What makes animals see in the dark

Maybe in the summer you could walk your dog after dinner and come home before the sun set, but not anymore. The nights will continue to get longer until late December.

But human eyesight functions much better during the daytime. Keep reading to find out why that is and why some animals see much better than you do after dark. The human eye lets light in through a hole called the pupil. A lens inside the eye focuses the image, and the retina detects that image—you might picture the retina as the wall a projector puts the image on.

The retina contains two structures called rods and cones that detect light and send the image to the brain. Rods are great at capturing very dim light and movement. However, they do not detect colors. We can see colors so vividly because of cones, which can only function when there is plenty of light.

We have four times the number of rods than we have cones. This ratio means that we see pretty well during the day, and though we have more rods than cones overall, we have more cones than many animals. In diurnal animals, the chromosomes in the nucleus are densest around the edges, which means that any absorbed light is scattered around the edges.

In nocturnal animals, the densest material is in the center of the nucleus, effectively focusing all of the available light in one area. One can only guess at what nocturnal animals see. Most nocturnal animals also have a highly developed sense of hearing, touch e. Many animals designed for night vision have only rod cells in their retinas, and lack cone cells entirely.

What disadvantages would such an arrangement have for seeing in daylight? The creature was standing in the dark beneath a towering pine. Wonderful piece. Thank you! To ensure a respectful dialogue, please refrain from posting content that is unlawful, harassing, discriminatory, libelous, obscene, or inflammatory.

Northern Woodlands assumes no responsibility or liability arising from forum postings and reserves the right to edit all postings. Thanks for joining the discussion. Why do you think this happens? The pupil of our eye widens in the dark to get in more light. This is true for many animals around us; the most common ones we know are cats and owls. Animals like cats, wolves, foxes, mice, bats and owls are active almost exclusively in the dark.

They hunt at night and stay safe from predators because of their ability to see in the dark. In fact, for these animals which are also called nocturnal animals, their vision is better at night as compared to the day. What is different in the eyes of these nocturnal animals that we lack in ours?

As mentioned earlier, not only do these animals have bigger eyes than humans, their pupils also tend to open wider than ours which help in letting in more light.

For example, the eyes of an owl are so big that they occupy more than half the volume of its skull. It can see so well in the dark that it can probably sense a mouse anywhere on a football ground in the light of a single candle.

Many such animals have a layer behind their retinas, which is called a tapetum. The tapetum reflects the light coming through the retina once again onto the retina, just like a mirror.