Chameleons, octopuses, cuttlefish, and snowshoe hares change color naturally, but the appearance of a white Iberian lynx in the mountains of the Spanish province of Jaén is surprising, even unbelievable. The animal, a female known as Satureja, has lost her natural coloring — the brown and orange tones so characteristic of the species. She has, however, retained the black spots unique to each lynx: a kind of natural ID that lynxes keep for life and that allows researchers to distinguish one individual from another.

No one knows the reason for this striking change in coat color, which had already been observed in another lynx previously. Javier Salcedo, coordinator of the Iberian lynx reintroduction program in the Spanish region of Andalusia, suggests it could be a temporary depigmentation due to external factors — environmental or stress — rather than a genetic mutation leading to albinism or leucism.

Researchers point to the case of another female lynx — possibly related to this one — that experienced the same loss of pigmentation and eventually regained her natural tones. The Andalusian government’s Ministry of Sustainability and Environment, however, has referred the matter to the ongoing investigation.

“When an animal doesn’t normally change color, and it does so suddenly, an environmental factor cannot be ruled out,” explains Ismael Galván, a senior scientist at the Spanish National Research Council (CSIC) at the National Museum of Natural Sciences (MNCN) and a specialist in pigmentation. The problem is that, currently, researchers “don’t fully understand the external agents that could cause these changes, and it’s possible that environmental pollution could be affecting the coloration,” he says. That’s why it’s so important, he argues, to investigate the origin of these types of anomalies.

Galván cites as an example the anomalous changes being observed in the pigmentation of mantled howler monkeys (Alouatta palliata) in Costa Rica, with whom he has worked. For about 10 years, these primates have been undergoing a dramatic color change. “It’s very striking, because they go from being completely black to individuals with orange and yellow patches,” he says. At first, only a few were affected, and the transformation only affected their limbs, legs, or tails, “but there has been an increase both in the number of affected individuals and in the extent of the altered body areas, and now there are entirely orange howler monkeys.”

What’s behind this? “There’s a lack of research [to reach a conclusion], and it’s not just monkeys; these anomalies have also been detected in porcupines and toucans,” he says. Melanins are responsible for the black, brown, reddish, and yellowish tones of skin, hair, fur, and feathers. In the case of howler monkeys, they are losing the melanin responsible for black tones in favor of orange, while in the Iberian lynx that has appeared in Jaén, the process is the opposite: the orange pigments are fading, and the black ones remain.

The pigmentation changes in the monkeys may be linked to exposure to agrochemicals used on nearby plantations. “But it’s a hypothesis we haven’t yet been able to investigate in detail,” Galván explains.

The most common cause of animals being born with a different pigmentation than their natural one is a genetic mutation. Natural selection usually ensures that such animals don’t survive. One such alteration is albinism, which occurs randomly and results in a complete absence of melanin. In the case of Satureja, albinism has been ruled out, as in that case she should be completely white, without any black markings. The gorilla Snowflake was one of the most famous cases of albinism in the world. He was captured as a baby in Guinea in 1966 and lived in the Barcelona Zoo until his death in 2003 at the age of 40.

Another genetic anomaly is leucism, in which the animal produces melanin but it fails to reach certain areas of the body, which appear white or very pale. This doesn’t appear to be the case either, since Satureja doesn’t display that pattern.

Furthermore, both conditions (albinism and leucism) are present at birth, and these two lynxes, according to the coordinator of the lynx reintroduction program, were born with their normal coloration. The depigmentation appeared later.

The role of 700 genes

Lluis Montoliu, a researcher at the Spanish National Research Council and the Center for Biomedical Research in Rare Diseases at the National Center for Biotechnology, explains that “there are almost 700 genes that, in one way or another, directly or indirectly, control pigmentation in animals (and in us), out of the approximately 20,000 genes that both the lynx and we humans possess, given that we are both mammals.” Of those, only 22 are known to cause albinism when mutated, and a few others can lead to leucism.

But there are many more that “can alter pigmentation in multiple ways,” he adds. For example, some gradually switch off, as happens with silver horses, which are born with normal coloration but lose pigment over time until they turn white. “Little Uncle, the horse from [the children’s series] Pippi Longstocking, was one of these horses, and before each scene, they would paint on the black circular spots that we all remember,” he recalls.

This horse is a model of vitiligo, “possibly one of the explanations for why this lynx may have lost pigmentation on its body.” This skin condition has both genetic and environmental causes (there are at least 40 genes whose alteration predisposes individuals to vitiligo), and external factors: friction or exposure to chemicals can also trigger pigment loss by destroying or depleting melanocytes, the cells responsible for producing melanin.

But to know for sure what might have happened to this lynx, “we would first have to sequence its genome and see if it carries mutations in any of its 700 genes.” It would also be necessary to perform “a histological analysis [tissue study] of its skin” and check if it lacks pigment because its melanocytes aren’t producing it or because those cells have disappeared. “The latter would suggest that the cause of this pigment loss could be related to vitiligo,” Montoliú explains.

To obtain Satureja’s genome, it would be enough to collect a few hairs, droppings, or saliva samples. A histological analysis, however, would require taking a skin biopsy — something far more complicated, since she was born in the wild and does not have a GPS tracking device.

For now, she appears to be in good health. She has successfully raised several litters and shows no signs of difficulty hunting or feeding despite her white coat. Technicians from the Iberian lynx recovery program capture a few individuals each year to monitor the population’s overall condition, but they do not target specific animals.

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