Tigers and polar bears are highly vulnerable to environmental change

Large predators are much more vulnerable than smaller species to environmental changes according to a new study.

Large predators are much more vulnerable than smaller species to environmental changes, such as over-hunting and habitat change, because they have to work so hard to find their next meal, according to a new study.

Scientists matched studies of predator populations to the abundance of their prey and found that the largest species, such as lions, tigers or polar bears, had much greater declines in population due to diminishing food supplies than smaller species, such as weasels or badgers.

The review of studies of eleven species of carnivores by researchers from Durham University and the Zoological Society of London published in the Royal Society journal Biology Letters. It suggests that the vulnerability of larger species may be linked with the high energetic costs of being "big".

The robustness and large size of these species, which are well suited for hunting large prey, might become a hindrance when times are tough, prey are rare, and individuals have to work harder to find their next meal.

Dr Philip Stephens, from the School of Biological and Biomedical Sciences, Durham University, said: "We found that the largest species exhibited a five to six fold greater decrease in relative abundance in response to a decrease in their prey.