Horse Sense and Sensibility

Product Information

Colonel Brandon is due to soon visit soon, and Elinor looks forward to his arrival. Just when she is expecting him, though, someone else arrives: Edward. He tells her that he hasn’t married Lucy; his brother Robert has! Elinor cries tears of joy. Edward explains that he had foolishly become engaged to Lucy when he was too young and idle. They didn’t really love each other, and she had left him for his wealthier brother. He now proposes to Elinor, who accepts, to the delight of her sisters and mother. Such a highly developed olfactory apparatus indicates that information from odors is important to horses, but despite being a central sensory modality, research on olfaction is relatively scarce for this species. Only a handful of studies have examined the role of olfaction in horses, and these have mainly focused on reproduction and social recognition. Marinier et al. ( 82) found that stallions did not differ in their response to the odor of urine and vaginal secretions of a mare in estrus as compared to when that same mare was not in heat. Later, Briant et al. ( 83) and Jezierski et al. ( 84) supported those findings by showing that stallions could not differentiate feces of mares in estrus from those in diestrus. We know that odorant differences exist between these equine feces types, as male rats are able to distinguish between them by smell alone ( 85). From an evolutionary perspective, the ability to use odors for estrus detection may have been lost (or never existed) in horses, as stallions either lead a predominantly female harem or belong to an all-male group of younger horses. When surrounded by mares, odors may be unnecessary for estrus detection as only mares in estrus will allow a stallion to mount her. Stallions thus rely on the mare's behavioral responses when determining whether or not she is ready for mating. Have you ever seen a horse quietly follow a calm buddy into the trailer but then become anxious when loaded alone? Or maybe you’ve been on a trail ride when one horse suddenly startles and spins, causing the others to startle as well. These are examples of social buffering and emotional contagion—when one individual is affected by or shares the emotions of another¹ ,²—and provide evidence that horses possess the capacity for empathy. What is empathy?

Yamamoto, S. and Takimoto, A. (2012). Empathy and fairness: Psychological mechanisms for eliciting and maintaining prosociality and cooperation in primates. Social Justice Research (25), 233-255.

Smell

Sound waves are formed by vibrations. If your horse is in range of sound waves (before those vibrations run out of energy and stop), they’ll hear that sound. The structure of your horse’s ear helps them capture more sound… External ear

Moreover, some individuals are fundamentally more empathetic than others, and in humans scientists have linked these differences to brain activity. When someone who doesn’t feel empathy hears about or sees another person in pain, the brain areas associated with empathy do not light up, and in extreme cases of psychopathy, the brain’s pleasure centers might even become active. Animals, like humans, have five basic senses: vision, audition (hearing), olfaction (smell), gustation (taste), and touch. The senses are an important part of what makes horses behaviorally distinct. They are the tools that a horse uses to interact with its environment. As such, the senses can be considered behavior starters. We do not completely understand the horse senses, but what we have learned has greatly added to our knowledge of horses. A review of this information can be helpful in understanding horses.

Chapter 50

Horses show visible reactions to sounds, with one or both ears typically moving toward the direction of the sound source. The hearing ability of horses was first studied in the 1980's by Heffner and Heffner ( 46– 48) and surprisingly little research has been done on horse hearing since. They mapped the range of frequencies horses can detect and demonstrated that while larger animals tend to be adept at hearing lower frequencies, horses are an exception. The lowest frequency detectable by horses is 50 Hz, which is higher than the lowest human detection threshold of 20 Hz. Conversely, equine hearing exceeds the highest frequencies that can be heard by humans (33 kHz compared to 20 kHz for humans), indicating that there will be situations where a horse can detect sounds that humans are unable to hear, and vice versa. Furthermore, the funnel-shape of the equine ear provides an acoustic pressure gain of 10 to 20 dB ( 49) improving the acuity of equine hearing. From the viewpoint of horse-human interactions, it is important to consider that the higher frequency hearing abilities of horses compared to humans may explain some of the unwelcome and otherwise inexplicable behaviors that are regarded as problem behaviors. New tastes follow the same sensory pathway as your horse’s sense of smell. So, horses can instantly get important information about any new tastes and store it for the future (like filing away the memory of, say, poisonous plants or wormer, and avoiding those tastes – as best they can – from that moment on!). Sight It’s believed horses have ‘dichromatic vision’, meaning they can see two colours best – usually shades of yellow and blue. However, recent research by the University of Exeter, which helped improve safety in jump racing, suggests horses are unable to differentiate between shades of red and orange.