Amazing Goat Eyes and Remarkable Senses!
Why Do Goats Have Rectangular Pupils? How Can We See from Their Point of View?
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When you gaze lovingly in your goats’ eyes, do you wonder, “Why are goat eyes rectangular?” The answer lies in their specially adapted eyesight. But that is not the whole story: they also rely on great hearing and a discriminating sense of smell. Their senses differ from ours considerably, both in range and sensitivity.
This can lead to misunderstandings, as they perceive life differently than we do. In every situation, it is always helpful to consider this question: how do goats see it? Understanding their perspective can help us to handle them sensitively when caring for goats. When housing goats, it can help us experience the facility from the occupants’ point of view.
Goat eyes and senses were honed by many millions of years of evolution before we domesticated them, and are still tuned to protect them against predation and deal with the challenges of their natural environment: finding food and water, climbing, sheltering, competing, finding mates, and protecting young in dry, mountainous landscapes.
Why do goat eyes have rectangular pupils?
First, let us look at goats’ amazing vision. Goat eyes are placed on each side of the head and pupils are horizontally elongated. As goats tilt their heads, the pupils rotate to remain horizontal. But why are goat eyes like that? This configuration allows them to see clearly and sharply almost all around them—ahead and to the side—for 320–340 degrees. There is just a narrow blind spot behind the head.
This panoramic view enables them to watch out for predators while they are foraging—an essential skill at range and in their wild environment. To aid rapid escape, goats have 63 degrees of binocular vision, giving depth perception for jumping and climbing over difficult terrain.
Slit pupils allow a greater range of light control: constricting tightly against the dazzle of the sky while retaining light capture from the landscape. Coupled with their sensitivity to movement, this allows goats to easily spot land predators. The pupils open wide in low light, and there are many light sensors (called rods) in the retina and a shiny retina lining, the tapetum lucidum, to enhance night vision. Goats are thus able to stay vigilant while foraging early in the morning and late in the evening, avoiding the heat of the day.
Goat eyes focus well on distant or middle-distant objects, but sometimes goats need a little help distinguishing motionless individuals from afar, especially people, who frequently change the color and shape of clothing. Gentle movement and a call can help your goats to recognize you at a distance.
How do goat eyes see color?
Goats eyes pick up light ranging from the violet/blue through green to yellow/orange part of the spectrum due to two types of color receptors in their retina, called cones. One type is most sensitive to blue light, while the other to green. Humans have an additional cone type that is sensitive to red light, so that we can distinguish red as a separate color from green and yellow. Most color-blind humans and many mammals, including goats, cannot see the difference between red and green which may appear similar to yellow.
What other senses do goats have?
Close up, where focus is limited, their excellent senses of smell and touch take over. Nearby items are first sniffed and then felt using their sensitive lip whiskers, which guide their agile lips to grasp tasty morsels. The lips are indeed their main grasping tool and everything is investigated thoroughly, leading many to believe that goats are eating the items they examine.
Normally, this is just curiosity and non-edible objects are ejected after a nibble. Grooves on the inside of lips (called rugae) are very pronounced in the goat and are used to grasp and manipulate rough vegetation. It is amazing how such dexterous and sensitive mouths can navigate sharp thorns and withstand stings and prickles!
Lips and muzzles are also used to manipulate objects, doors, and the locks to gates and pens, much to the dismay of goat keepers (but to the delight of documentary makers filming Buttercups goats on TV). Lips are what goats use for hands!
As social mammals, goats are very touchy-feely, and enjoy gentle stroking and scratching from other goats or humans even into adulthood.
Do goats have a good sense of smell?
Goats’ great sense of smell also plays an important role in feeding, avoiding predators, and social activities. The damp skin on their noses and inside their nostrils has many more sensors than humans have. They identify and choose food from its smell. Moreover, they navigate a sensory world that is hard for us to imagine, guided by messages left behind by other animals in odor form. Mothers bond with their young initially by learning their unique scent. Visual and vocal recognition follow soon after.
Pheromones in goats’ saliva, urine, and scent glands are unique to each individual and give information about a goat’s identity, sex, health, sexual receptivity, and possibly emotion. Scent glands are located behind the horns, under the tail, and between the front toes.
Goats sniff one another at the mouth on meeting, gaining prior information before challenging for a rank in the pecking order. They also like to sniff other animals and humans on introduction. I’ve found that it helps shy goats to accept new humans if we crouch down and let them sniff us, allowing the goats to approach in their own time.
Goats rarely need a sniff update unless one of the herd has been away for a while or if something about her has changed. I’ve seen companions sniff mouths and horns during combat and play, possibly to check up on how they are. My goats also sniffed me when I was injured. Females sniff each other when one of them comes into heat, and they pay a lot of attention to their companions’ estrus progress.
Pheromones, hormones, and other animal signature mixes are non-volatile, water-soluble chemicals, so they need absorbing into the damp tissues of the nose and mouth before they can be analyzed. They are then drawn down into an organ between the two, called the vomeronasal organ. This is achieved by pulling a comical expression called flehmen. The smelly truth about goat reproduction includes the sampling of urine. Bucks examine the urine of females using flehmen to check if they are ready for mating. Females also use flehmen to examine animal scents.
Goat hearing range and the meaning of bleats.
Goats can hear a wider range and much higher pitches than humans (goats: 70 Hz to 40 KHz; humans: 31 Hz to 17 KHz). They often become alert to sounds that we cannot hear. They may become disturbed or distressed by sounds such as the high frequency squeaks of electric machinery and metal devices, many of which are imperceptible to us. Sudden, loud, or high-pitched sound, such as children’s screams and people’s laughter, can trigger an alarm response. This makes sense, as goats emit loud, high-pitched, shaky bleats when they are in trouble. Kids’ bleats are high-pitched to attract the urgent attention of their mother. Aggressive bleats are harsh and deep.
Locating sound is not as accurate in goats as it is in humans, so they swivel their ears to pinpoint the direction of each noise. A wary goat, listening out for danger, can often be seen with ears pointing in different directions.
Sound is also used in communication between herd members. There are gentle bleats used simply to maintain contact: quiet, steady, low-pitched, and often delivered with the mouth closed. Dams mutter to their kids in this way. You can emulate these gentle sounds to keep your goats calm during handling.
Understanding goat eyes and senses makes for easier handling.
Sensory information is combined to give goats several ways of detecting danger, food, and friends in varying conditions, such as when vision is obscured. Memory is also stored and triggered by the senses. Goats may associate a place, shape, color, or item of clothing with an unpleasant event, and remember it for some time. Equally, goats readily associate sights, sounds, and smells with good experiences, which means that we employ goat training to make management procedures run smoother.
Goat eyes give them amazing vision and their sharp senses protect them out at range. Understanding goat senses helps us to manage our herd more easily.
Goats may not understand many of the things that we do, and will interpret some of our actions in ways that we did not intend. When we catch them for treatment, we trigger an instinctive fear of having their movement restricted. When we stray from our normal routine, we introduce a degree of insecurity and fear of the unknown.
When handling goats, we employ a calm demeanor, use slow gentle movements, and converse in gentle tones to keep the animals calm and avoid triggering their sensitive predator alert system. We gently introduce them to new areas and equipment. We do not rush them, but let them sniff, listen, and explore. By using our knowledge of goat perception and how goats think and feel, we can understand their reactions to their environment and make handling easier and more efficient.
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Color diagram © 2014 CC BY Fedigan et al. 2014. The Heterozygote Superiority Hypothesis for Polymorphic Color Vision Is Not Supported by Long-Term Fitness Data from Wild Neotropical Monkeys. PLoS ONE 9(1): e84872.
Originally published in the September/October 2019 issue of Goat Journal and regularly vetted for accuracy.
