Animal Domestication

In our insulated modern lives, it is difficult to appreciate the degree to which animal domestication transformed human life. Dogs worked as hunters and sentries and provided companionship. Cats reduced vermin populations and provided companionship. Somewhere between PPNA and and the end of PPNB, animal domestication made humans comparatively rich. Cattle, pigs, sheep, and goats converted grassland and domestically produced grain into food for humans. Next, horses and camels provided transportation and transport and oxen plowed fields. Sheep and cattle provided clothing. Birds became pets but also provided food, messaging, and hunting.

Animal domestication is the intentional breeding of animals over multiple generations to make them suitable as companions, work animals, sources of food, or sources of other products. Domestication is different from taming animals. Taming animals involves capturing wild animals and conditioning them with food to be under the control the humans, but these wild animals are not genetically disposed to live with humans, and their offspring will be no more suitable for living with humans than a wild animal offspring.

Pets and work animals

Dogs were the first domesticated animals. European hunter-gatherers made them useful partners in hunting and protection. They also became an important part of agricultural communities. Scientists think that dogs first separated from wolves when a group of wolves in Europe started following humans approximately 20,000 years ago or 3500 to 4000 dog generations ago. Those wolves that were naturally more adaptable to interaction with humans were the wolves that became domesticated. Thus, the initial domestication of the wolf was by natural selection. Subsequently, humans intentionally chose the breeding partners of selected wolves/dogs, which is artificial selection. Astoundingly, people eventually bred such varied breeds as the Maltese, dachshund, Scottish terrier, and St. Bernard from the original wolf. Even though they look different, they are still one species.

Selection for animal traits is accomplished by selecting mutants in a litter and then backcrossing with other animals in the litter in order to fix that trait. This is different from natural selection. Darwin thought that dogs were a good analog for natural selection, but this is not correct. All the differences between dogs are due to a few genes. For example, over 50% of the variation in body size among dogs is due to just one gene, IGF1. Other genes control coat color and pattern, leg length, fur type, and skull shape. In contrast, 40 genes in humans (natural selection) explain only 5% of the variation in humans.

The PPNA Natufians hunted with dogs and made them pets. The first evidence in the world of a dog as a pet was in a Natufian PPNA grave (11 ka) in which a lady was buried along with her dog.

Dogs probably have the cognition level of a 3-5-year-old human. This is based on several indications of intelligence. They can compare dog bowls and select the bowl with the most food. They recognize voices, and can determine friend or foe. They can detect hints in body language, smells and voice tones. They can feel optimism or depression, and anxiety and fear. They experience jealousy when another dog gets preferential treatment. Much of their intelligence might be due to the long association with humans and selective breeding. [1]

Cats domesticated themselves by entering the human community. The first domesticated cats were Eurasian wildcats. They probably fed on rats in early villages. [2]

The work animals, beasts of burden, provided much more energy for transportation and agriculture than a human could hope to provide. For example, an oxen provides the work of six humans in agriculture. Horses and camels carry humans, and horses and oxen pull various types of carts loaded with humans and supplies. It is sad, however, that horses were used as tools in war, which was an extremely abusive environment for humans and horses.

Animal husbandry

Most farm animals were domesticated in the Fertile Crescent. Mouflon wild sheep began to be domesticated in the Taurus Mountains in northern Iraq between 12,000 and 11,000 BP. Mouflon males had large horns in order to fight each other during mating season (Figure 14‑22), but this was not an optimal characteristic for domesticated sheep so this characteristic was gradually eliminated through selection. At first, people raised sheep primarily for meat and milk. The coarser fleece of the early sheep needed to be plucked from the animal rather than shorn. Breeding for long wool began about 4,000 years later (8,000 BP), and breeding for white wool began 3,000 years later (5,000 BP). Shortly after that, sheep began to look like modern sheep. Thus, it took over 8,000 years to breed modern sheep from the original Mouflon. Much later, the Spanish bred Merino sheep. It was so prized and protected that selling a Merino outside of Spain was punishable by death. Eventually, the Merino sheep spread around the world, and it is now the most popular breed of sheep.

Driscoll listed the “favorable and unfavorable ecological and behavioral preadaptations to domestication” for barnyard animals in Table 13-3 Some of the keys to domestication were that the herd should follow a dominant individual, they had to tolerate close quarters, they should be able to adjust to a range of diets, they should not be territorial, and they needed to be willing to breed around people. The animal should be docile and if it is raised for meat, then it should grow quickly. It should not be a meat eater because it is inefficient to feed meat to an animal in order to produce meat.

The earliest domesticated birds were pigeons. Pigeons (Figure 14‑22) were domesticated between 10,000 BP and 5,000 BP in the Fertile Crescent, but they were probably not intentionally domesticated. They are in the unfavorable column in almost every category in Table 13-3; however, they probably hung around human camps in search of food scraps. They eventually became domesticated for meat, and it turned out that they were great messengers, due to their eyesight, navigation, and memory of images. They also became popular pets (Figure 14‑23).

References

[1] Helen Ann Travis. Dog Brain Facts: Understanding Canine Cognition. Accessed on Mar 11, 2019 at <https://www.petmd.com/dog/behavior/dog-brain-facts-understanding-canine-cognition>

[2] Driscoll CA, et al. (2007) The Near Eastern origin of cat domestication. Science 317:519–523.

[3] Driscoll, From wild animals.

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Eurasian Wold. Credit: Mac3CF. Used here per CC BY-SA 4.0.