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Discussion on Research Summary: Horses and Color Vision
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Moderator:
DrO
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Posted on Tuesday, Apr 15, 2008 - 7:03 am:
Here we present the latest piece of evidence for that eternal question: do horses see color? Findings here are similar to earlier results suggesting that horse do see some colors, particularly blue and yellow, but not all the colors humans see, at least not as well as humans do. Red and green deficiencies seem to exist but they are not absolute.
DrO
Behav Processes. 2008 Feb 13;
An investigation of colour discrimination with horses (Equus caballus).
Blackmore TL, Foster TM, Sumpter CE, Temple W.
University of Waikato, Hamilton, New Zealand.
The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green.
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Member:
erika
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Posted on Thursday, Apr 17, 2008 - 9:24 am:
Interesting. If I were a horse, I think I would really like to be able to spot green! Since that is what they seek out, I'm surprised they aren't wired for that.
But I guess that most growing green things have a blue or yellow tinge to them too.
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Member:
maggienm
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Posted on Friday, Apr 18, 2008 - 11:16 am:
Erika, good point.
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Moderator:
DrO
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Posted on Saturday, Apr 19, 2008 - 10:14 am:
Keep tuned! This report and other important recent findings has sparked an article on a horses' vision overall that is shaping up nicely and should be available next week.
DrO
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Member:
alden
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Posted on Wednesday, Apr 23, 2008 - 7:11 pm:
I often treat my horses to mountain grass for 30-40 minutes when riding in the high country. My observations of their grazing has been they use their sense of smell to find, sort and reject grass. Eyes and ears are constantly scanning the surroundings, I presume for danger as they are prey animals.
It would be interesting to observe a blind horse to see if they have trouble finding grass. I'd be very surprised it they did 
Good day,
Alden
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Member:
ekaufman
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Posted on Thursday, Apr 24, 2008 - 10:02 am:
Hi Alden,
I have a blind horse who could find grass under a tarped sand pile, in the rain, next to a skunk!
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