1.02.2008

Rods and cones

We stumbled upon the topic of colorblindness in animals over the New Year's dinner. (Oh, how I truly enjoy the conversations I have with my in-laws! You never know where the conversation is going to go.) Everyone in the gathering thought that animals were colorblind, and only saw the world in black and white. So, the news that my father-in-law had to share that dogs and cats have cones in their eyes that are sensitive to green and blue was news to everyone, and a chorus of "I-always-thought-that"s quickly broke out. Except for me. I have to admit, it never even occurred to me to wonder whether animals can see in color, and I certainly don't have any recollections of this topic coming up before. So, the whole topic of conversation was definitely news to me.

In a related note, it is well-known that I have one of the most adorable and lovable cats on the planet. Sadly, she rarely photographs well. She doesn't have a red-eye problem. No. She has the creepy-glowing-yellow-eye (which most photo editors do not fix) issue.

We human-folk may have three types of cones in our eyes that allow us to register blue, green, and red light, but dogs and cats and many other predatory animals have additional cells behind their retinas called tapetum lucidum. These cells act like a mirror behind the retina, and work to let cats and dogs pick up extra light at night.

So. Until photoshop comes up with tapetum-eye remover, I'm going to have to work on not using flash if I want to have a decent picture of my cat.

1 comment:

Kristin said...

I remember conducting a color experiment on my (sweet, agreeable, always willing to go along with the silly kid) dog. Using what food coloring Mom had available, I dyed two glasses of water blue and one green. I let her look at one blue glass, then led her over to the other blue and the green, set up together. She picked the blue, and I had conclusive results by dinner.

Great post—my household now has two cats, and we have again been wondering what colors they see.