Dogs and Cats
Dogs
The term "domestic dog" refers to any of several hundred breeds of dog in the world today. While these animals vary drastically in appearance, every dog—from the Chihuahua to the Great Dane—is a member of the same species, Canis familiaris. This separates domestic dogs from wild canines, such as coyotes, foxes, and wolves.
Domestic dogs are mostly kept as pets, though many breeds are capable of surviving on their own, whether it’s in a forest or on city streets. A third of all households worldwide have a dog, according to a 2016 consumer insights study. This makes the domestic dog the most popular pet on the planet.
All dogs descend from a species of wolf, but not the gray wolf, like many people assume. In fact, DNA evidence suggests that the now-extinct wolf ancestor to modern dogs was Eurasian. However, scientists are still working to understand exactly what species gave rise to dogs.
The dog was the first species to be domesticated by humans. Experts estimate that hunter-gatherers domesticated dogs more than 15,000 years ago, which was before the development of agriculture. Due to their long association with humans, dogs have expanded to a large number of domestic individuals and gained the ability to thrive on a starch-rich diet that would be inadequate for other canids.
The dog has been selectively bred over millennia for various behaviors, sensory capabilities, and physical attributes. Dog breeds vary widely in shape, size, and color. They perform many roles for humans, such as hunting, herding, pulling loads, protection, assisting police and the military, companionship, therapy, and aiding disabled people.
Over the millennia, dogs became uniquely adapted to human behavior, and the human–canine bond has been a topic of frequent study. This influence on human society has given them the sobriquet of "man's best friend."
People have been breeding dogs since prehistoric times. The earliest dog breeders used wolves to create domestic dogs. From the beginning, humans purposefully bred dogs to perform various tasks. Hunting, guarding, and herding are thought to be among the earliest jobs eagerly performed by the animal destined to be called "man’s best friend."
For thousands of years, humans bred dogs toward the physical and mental traits best suited for the work expected of them. The sleek Greyhound types bred to chase fleet-footed prey, and the huge mastiff types used as guard dogs and warriors, are two ancient examples of dogs bred for specific jobs.
Cats
The domestic cat (Felis catus) is a small, typically furry, carnivorous mammal. They are often called house cats when kept as indoor pets or simply cats when there is no need to distinguish them from other felids and felines. Cats are valued by humans for companionship and their ability to hunt vermin.
Cats have been associated with humans for at least 9,500 years, and they are currently the most popular pet in the world. There are more than 70 cat breeds recognized by various cat registries.
Cats are similar in anatomy to the other felids, with strong, flexible bodies, quick reflexes, sharp retractable claws, and teeth adapted to killing small prey. They are predators that are most active at dawn and dusk. Cats can hear sounds too faint or too high in frequency for human ears, such as those made by mice and other small animals. They can see in near darkness. Like most other mammals, cats have poorer color vision and a better sense of smell than humans.
Despite being solitary hunters, cats are a social species, and cat communication includes the use of a variety of vocalizations (meowing, purring, trilling, hissing, growling, and grunting), as well as cat pheromones and types of cat-specific body language.
Cats have a high breeding rate. Under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by neutering, as well as the abandonment of pets, has resulted in large numbers of feral cats worldwide, requiring population control.
In certain areas, this has contributed, along with habitat destruction and other factors, to the extinction of many bird species. Cats have been known to extirpate a bird species within specific regions and may have contributed to the extinction of isolated island populations. Cats are thought to be primarily responsible for the extinction of 87 species of birds, and the presence of feral and free-ranging cats makes some otherwise suitable locations unsuitable for attempted species reintroduction.