Researchers have determined that medium-sized carnivores spend more time hunting for food than smaller and larger carnivores. This means that climate change will have a bigger impact on medium-sized predators, as changes in the environment will affect the availability of their food.
It has been long assumed that foraging time decreased as animal size increased. But now, a study from Imperial College London and the Zoological Society of London demonstrates that this is not the case.
The researchers obtained data on land predators worldwide, from small predators to large predators. For their investigation, the team used tracking methods such as radio collars and GPS. Overall, they examined 73 land-based carnivore species.
The analysis revealed that medium-sized species of predators, such as the leopard cat and the crab-eating fox, spent the largest amount of time foraging. The researchers explained that the findings of the study provide a more accurate model to forecast the vulnerability of animals to habitat loss and climate change.
“We propose a simple mathematical model that predicts how foraging time depends on body size,” said study co-author Dr Samraat Pawar. “This can help predict potential risks to predators facing environmental change.”
“Habitat changes can mean that predators have to move more to find the same amount of food, causing them greater stress,” said Pawar. “This impacts the health of the individual, and therefore the health of the population.”
Study co-author Matteo Rizzuto explained that the extent to which species are vulnerable will also depend on the kind of prey they feed on. “If they are able to adapt their diet and diversify their prey, they may fare better,” said Rizzuto.
The mathematical model developed by the researchers helped explain why medium-sized predators spend so much more time searching for food. This is because they tend to feed on animals that are small in relation to their own body size.
Study co-author Dr. Chris Carbone said, “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’.”
The study is published today in the journal Nature Ecology & Evolution.