We recognize familiar things in many ways. The sense we use most often is our vision, but we can also recall a familiar sound, scent, and even touch. Animals use their senses in different ways. Dogs, for instance, smell you rather than see you. For cats, smell is also the primary way they identify people. But we don't know that much about how -- or even if -- horses recognize people.
According to a new study, not only do horses recognize familiar human faces, but they also remember them for at least a few months. Ethologist (someone who studies animal behavior) Léa Lansade of the French National Research Institute for Agriculture, Food and Environment wanted to see how good horses are at recognizing humans from photographs. In order to do this, she and her colleagues first had to teach horses to choose between two side-by-side images on a computer screen. The horses would touch their noses on one of the computer screens to make a choice.
The photos included people the horses had never seen before, as well as photos of their current keeper along with other humans the horses didn't know. It didn't always work, but horses identified their keeper in 75% of cases -- much better than chance. Even more intriguing, horses also picked photos of their previous keeper, which they hadn't seen in six months, also with 75% accuracy. This suggests that the horses have a pretty good memory and were equally likely to recognize their current and previous keeper.
This 75% rate is more impressive than it seems -- it's better than what dogs can do. The findings also suggest that horses intuitively understand that photos are 2D representations of people.
For animals, recognizing friends and familiar faces is even more important than in humans, because it tells them whether they need to be on guard (an unfamiliar face may indicate danger) or whether they can relax. Horses are social creatures -- they use vocalizations and body language to communicate to members of their herd -- so it makes sense that they can distinguish between other horses, but the fact that they can distinguish between people from photographs hadn't been proven.
Horses have been domesticated more than 5,000 years ago, so it makes sense that they've become somewhat attuned to humans. Previous studies have found that horses can read and recognize human emotions and moods and remember them, so this study also makes sense. However, it's interesting that the horses only seem to recognize their keepers in 75% of the cases -- far too high to be mere chance, but also quite a bit off from 100%. This remains a dilemma for future research.
The study has been published in Scientific Reports.