Because the leopard cat hunts for smaller, more elusive prey, it spends more time hunting than its peers, both larger and smaller. Photo by Imperial College London
Dec. 4 (UPI) -- Because medium-sized carnivores spend the most time hunting for food, they're most likely to be negatively impacted by environmental changes, new research shows.
Until now, scientists thought foraging time decreased with body size: the bigger the animal, the less time the animal spends foraging. But new research by scientists at Imperial College London suggests medium-sized species -- including the Malay civet, Iriomote cat, Leopard cat and Crab-eating fox -- spend more time looking for food than their peers, both bigger and smaller.
As such, medium-sized carnivores are most at risk from environmental changes that affect the distribution and abundance of their prey.
The new research -- published this week in the journal Nature Ecology & Evolution -- could help conservationists identify species that warrant extra protections.
"We propose a simple mathematical model that predicts how foraging time depends on body size," ICL researcher Samraat Pawar said in a news release. "This can help predict potential risks to predators facing environmental change."
Scientists confirmed the accuracy of their math model using GPS and radio collar tracking data from surveys involving 73 land-based carnivore species.
"Habitat changes can mean that predators have to move more to find the same amount of food, causing them greater stress," Pawar said. "This impacts the health of the individual, and therefore the health of the population."
In order to put the new research to good use, scientists also need to have an accurate understanding of the diets of medium-sized carnivores. Medium-sized species with highly-specific diets would likely be most at risk from environmental shifts.
"If they are able to adapt their diet and diversify their prey, they may fare better," master's student Matteo Rizzuto said.
Researchers suggest medium-size carnivores have to spend more time foraging because they tend to feed on prey that are significantly smaller than themselves. Large predators, like lions and tigers, tend to feed on much larger species.
"Prey that are much smaller than a predator are hard to find and catch, and therefore do not easily satisfy the predator's energy needs and provide insufficient 'bang for the buck,'" said Chris Carbone, a scientist at the Zoological Society of London.
