Monkeys are ridiculously intelligent creatures. They’re quick, agile, curious and astounding primates. Unfortunately, we the human race continue to let them down. Researchers began noticing a shift in the appearance of a particular type of monkey in Costa Rica. And this makeover could have dire consequences.

What’s in a pigment?

The mantled howler monkey in Costa Rica is a species of monkey named for its long facial hairs that frame the face. Many environmentalists and scientists recently noticed a lighter shade to the monkeys’ normally dark brown and black coat.

Mongabay/Arturo de Frias Marques/Wikimedia Commons

To further investigate, researchers studied the pigment of this lighter hair. Their typical melanin is called eumelanin, which creates the darker colors. However, the blonde patches contained an additional substance- sulfur.

Human intervention

So where could these primates be getting a daily dose of sulfur? Scientists immediately knew this answer. Costa Rican farmers usually use a type of pesticide on their trees and plants that contain the chemical. The monkeys then treat themselves to fruits of these trees, leading to an influx of sulfur in their bodies.

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The heartbreaking truth is that our additions to the environment drastically affect those trying to live among us. It may seem like a trivial, harmless shift in appearance, but there could be serious outcomes for the primates. What we view as “cute” highlights could mean big trouble for the long-fingered fellow.

The future of the howler

The deep, dark color of the mantle howler monkey’s coat isn’t just aesthetically beautiful. It serves a distinct purpose. The browns and blacks and grays help to conceal the monkey amongst the forest greenery, keeping them hidden from predators.

Retired in Costa Rica/Charlie Doggett

With continued sulfur intake, the monkeys may completely change color. In fact, some all over blonde monkeys have already been spotted, completely visible to the naked human eye. How will this affect this unique species? Only time will tell.