Hamsters. Who can resist these cute, furry little rodents that make popular pets. There are 5 species of pet hamsters (including the popular Syrian hamster, and at least 18 species of wild hamsters.. While hamster owners might want to play with them all the time, hamsters are nocturnal animals that spend much of their daylight hours sleeping. This fact alone might lead you to think that they have great eyesight at night. But the truth about hamsters, and their senses, might surprise you.
Can hamsters see in the dark?
The easiest answer to this question is . . . sort of. You see, hamsters need some light to be able to see objects. They don’t have great eyesight in daylight. Adult hamsters can only see a few inches in front of their nose, although they do have a wide range for things near them. In other words, hamsters are nearsighted.
In bright light, they are practically blind. Actually, hamster babies are born blind. So, basically hamsters see best in dim light. In pure darkness, they can’t see very much. Since their eyesight is poor, they rely on their other senses, particularly smell, more. There oversized teeth and whiskers also help them make sense of the world.
Okay . . . there’s the basic answer, but lets look into hamster eyes with more detail to understand the bigger picture.
The eyes of hamsters
As mammals, hamster eyes function in ways similar to the eyes of humans. This breaks down to these steps:
- Light passes through the front surface of the eye (the cornea)
- It then goes through the round opening known as the pupil, which controls how much light gets in. The pupil expands in dark lighting, and becomes smaller in bright light.
- The light passes through the lens, which filters and bends the light to help focus
- The light continues through the gel-like vitreous fluid that fills your eye
- It hits the retina at the back of the eye, which translates the light energy into signals that travel along the optic nerve to your brain, which interprets the images received.
Cool and simple, right? Well, simple in the complex ways our bodies function.
How, then do hamsters eyes differ from humans? As nocturnal mammals, their eyes tend to be larger, with big pupils and a lot of surface to their retina. This allows more ambient light in. The nearly spherical eyes of hamsters come in a range of colors depending on the species. The colors include: bright and clear pink, dark red, brown, and black. Unless you look really closely, you will notice the pupil more than the iris (which is white in a human eye). So really, there eyes seem to be one round color.
Like all mammals, humans included, the retina is made up of rods and cones. Rod cells help us see in low light. Cone cells help us see in bright light. Hamsters have more rods, and fewer cones. This explains their near blindness in bright light, and their nocturnal practices. Who really wants to be awake when it is difficult to see?
In many ways, the nocturnal nature of hamsters explains their poor eyesight. Wild hamsters live underground, where they spend the days sleeping. They come out and forage for food at night. This is the time when their eyes work best, but they still must depend on their other senses for survival. There eyesight is simply not good enough to keep them safe.
Do hamsters see in color?
For this we need to look again at the science of the eye. The ability to see colors depends on the number of cones, as well as if those cones contain the pigments (called opsins) that respond to different wavelengths of light. The wavelength of light defines the colors we see. Most humans have red, green, and blue opsins, enabling us to see a wide spectrum of colors. Most other animals have only blue and green opsins, which limits them to the blue and green spectrum of colors.
What does that mean for our friend, the hamster? That’s difficult to say, because we can’t look through the eyes of a hamster. Some studies suggest that hamsters are monochromatic, meaning that they probably only see in shades of one color. Other studies suggest that they can, indeed, seeing blues and greens. It really comes down to the number of cones, and the way their brain processes the information. However, since about 97% of a hamsters cells are rods, rather than cones, the possibility of them seeing much color is pretty minimal.
On a surprising side note, some studies suggest that hamsters can actually see ultraviolet light. This might help them avoid predators, unless the predators have the same capacity to see them. Nobody really knows how this ability benefits these tiny critters.
What do hamsters see?
Again, since we are not hamsters, much of this is speculation. But given all that we’ve explored today, we can come to some basic conclusions, and acknowledge some known facts:
- Baby hamsters are born blind, and are very light sensitive.
- Adult hamsters can’t see very much in bright lights. If you think they are looking at you lovingly, you’re probably incorrect. It’s more likely they are aware of who you are based on the powerful sense of smell.
- Hamsters are nearsighted. Since cones help focus the eyes, their lack of cones means everything is blurry.
- They see best in low light conditions. Not total darkness, and definitely not bright light.
- They mostly see in black and white, but might also see pale shades of blue and green.
- They have binocular vision, meaning they have good depth perception (similar to humans)
- Hamsters see well enough to investigate their food and catch insects.
- The give each other visual social signs–like stay way. (Hamsters aren’t very social animals)’As they don’t see well in bright light, they slow down and become less active in response to it.
Understanding your cherished hamster’s eyesight, as well as their other senses, will help you keep them healthy and happy. And maybe you will forgive them if they keep you up at night.