A team of researchers has created a phylogenetic tree of ruminants by sequencing the genomes of 44 species of ruminants, thus deciphering the evolutionary history of a large number of ruminants  The results reveal that ruminant populations declined significantly around 100,000 years ago, and that these declines coincided with the migration of humans out of Africa
This has been suggested as evidence that early human activity contributed to the decline of ruminant populations
During the same period, the population of horses, donkeys and other odd-toed ungula animals also declined significantly