The Critical Role and Limited Species of Large Domestic Mammals

Key Insight

Big domestic mammals were indispensable to human societies, providing a diverse array of resources. They supplied meat and milk products, served as sources of fertilizer, offered land transport, contributed leather, functioned as military assault vehicles, enabled plow traction, and yielded wool. Furthermore, these animals were vectors for germs that significantly impacted previously unexposed human populations. While smaller animals like dogs, chickens, rabbits, and even insects like honeybees and silkworms were also valuable for food, hunting, or materials, none offered the comprehensive utility and large-scale impact of big domestic mammals for heavy labor, transport, or primary food production.

Of the world's large terrestrial herbivores, defined as species weighing over 100 pounds, a surprisingly small number—only 14—were domesticated before the twentieth century. These 'Ancient Fourteen' are divided into two groups. The 'Major Five' species—the cow, sheep, goat, pig, and horse—became globally widespread and profoundly important. The remaining 'Minor Nine'—including the Arabian camel, Bactrian camel, llama/alpaca, donkey, reindeer, water buffalo, yak, banteng, and gaur—were significant livestock in more geographically restricted areas. Notably, the pig is an omnivore, distinguishing it from the other 13 strictly herbivorous species among the Ancient Fourteen.

The wild ancestors of 13 of these Ancient Fourteen species, encompassing all of the Major Five, were concentrated in Eurasia (which includes North Africa for biogeographical reasons). In stark contrast, South America contributed only one ancestral species (giving rise to the llama and alpaca), while North America, Australia, and sub-Saharan Africa had none. This uneven geographical distribution of domesticable wild ancestors was a major factor in the historical advantages gained by Eurasian peoples. Eurasia possessed the greatest number of candidate species for domestication due to its large landmass and ecological diversity, and it experienced fewer large mammal extinctions in the last 40000 years compared to the Americas and Australia.