Evolution of domestic goats

Billy Goat

Goat evolution is how domestic goats came to existence through natural selection transition. Wild goats were reportedly one of the first species domesticated by humans, with the time of domestication is generally estimated to be around 8,000 BCE.

Domestic goats are medium-sized mammals that are found in harsh environments, mainly mountains and forests, in Central Asia and the Middle East, covering an area from Turkmenistan to Turkey. Goats are an extensive part of the family Bovidae, a populous and broad group that includes various ruminants such as cows, bison, and also sheep. Bovids all share many traits, such as a herbivorous diet, hooves, and all males and some females with visible horns. Bovids began to deviate from deer and giraffids during the early Miocene epoch. The subfamily Caprinae, which includes ibex, goats, and sheep, are considered to have deviated from the other Bovidae as early as the Miocene, with the group attaining its most incredible diversity in the ice ages.

Evolution of the Bovidae family

The closest relatives of bovids are giraffids and cervids, which the group isolated from early in its evolutionary lineage. It is commonly believed that bovids separated from giraffids and deer nearly 20 million years ago, in the early days of the Miocene epoch. These bovids were likely to have happily lived in the Old World’s woodland environments and were small in size and deer-like.

The earliest recognized Bovid was Eotragus, a genus of short antelope-like animals nearly related to the four-horned antelope and modern nilgai and lived over much of Eurasia. Although little is known about Eotragus, many of the traits unique to modern bovids have been seen, including crowned teeth. Crowned teeth are assumed to have evolved to handle tougher vegetation that Eotragus may have been exposed to in the forest. The traits would consequently carry over to the plains, resulting in bovids becoming proficient at processing various grass and their authority in open environments. Horns have also been seen in Eotragus fossils and were likely used in males to attract mates and assert dominance, similar to modern bovids. It is also possible they doubled a fierce weapon against wild predators.

Eotragus, a small deer-like mammal, is the earliest known bovid genus

Hooves were also existing in these early bovids, similar in function and form to modern bovids’ claws. As Eotragus lived in woodland environments, it remained small compared to many modern bovids. While absentt in the earliest bovid species, the large size of many Bovidae’s modern family members became evident in animals found soon after Eotragus as members began to occupy more open environments such as savannah and grasslands.

Early in the family’s natural history, there was a deviation into the Aegodontia and Boodontia clades, which are from Eurasia and Africa, respectively. This divergence is attributed to a temporary continental divide between the two landmasses. The two clades began to synchronize after the continents were later rejoined, as the geographic split disappeared. Modern goats are descended from Aegodontia, including all bovids outside the subfamily Bovinae. Generally, modern bovids differ heavily in their behavior, such as their sociability, with some going in groups and others being solitary. Hence, little can be concluded about these early bovids’ behavior, leaving it nearly unstudied.

Miocene period

About 15 million years ago, during the Miocene epoch, the family Bovidae had expanded into around 15 different genera, mostly concentrated in Asia. Following this, the family’s diversity improved dramatically, and by the end of the Miocene, a total of 70 genera are said to have survived. The Bovidae’s success is generally attributed to their capacity to rapidly move across plains and cope with the raw grass found in them due to their evolved teeth. 

The wealth of grassland in Asia, which served ancient bovids considerably, is usually considered to be the reason for the more tremendous success of the family in Asia. However, many species also performed well in Africa. During this rapid diversification period in the mid-late Miocene, the Caprinae deviated from the other Bovidae. These early Caprids are generally thought to have resembled the Serow, a genus of medium-sized goat-like mammals.

Caprids were forced to find their corner away from the plains, which were already heavily populated by Deer (Cervidae). They thus increased the natural agility required to live in harsh environments. The habitats occupied by several caprids species would differ noticeably, and members of the group have since been found in areas ranging from the tundra, deserts, and alpine environments. However, their universal dependence on more rigid environments meant that the subfamily was much more prosperous in Asia than Africa, as were many other bovid groups.

Domestication of Goats

Although estimates vary, it is believed that goats were first domesticated around 9,500–9,900 years ago. This occurred in southeastern Anatolia, although separate domestication instances happened in Iran about 6,500 years ago and in eastern Turkey nearly 2,500 years ago. Today, the bulk of domesticated goats are descended from the latte. Other domestication evidence can be seen in Western Asia, recorded about 8,000 years ago.

Early goat domestication provided milk, meat, fuel, and clothing for neolithic farmers, and their remains could also have been used to build weapons and shelters. The domestication process has swiftly increased both the speed of evolutionary improvement and the genetic diversity of the goats from different regions, with their currently being recorded 300 breeds catered for various purposes.

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