The Evolution of Cattle
The Domestication and Migration of Cattle
Taurine
Indicine
Taurine cattle, Bos taurus, were domesticated in the Fertile Crescent in 10,500 BC by taming a small effective population of about 80 wild Aurochs. These cattle then migrated worldwide, primarily in correlation with the movement and settlements of early farmers. Increased geographical distances between populations created phenotypic plasticity and adaptions to different regions. For example, when Spanish colonists brought Taurine cattle to America, they were allowed to run free for about 400 years. During this period, the populations experienced natural selection rather than artificial selection, which helped increase the frequency of disease resistance traits and improved adaptation to the in harsh western landscapes.
Zebu, Bos indicus, were domesticated in the Indus Valley in 8000 BC. These cattle populations eventually spread to tropical zones of most continents. Zebu are hardy animals that have adapted to drought and low feed availability by having lower metabolic rates, many large sweat glands, a large skin surface, muscles instead of fat, and a short smooth coat.
We now know modern cattle evolved from Aurochs, but how? Researchers have completed principle component analysis and admixture tests, which show genetic differentiation between groups of modern cattle. These results are consistent with the idea of two separate domestication events into two existing taxa: indicine cattle and taurine cattle.
The size and aggression of Aurochs would have made capturing and domesticating these animals very difficult. This is why people started selecting for certain traits (smaller sizes and docility) almost immediately. Although these people probably knew nothing about genes, they selected traits that were favorable to them and noticed the offspring carried those traits.
1. Domesticated in the Fertile Crescent (10,500 BC)
2. Spread to western Anatolia and Aegean (7000 BC)
3. Spread simultaneously along Danube River in SE Europe and along the Mediterranean Coast to Africa (6400 BC)
4.Spread across Europe (5500 to 4100 BC)
5. Hybridization in Africa (500 AD)
6. Export of European and Italian breeds to North America by Spanish colonists (1400 AD)
Migration of Taurine Cattle
1. Domesticated in the Indus Valley (8000 BC)
2. Spread east to China, Indochina, and Indonesia
3. Moved west to SW Asia and Africa (4000 BC)
4. Hybridization in Africa (500 AD)
5. Spread to South America
Migration of Indicine Cattle
Indicine
Flat Back
Humped Back
Upright Ears
Floppy Ears
Estimated population: 600 Million
Estimated population: 720 Million
Distribution: Worldwide
Distribution: Tropical Zones
Distinctive Traits: leaner, muscular, adapted to hot climates
Distinctive Traits: draught power and adapted to heat, humidity, parasites, and poor quality forage