The striking eyes of gorillas have captivated people for centuries. Their deep brown irises hold mysteries about gorilla genetics, evolution, and behavior. If you’ve ever wondered why gorillas have brown eyes or if they can have other eye colors, you’ve come to the right place.
If you’re short on time, here’s a quick answer to your question: Gorillas always have brown eyes. Their eye color is determined by genetics and is the same across gorilla species and subspecies.
The Genetics Behind Gorilla Eye Color
Melanin and Iris Pigmentation
The iris of gorilla eyes contains melanin, which is a pigment that gives color to the skin, hair, and eyes. The amount and type of melanin present determines eye color. Gorillas have two types of melanin – eumelanin which produces brown/black pigments and pheomelanin which produces red/yellow pigments.
Gorillas have high levels of eumelanin which makes their irises appear dark brown or black. The density of melanin packed in the iris affects the eye shade. More melanin results in darker eyes while less melanin leads to lighter golden or brown eyes.
Albino gorillas with genetic mutations have little to no melanin which makes their eyes pinkish-red.
The Role of Tyrosinase
Tyrosinase is a key enzyme involved in melanin production. It catalyzes reactions that convert tyrosine into melanin pigments. Gorillas have high tyrosinase activity which increases melanogenesis and leads to abundant eumelanin deposition in the iris.
Mutations in the tyrosinase gene can significantly reduce enzyme activity and melanin synthesis, resulting in blue eyes in some gorilla species like gorillas. The specific amount and type of melanin in the iris is precisely regulated by genetic factors influencing tyrosinase expression and activity.
Comparing Gorilla Eye Color to Humans and Other Primates
Iris Colors in Humans
Humans have a wide variety of iris colors, ranging from light blue and green to dark brown and black. The amount and distribution of melanin pigment in the iris determines eye color in humans. Blue and green eyes have less melanin, while brown and black eyes contain more melanin.
Interestingly, all human babies are born with blue eyes, which darken over the first few years of life as melanin levels increase.
The most common eye colors among humans are brown, blue, hazel, and green. However, some rare eye colors also exist like amber, red, violet, and gray. The rarest eye color in humans is green, occurring in only about 2% of the global population.
Geographic ancestry and genetics influence the prevalence of specific eye colors in different human populations.
Chimpanzees and Orangutans
In contrast to the variety seen in humans, our closest primate relatives like chimpanzees and orangutans have a narrow range of iris colors. Nearly all chimpanzees have brown or dark brown eyes due to high levels of melanin in their irises.
This likely provides an evolutionary advantage by protecting their eyes from intense sunlight in the tropical regions where they live.
Orangutans similarly have dark brown eyes for sun protection in their native habitats in Southeast Asia. The iconic orange hair of orangutans is a distinct feature from their eye color. Like chimps, melanin pigment gives orangutans’ irises a deep brown hue that appears nearly black in some individuals.
While rare blue-eyed individuals have been documented in both chimp and orangutan populations, the overwhelming majority have brown eyes. In comparison, the wide spectrum of light to dark eye colors in humans is unique among primates.
Do Albino Gorillas Exist?
Albinism is a rare genetic condition that affects the production of melanin, the pigment that gives skin, hair, and eyes their color. Since gorillas with albinism lack this pigment, they have white or very pale skin and hair, along with light-colored eyes.
So far, there have only been a few documented cases of albino gorillas in the wild or in captivity. In 2008, zookeepers at the Barcelona Zoo in Spain announced the birth of an albino Western lowland gorilla named Snowflake. Snowflake had white fur, pink skin, and blue eyes.
Unfortunately, Snowflake passed away just a few months after birth due to health complications related to his albinism.
Another report from 2019 described the sighting of a young albino gorilla named Mugaruka living in Volcanoes National Park in Rwanda. Conservationists captured photos and videos showing a gorilla with entirely white fur playing with others in his group.
While albinism made Mugaruka stand out, observers say he seems healthy and is accepted by the other gorillas.
Albino gorillas face greater odds for survival both in the wild and in captivity. Their unusual appearance, poor eyesight, and increased sensitivity to the sun can make social integration difficult. Without melanin to shield from UV radiation, they require extra care to prevent skin cancer and other health issues.
Still, the occasional albino gorilla provides valuable proof that this rare genetic trait can occur even among great apes. Their distinctive looks offer researchers an opportunity to study how albinism affects gorilla development and socialization.
While albino gorillas are exceptionally rare, their existence demonstrates the genetic diversity found within endangered gorilla populations. Conservationists hope Mugaruka, Snowflake, and other albino gorillas can help raise awareness about protecting these magnificent but vulnerable great apes.
The Significance of Gorilla Eye Color
Camouflage and Avoiding Predators
Gorillas have brown or dark colored eyes which help them blend into their forest surroundings and avoid predators. The dark pigmentation in their irises acts as camouflage against the lush green rainforests of Africa where they live.
When a gorilla is staring directly at you, their dark brown eyes can be difficult to distinguish from the shadows of the forest.
Their eye coloration is an evolutionary adaptation to evade predators like leopards, which hunt gorillas. Having darker eyes breaks up the shape of the gorilla’s face, making them harder to spot. It’s an ingenious and amazingnatural defense mechanism that has ensured gorillas’ survival for thousands of years in the jungles of Africa.
Social Signaling
In addition to camouflage, gorillas’ eye colors also serve an important social function. Their varied shades of brown help communicate emotions and reinforce social bonds within their troops.
For example, when a male silverback gorilla stares down a rival with his piercing dark eyes, it signals aggression and acts as a warning. The contrast between the silver hairs on his back and dark brown eyes make him appear even more formidable.
In play, a young gorilla may soften its gaze to indicate friendliness. Light brown or amber colored eyes can demonstrate curiosity, interest, or excitement during social interactions. The subtle variations in gorilla eye color and expression are an essential part of their nonverbal communication.
Conclusion
The characteristic brown eyes of gorillas are a product of evolution and play an important role in their survival and social interactions. While limited genetic variation means they can’t have blue or green eyes like some humans, the intense coloration serves them well in the tropical forests of Africa.
The next time you gaze into the eyes of a gorilla, appreciate the story they tell about these magnificent primates.
