Naked Science Forum

Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: thedoc on 06/08/2015 20:50:01

Title: Why do some predators have yellow eyes?
Post by: thedoc on 06/08/2015 20:50:01

Rod Kirkby  asked the Naked Scientists:
   
When I was in Canada, I saw a rather fine painting of wolves, noticing particularly the strikingly yellow pupils.
 
 When I thought about it, I realised most of the big cat paintings I have done featured yellow irises, and, I then realised that most of the birds of prey I had painted also had yellow irises (orange in owls).
 
 A physicist by training and an aerospace engineer by career, I am intrigued.
 
 Clearly, predators need especially good eyesight, but I could not think of any reason why yellow irises could help visual acuity.
 
 Any ideas?
 
 Kind Regards
 Rod
What do you think?

Title: Re: Why do some predators have yellow eyes?
Post by: RD on 07/08/2015 00:51:46

If the yellow iris is less opaque than a brown one then it could benefit night-vision : analogous to "fogging (https://en.wikipedia.org/wiki/Fogging_%28photography%29#Light_fogging)" photographic-film to increase it's sensitivity.

Title: Re: Why do some predators have yellow eyes?
Post by: Don_1 on 11/08/2015 11:59:17

A damn fine question Rod.

You are not quite right about the iris colour of owls though. This just might go some way to helping understand this eye colour business.

According to Raptor Rescue (a bird-of-prey rehabilitation charity), there is some correlation between the eye colour and time of active hunting in owls.

Owls with orange eyes tend to hunt around dawn and dusk (crepuscular). Those with brown and black eyes hunt during the night (nocturnal) and those with yellow eyes are daytime hunters (diurnal).