By: Ian Hill

Unlike what scientists originally thought, which is that predators are at high risk of extinction, new studies show that herbivores may be at higher risk.

One out of four plant-eaters around the world are considered threatened, endangered or vulnerable by the International Union for Conservation of Nature (IUCN).

A new study led by Trisha Atwood, who is the Utah State University Assistant of the Watershed Sciences, suggests that herbivores are in more danger of extinction than predators.

To start this study, the Utah State research team looked at the dietary patterns for mammals, birds, and reptiles. They then categorized this data into the trophic groups, which are predators, herbivores, and omnivores. After examining this data, the research team has arrived at an extinction risk of about 18 percent across the IUCN vulnerable species. They got this number by dividing the number of threatened species over the total amount of species in the study. Using this algorithm, herbivores were by far at the most at risk, with 25% appearing in the IUCN threatened species list. This is equivalent to around 300 herbivore species facing risks of extinction.

Another piece of evidence, aside from the Utah State study, is the historical evidence. These pieces of evidence highlight the fact that human activities have played a part in the disproportionate extinction of herbivores starting from 11,000 to 50,000 years ago. There are patterns of extinction risk across habitats and trophic groups.