Cow could becomes the only largest mammals left on the land: report

Based on continuing trend of size-biased extinctions of mammoths, sloths and saber-toothed tigers over the past 125,000 years, cows might be the largest mammals left on Earth in 200 years, American researchers have warned. Researchers pointed out that average mass of North American mammals shrunk from 200 to 15 pounds in last 11,000 years due to human activities like hunting.