Monkeys use more scent markings to combat human noise pollution

A recent research study has shed light on the intriguing ways in which the critically endangered pied tamarin monkeys adapt their communication techniques, in response to human-induced noise pollution, by increasing their scent markings.

Communication amidst the urban din

Native to a tiny geographic span in central Brazil, a majority of which now finds itself encapsulated within the urban sprawl of Manaus, the pied tamarins (Saguinus bicolor) primarily employ a combination of vocal calls and scent markings to convey messages.

But as cities grow and their natural habitats are continuously fragmented, how these primates communicate is dramatically changing.

The latest research, jointly spearheaded by experts from Universidade Federal do Amazonas and Anglia Ruskin University (ARU), examined nine distinct groups of wild pied tamarins. With the help of radio tracking, the research team shadowed each group for a span of 10 days.

Throughout these habitats, the main sources of human-made noise emanated from road traffic. However, noises from aircraft, visitors to parks, and even military operations also contributed to the cacophony.

The vital role of scent markings

Effective intergroup communication is crucial for not just the health but the very survival of a species. Pied tamarins resort to various scent markings, each serving different purposes, such as conveying territorial or reproductive information.

The study’s compelling findings revealed a direct correlation between the escalation in noise decibel levels and the frequency of scent markings. This indicates that as their vocal communication gets muffled amidst the urban noise, these primates are relying more heavily on scent markings.

Tainara Sobroza, the lead author from Universidade Federal do Amazonas, noted, “Pied tamarins produce long calls which are pivotal for numerous reasons including intergroup communication, territory demarcation, and group cohesion. With urban landscapes steadily encroaching their habitats, our data implies that these creatures’ communication techniques are evolving in the face of urban noise.”

Evolutionary adaptations and conservation

Adding to this, Dr. Jacob Dunn, Associate Professor in Evolutionary Biology at ARU, pointed out that human activities have massively altered the acoustic landscapes that many species were originally adapted to. He emphasized, “The rise in scent marking is probably a flexible adaptation to this drastic change. It’s captivating to note that pied tamarins are adjusting their behavior in the face of city noise.”

While scent markings offer the advantage of transmitting information over a prolonged period, they don’t match the reach of vocal calls. As these creatures find their habitats becoming more splintered, this might spell trouble for an already critically endangered species.

This fascinating research, which throws light on the behavioral shifts of animals in urban environments, was generously funded by esteemed institutions like the National Geographic Society, the Rufford Foundation, Primate Action Fund, and the International Primatology Society.

The findings have been unveiled in the journal Ethology Ecology & Evolution.

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