New Delhi: Human activity is making the natural world increasingly noisy, with potentially devastating consequences for wildlife. A new study published on 5 November in Science finds that noise from traffic, shipping, industrial operations and other sources can disrupt animal behaviour, damage physiological functions and interfere with interactions between predators and their prey.
In the study titled “Echoes of the Anthropocene: Noise pollution as a global threat”, researchers from the UK analysed more than 200 experimental studies covering 177 aquatic and terrestrial species across six continents.
They found that noise altered biological traits in approximately 80 per cent of the species examined, affecting everything from reproduction and immune function to survival. Across the studies, mortality increased by as much as 138 per cent, while overall fitness declined by 27 per cent through direct deaths and other harmful effects.
How noise disrupts wildlife
Animals respond to unfamiliar or excessive noise in several ways. Prey species may increase their defensive behaviour, spending more time hiding or avoiding potential predators. These changes can make hunting more difficult for predators, which may have to expend considerably more energy to find food.
The researchers found that predators increased their hunting effort by more than 150%, even as their hunting success fell by approximately 25%. In effect, they were working harder but catching less prey. Marine predators such as killer whales can also struggle to detect prey when underwater noise interferes with the sounds they use to navigate and hunt.
Noise pollution can also affect the relationship between parents and their offspring. Some bird species respond to noisier surroundings by increasing parental care, which can improve offspring weight. Others reduce their care, potentially lowering the chances of their young surviving.
The effects extend beyond behaviour. The researchers documented increased stress hormones, cellular damage and impaired immune responses in several species. Noise also affected reflexes, cognitive functions, specialised tissues and processes involved in mate selection.
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An increasingly noisy ocean
Marine ecosystems are particularly vulnerable because sound travels farther and faster through water than through air. Many marine organisms, from small invertebrates to whales, depend on sound to navigate, locate food and communicate via systems like echolocation.
A 2021 study in Science highlighted how shipping, underwater construction and resource exploration have increased human-generated ocean noise, disrupting the acoustic environments on which marine life depends.
However, noise does not disadvantage every species equally. The new research also identified cases in which predators benefit from changes in prey behaviour. For example, enclosed shelters can amplify sound, prompting prey animals to leave hiding places and enter more exposed areas where predators can catch them more easily.
Protecting natural soundscapes
The researchers describe noise as a widespread environmental stressor capable of producing immediate behavioural changes with long-term consequences for populations and ecosystems. They argue that conservation efforts must address sound pollution alongside more familiar threats such as habitat destruction and chemical contamination.
Their recommendations include establishing low-noise zones and acoustic refuges where wildlife can live and communicate with less disturbance. Protecting physical habitats alone, they argue, will not be sufficient if the sound environments within them continue to deteriorate.
(Edited by Janaki Pande)