The world’s plant-eating giants—including hippopotamuses, elephants, rhinoceros, and gorillas—are being rapidly wiped from the Earth, warns a new scientific study, and if habitat loss and human hunting continue unabated, these iconic species will be replaced with an “empty landscape.”

The study——was published Friday in the journal Science Advances by a global team of wildlife ecologists headed by William Ripple, professor at Oregon State University.

According to the research, 60 percent of the largest herbivores on the planet already face the immediate threat of extinction.

Focusing on 74 species of plant-eating giants, the researchers came to the conclusion that “large herbivores (and many smaller ones) will continue to disappear from numerous regions with enormous ecological, social, and economic costs. We have progressed well beyond the empty forest to early views of the ’empty landscape’ in desert, grassland, savanna, and forest ecosystems across much of planet Earth.”