Artificial light is reshaping caracal behavior

Artificial light is one of the most ingrained features of modern life. For humans, light after dark offers convenience and a sense of safety. For wildlife, it’s a growing environmental disturbance.

“When humans introduce artificial light at night, they are fundamentally altering an aspect of the environment that many species depend on for processes like foraging, navigation, and risk-avoidance,” says Christopher Hickling, a Ph.D. student in natural resources science at the University of Rhode Island. “Species also depend on light to maintain their natural rhythms and cycles.”

A new study led by Hickling shows how light impacts the behavior of caracals, a medium-sized wild cat living on South Africa’s Cape Peninsula that is similar in size and ecological role to New England’s bobcats. As they navigate increasingly urban landscapes, artificial light limits where and how caracals can move and hunt.

Why caracals?

“To my knowledge, this is the first study of its kind investigating the impacts of artificial light at night (ALAN) on the behavior of a medium-sized carnivore,” Hickling says.

Caracals are most active in low-light conditions such as dawn and dusk. “They are ambush predators,” Hickling says, “meaning they rely on cover to stalk and kill their prey.” Exposure to artificial light can disrupt that balance: Too much light reduces cover for stalking prey, while very low light may constrain prey detection, creating a narrow window of optimal hunting conditions.

Caracals also occupy a notable ecological role in a geographically isolated region. The Cape Peninsula encompasses urbanized areas—including the second-most populous city in South Africa—and borders wildlands. “Dominant species, like leopards and lions, do not inhabit this area, and caracals assume the role of apex predator,” Hickling says.

Avoiding the glow

For caracals, light shapes when, where, and how they hunt. “They rely on optimal lighting conditions to successfully hunt and survive,” Hickling says. “Introducing light at unnatural times alters the environment they depend on in a fundamental way.”

Using GPS collars and behavioral data, the researchers examined how caracals move and hunt across landscapes with varying levels of artificial light. The study considered both direct light sources, such as streetlights, and indirect sources like skyglow—diffuse illumination that spreads beyond city limits. “Many studies on light pollution only examine direct artificial light, but diffuse skyglow may also impact wildlife,” Hickling says.

Direct artificial light emerged as the strongest predictor of caracal movement, with animals consistently selecting darker areas and avoiding streetlights and highly illuminated spaces, even near preferred urban edges.

Researchers examined two survival-related behaviors: movement and foraging. While caracals continued to use urban-adjacent habitats, they avoided hunting in highly illuminated areas, revealing a trade-off between avoiding light and accessing urban prey such as rodents or birds.

Younger caracals were more tolerant of illuminated spaces than adults, highlighting age-related differences in risk-taking and adaptation. The effects of ALAN were consistent across sexes and remained strong even after accounting for vegetation cover, indicating that light itself is a primary constraint on movement and hunting.

Managing light

While individual homeowners can reduce outdoor lighting, Hickling notes that public lighting and policy may offer the greatest opportunity for change.

“Public lighting is under municipal control,” Hickling says, “so we can use research like this to influence governments to reassess the utility of artificial lighting in areas important to wildlife.”

Potential solutions include lighting curfews in ecologically important areas and re-evaluating the spectral emissions of light sources to reduce ecological impacts. Even modest changes—such as reassessing lighting near city edges—could yield significant benefits. “Public lighting is important for human safety,” Hickling says. “We need to balance reducing impacts on wildlife with social and economic needs.”

Learn more about the Urban Caracal Project at www.urbancaracal.org.

This story was written by Anna Gray in the College of the Environment and Life Sciences.