I've noticed that the cats I've had over the years don't seem to show any interest in the ambient light in a room.

Say a room is quite dark. I turn on the light switch and it's now bright as day. I notice that the cat's eyes might visibly adjust, but she'll be totally calm. Same for the opposite direction.

This has always puzzled me. Wouldn't you think animals would be more sensitive to instant transitions between day and night? Why doesn't it seem to register as an interesting event?

Do other animals care more? (I know one covers a birdcage at night, for example.)

  • I have a cat that squints its eyes when I turn on the lights for the first time in the morning. I get the impression the cat is a little irritated by the light, similar to a human-like response "Why is it so bright - I just want to sleep more!" I have never really observed this in other cats.
    – Beo
    Mar 12, 2017 at 9:54

1 Answer 1


Because cats (dogs and many other animals) eyes have very sensitive Tapetum lucidum, your cat can see you and what's going on in the room she's occupying, before the light comes on, so there is little or no reaction.

Tapetum lucidum

While it may seem counter-intuitive that she's not startled, or more sensitive to the change in lighting, it's normal for animals with superior night vision. If there were NO VISIBLE LIGHT in the room and you switched it on remotely, she almost certainly would get startled or more light-sensitive because she was unable to see in complete darkness.

Covering a bird cage has less to do with light and is more about warmth and diminishing distractions in the room which can disturb their sleep. Think blinders for horses.

  • Very interesting! Thanks. So in other words, it's because she can essentially already see what she needs to... Mar 12, 2017 at 2:32
  • @LukeSawczak Precisely.
    – M.Mat
    Mar 12, 2017 at 2:44

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