Zoology is the science that studies animals. Its classification is complex and can be done according to several factors : by its structure (vertebrates and invertebrates), by the type of feeding (herbivorous, carnivorous or omnivorous animals) or by its reproduction (oviparous or viviparous).
However, from a practical point of view there is another classification: wild animals and domestic animals. The former cannot be trained, nor can they coexist with humans. On the contrary, domestic animals are docile and do adapt to the human context.
Livestock is the human and economic activity most related to domestic animals. When humans knew how to control animals in herds and take advantage of their benefits, at that time they could settle and establish themselves in a community, without the need to practice nomadism . The domestic animals that were used in ancient times to obtain a material benefit are the same as today: cows, pigs, goats, sheep and chickens, mainly. These animals provided meat, but also milk, eggs, skins, etc. The case of the pig is curious, because it is a domestic animal, but the wild boar (which is very similar to the pig) is wild and is not used in livestock.
In the margin of the characteristic livestock animals in the family humans we live with pets, pets. The most common are the dog, the cat and some birds. The most significant is probably the dog, since there is a very close link between this animal and its family environment. Dogs offer companionship, security, and are used as a guide for the blind or for therapy in some situations.
The concept of a pet has expanded over time. Currently there are wild animals that live with people: snakes, iguanas, some reptiles, felines ... It is a respectable practice, but not without risks; both for health, safety, and for the balance of the species.
In urban life, domestic animals are acquiring a greater role. This can be seen through many examples: the proliferation of veterinary clinics, hairdressers, dog parks, hotels that accept pets, authorized beaches, etc. And do not forget that legislation is also beginning to recognize animal rights.