The first human ancestor existed on earth between five and seven million years ago. Throughout the lengthy process of evolution, humans acquired many skills, such as language, art, and the ability to build tools. One catalyst for the development of human civilizations is the domestication of animals and plants. The history of human civilizations and animal domestication are intimately intertwined which ultimately shifted humans from migratory lifestyles to settled living patterns.
The story begins over 15,000 years ago when an ancestor of the dog became the first animal that was domesticated by humans. This inevitably resulted in the evolution of the common domestic dog species. It has been argued that without dogs, humans cannot domesticate other animals and there will be no civilization. This is due to the loyal characteristic of dogs and, only with their help, can humans manage herds of other animals. Although some may view this argument to be exaggerating the role of dogs on human evolution, this statement emphasizes that the domestication of dogs played an important role in human evolution and the advancement of human civilizations. Other studies also proposed the idea that dogs and humans co-evolved together by sharing similar social-communicative skills. Evidence to support this suggests that modern dogs have the skills to discriminate human emotional expressions from human body language. A 2015 study found that extensive eye contact between dogs and their owners resulted in increased oxytocin secretion in both participants. As oxytocin is known for its role in maternal bonding and during positive social interactions, this is considered as evidence for co-evolution of human-dog bonding.
With the help of dogs, humans entered the first phase of evolution. During the first phase of human evolution, domestication of animals allowed extension of tool making for humans and allowed humans to gather knowledge about animals. This allowed humans to transition to the second phase of evolution which was to use domesticated animals and plants as renewable resources and also using animals as living tools. The first animals domesticated by humans as a source of food occurred between 11,000 and 9,000 BC in Southwest Asia and are thought to be sheep and goats. These animals were used for their meat, milk, and coat. Domestication of cattle, pigs, and horses shortly followed.
Traits of candidates for domestication:
- Grow and mature quickly, efficient for farming
- Breed under captivity. Wild ancestors have strict seasonal reproduction and molting rhymes while most domesticated animals can reproduce any season in the year under captivity.
- Herbivores, plant-based diets to minimize cost
- Hardy and able to adapt to different environments
- Live in herds which makes them easy for humans to control
Then vs. Now
One can imagine, current domesticated animals are quite different from their wild ancestors. An example of such is the chicken. Wild chickens weighed around two pounds and hatched small numbers of eggs once a year. Today, domestic chickens can weigh as much as 17 pounds and lay more than 200 eggs each year. The domestication of dogs is another example of the benefits of artificial selection. Currently there are over 400 breeds of domestic dog with drastically different physical traits and personalities. Dogs are diversely used in different sectors to help humans with various task such as search and rescue, hunting, and therapy. Different dog species are bred to enhance specific traits that are beneficial to humans. An example of such selection is seen in the Golden Retrievers and Labradors which are often selected as guide dogs due to their general trainability and calm temperaments.
The artificial breeding of animals not only changed the evolutionary path of selected animals, it also reversely selected humans with strong observational skills, communication skills, and those with the ability to form connections with animals. These skills helped humans to preadapt to live in higher densities and more permanent settlements. This can explain why humans now can form these close connections with different animals. Since managing and tracking animals requires knowledge and ways to preserve and convey information, the domestication of animals has been shown to be a direct cause of humans developing language and figurative art skills. Paleoanthropologist Pet Shipman of The Pennsylvania State University has shown that nearly all the earliest prehistoric artworks depicted animals, showing the importance of preserving information of animals during human evolution.
The connection between human and animals served a great role in human evolution and civilization. Domestication of animals provided humans with the ability to adapt to different environments and shifted the existing migratory lifestyle to a more settled lifestyle. Animals and plants not only provided stable resources for humans, they also expanded human cognitive processes and furthered the development of human language and art. Considering the positive impact of animals on human evolution, it is important for humans to think about our actions regarding animal welfare and the overexploitation of our environment. Since our life and animals are intertwined, we need to put more effort on protecting endangered and threatened animal species while continuing to ensure proper care for domesticated animal species.
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