecting light. We don’t have this mirror, so if light from an object doesn’t hit a rod on the first try, we don’t see it.

Bonus fact

Cats can see in colour, but because they have fewer cone cells than humans they can't tell the difference between similar shades.

Dogs, on the other hand, have vision similar to humans who are red-green color-blind. Have you heard the ticks and clicks made by a traffic light? This is important for guide dogs, because they are unable to tell the difference between a red and green light based on colour alone.