For more than 12,000 years it has lived with humans as a hunting companion, protector, object of scorn or adoration, and friend. The dog evolved from the gray wolf into more than 400 distinct breeds. Human beings have played a major role in creating dogs that fulfill distinct societal needs. Dogs are regarded differently in different parts of the world. Characteristics of loyalty, friendship, protectiveness, and affection have earned dogs an important position in Western society, and in the United States and Europe the care and feeding of dogs has become a multibillion-dollar business. Western civilization has given the relationship between human and dog great importance, but, in some of the developing nations and in many areas of Asia, dogs are not held in the same esteem. In some areas of the world, dogs are used as guards or beasts of burden or even for food, whereas in the United States and Europe dogs are protected and admired. In ancient Egypt during the days of the pharaohs, dogs were considered to be sacred.

Despite the close association between dogs and humans, dog attacks on humans are fairly common. Between 1982 and 2013, some 466 people were killed by dogs in Canada and the United States. Over the same period, there were more than 4,100 dog attacks in the region, which resulted in more than 2,400 cases of maiming.

Lions prey on a large variety of animals ranging in size from rodents and baboons to water buffalo and hippopotamuses, but they predominantly hunt medium- to large-sized hoofed animals such as wildebeests, zebras, and antelopes. Prey preferences vary geographically as well as between neighboring prides. Lions are known to take elephants and giraffes, but only if the individual is young or especially sick. They readily eat any meat they can find, including carrion and fresh kills that they scavenge or forcefully steal from hyenas, cheetahs, or wild dogs. Lionesses living in open savanna do most of the hunting, whereas males typically appropriate their meals from the female’s kills. However, male lions are also adept hunters, and in some areas they hunt frequently. Pride males in scrub or wooded habitat spend less time with the females and hunt most of their own meals. Nomadic males must always secure their own food.

Though a group of hunting lions is potentially nature’s most formidable predatory force on land, a high proportion of their hunts fail. The cats pay no attention to the wind’s direction (which can carry their scent to their prey), and they tire after running short distances. Typically, they stalk prey from nearby cover and then burst forth to run it down in a short, rapid rush. After leaping on the prey, the lion lunges at its neck and bites until the animal has been strangled. Other members of the pride quickly crowd around to feed on the kill, usually fighting for access. Hunts are sometimes conducted in groups, with members of a pride encircling a herd or approaching it from opposite directions, then closing in for a kill in the resulting panic. The cats typically gorge themselves and then rest for several days in its vicinity. An adult male can consume more than 34 kg (75 pounds) of meat at a single meal and rest for a week before resuming the hunt. If prey is abundant, both sexes typically spend 21 to 22 hours a day resting, sleeping, or sitting, and hunt for only 2 or 3 hours a day.

Nature reported that 871 people in Tanzania were attacked by lions between 1990 and 2005. One of the most frightening series of attacks took place Kenya in 1898 in which two lions killed dozens of railway workers before the pair were shot. Between 1932 and 1947, perhaps as many as 1,500 people were killed by an aggressive pride of lions near the town of Njombe, Tanzania. Today, lions kill approximately 100 people per year in Tanzania.

Although clumsy in appearance, bears can move surprisingly fast, even through dense cover that would seriously impede a human or a horse. Their senses of sight and hearing, however, are poorly developed, and most hunting is done by smell. Some, such as black and spectacled bears, are strong climbers, and all are strong swimmers, most notably the polar bear. Bears do not generally communicate by sound and usually are quiet, but they do growl at times when feeding, when being challenged by another bear or by humans, and when competing for mates.

Except for the carnivorous polar bear and the vegetarian giant panda, bears are omnivorous, consuming many items that may seem small for an animal of such large size. Ants, bees, seeds of trees, roots, nuts, berries, insect larvae such as grubs, and even the dainty dogtooth violet are eaten. Many bears relish honey, and the sun bear is sometimes called the “honey bear” because of this. Prey taken by bears includes rodents, fish, deer, pigs, and seals. Grizzlies (North American subspecies of the brown bear, Ursus arctos) are known for their skillful fishing during the spawning runs of salmon. The polar bear’s diet is dictated by the Arctic environment, as little vegetation grows within its range. The Asian sloth bear (Melursus ursinus) delights especially in raiding and destroying termite nests, sucking up termites and larvae with its funnel-like lips. The giant panda has a special bone formation of the forefoot that functions as a sixth digit; it is opposable to the other five and thus is useful in handling bamboo.

If captured when young, bears can be tamed quite easily and are commonly used in circus animal acts. This has often caused people to consider bears as tame and harmless rather than as potentially dangerous creatures deserving wariness and respect. This mistake has frequently resulted in tragedy for both humans and bears. Grizzly and polar bears are the most dangerous, but Eurasian brown bears and American black bears have also been known to attack humans. Some species depredate livestock on occasion, and some bears, such as Asiatic and American black bears, may destroy fruit or other crops, especially corn.

Hippopotamus is Greek for “river horse,” and the animal has been known since ancient times. Hippopotamuses are often seen basking on the banks or sleeping in the waters of rivers, lakes, and swamps next to grasslands. The hippopotamus has a bulky body on stumpy legs, an enormous head, a short tail, and four toes on each foot. Each toe has a nail-like hoof.

Hippos are well adapted to aquatic life. The ears, eyes, and nostrils are located high on the head so that the rest of the body may remain submerged. The ears and nostrils can be folded shut to keep out water. The body is so dense that they can walk underwater, where they can hold their breath for five minutes. Although often seen basking in the sun, hippos lose water rapidly through the skin and become dehydrated without periodic dips. They must also retreat to the water to keep cool, for they do not sweat. Numerous skin glands release a pinkish “lotion,” which led to the ancient myth that hippos sweat blood; this pigment actually acts as a sunblock, filtering out ultraviolet radiation.

Accounts recording the number of human deaths per year by hippo attack range from about 500 to about 3,000. It is thought that hippo attacks on small boats are antipredator behavior, with the hippos mistaking them for crocodiles. As a result, hippos have long had a largely undeserved reputation as aggressive animals. Cows live in “schools,” but they are not permanently associated with other cows, though sometimes they maintain bonds with offspring for some years. Longevity is up to 49 years in captivity but rarely more than 40 in the wild.

The tiger is the largest member of the cat family (Felidae), rivaled only by the lion (Panthera leo) in strength and ferocity. Ranging from the Russian Far East through parts of North Korea, China, India, and Southeast Asia to the Indonesian island of Sumatra, all six remaining subspecies are endangered. The Siberian, or Amur, tiger (P. tigris altaica) is the largest, measuring up to 4 meters (13 feet) in total length and weighing up to 300 kg (660 pounds). The Indian, or Bengal, tiger (P. tigris tigris) is the most numerous and accounts for about half of the total tiger population.

Next to the elephant and the lion, no wild animal is so frequently portrayed in Asian art and lore. The persistent practices of using tiger parts as talismans, tonics, or medicine, despite all scientific evidence contrary to their efficacy, are manifestations of beliefs that emanate from the aura of the tiger and the awe that it has inspired for millennia. Certain animist communities still worship the tiger. Every 12th year of the Chinese calendar is the year of the tiger, and children born in it are considered especially lucky and powerful. In Hindu mythology the tiger is the vahana (“vehicle”) of the goddess Durga. Tigers are represented on seals from the ancient Indus civilization. The greatest of the Gupta emperors of ancient India, Samudra, minted special gold coins depicting him slaying tigers. Tippu Sultan even vented his frustration at his inability to defeat the British by ordering a special life-size toy, replete with sound, of a tiger mauling a British soldier.

In India, tigers have a history of attacking human visitors to zoos who either enter or place their hands into tiger enclosures. Tigers are also known to attack people in the wild, especially in the Sundarbans, a region of forests and swampland straddling the border between India and Bangladesh. By some accounts, 50 to 250 people per year are killed in the Sundarbans by tigers.

The relationship of the horse to humans has been unique. The horse is a partner and friend. It has plowed fields and brought in the harvest, hauled goods and conveyed passengers, followed game and tracked cattle, and carried combatants into battle and adventurers to unknown lands. It has provided recreation in the form of jousts, tournaments, carousels, and the sport of riding. The influence of the horse is expressed in the English language in such terms as chivalry and cavalier (coming from the Latin caballarius, "horseman"), which connote honor, respect, good manners, and straightforwardness.

The horse is the “proudest conquest of Man,” according to the French zoologist Georges-Louis Leclerc, comte de Buffon. Its place was at its master’s side in the graves of the Scythian kings or in the tombs of the pharaohs. Many early human cultures were centered on possession of the horse. Superstition read meaning into the colors of the horse, and a horse’s head suspended near a grave or sanctuary or on the gables of a house conferred supernatural powers on the place. Greek mythology created the centaur, the most obvious symbol of the oneness of horse and rider. White stallions were the supreme sacrifice to the gods, and the Greek general Xenophon recorded that “gods and heroes are depicted on well-trained horses.”

Despite being held in such high esteem, horses kill roughly 100 people in the United States each year in riding accidents and other equestrian-related activities. Matched against horse ridership (some 7 million or so), the risk of death is very small, however.

Worldwide, deer make up any of 43 species of hoofed ruminants in the order Artiodactyla, notable for having two large and two small hooves on each foot and also for having antlers in the males of most species and in the females of one species. Deer are native to all continents except Australia and Antarctica, and many species have been widely introduced beyond their original habitats as game animals. One species, the reindeer (also known as the caribou), has been domesticated. Some swamp and island species are endangered, but most continental species are flourishing under protection and good management. Deer, when granted some protection, readily exploit man-made disturbances caused by agriculture, forestry, and urbanization. White-tailed deer, normally a cherished North American game animal, have even become pests in suburbs and cities in the United States and Canada.

Still, deer are common residents in urban and suburban landscapes, and unwary deer frequently cause automobile accidents on roads. According to one major insurance provider, hundreds of thousands of deer-vehicle accidents happen in the United States each year, resulting in millions of dollars of damage to cars and trucks and about 200 deaths.

Elephants are the largest living land animals. They are known by their long trunk (elongated upper lip and nose), columnar legs, and huge heads with temporal glands and wide, flat ears. Elephants are grayish to brown in color, and their body hair is sparse and coarse. They are found most often in savannas, grasslands, and forests but occupy a wide range of habitats, including deserts, swamps, and highlands in tropical and subtropical regions of Africa and Asia. The three living species of elephants are related to prehistoric woolly mammoths and mastodons. The African savanna, or bush, elephant (Loxodonta africana) weighs up to 8,000 kg (9 tons) and stands 3 to 4 meters (10 to 13 feet) at the shoulder. The African forest elephant (Loxodonta cyclotis), which lives in rainforests, was recognized as a separate species in 2000 and is smaller than the savanna elephant. It has slender, downward-pointing tusks. The common belief that there existed “pygmy” and “water” elephants has no basis; they are probably varieties of the African forest elephants. The Asian elephant (Elephas maximus) weighs about 5,500 kg and has a shoulder height of up to 3.5 meters.

For many centuries the Asian elephant has been important as a ceremonial and draft animal. Technically, elephants have not been domesticated, for they have not been subjected to selective breeding for “improvement” of traits desired by humans, as has been the practice with cattle, horses, and dogs. Historical records of tamed Asian elephants date to the Indus civilization. At Mohenjo-daro and Harappa, Pakistan, soapstone carvings depict elephants with cloth on their backs, which indicates use by humans. Mahouts and oozies (elephant trainers in India and Myanmar, respectively) are skilled people who remain in direct contact with the animals for many years. The handlers take care of all the elephants’ needs, and the bond between man and beast becomes very strong. Hastividyarama, an age-old handbook for elephant tamers, spells out prescribed training procedures in detail and is still used today in some parts of Asia. Commanded by its mahout, the elephant was once basic to Southeast Asian logging operations. It remains a symbol of power and pageantry but has been largely supplanted by machinery. At the beginning of the 21st century, Thailand and Myanmar each had about 5,000 captive elephants employed in traditional roles intermingled with modern use as tourist attractions.

Human deaths due to elephants range from about 100 to more than 500 per year. Elephants have been known to raid villages or croplands in South Asia, and sometimes gore or step on humans that get in the way. Their sheer size and weight is enough to deliver a lethal blow from one strike.

Human beings are culture-bearing primates that are both anatomically similar and closely related to the other great apes. They are distinguished from other great apes by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning. In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition, as in anatomy, between humans and the other great apes (orangutans, gorillas, and chimpanzees) is much less than was once thought, as these primates have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans.

One thing that cannot be argued is that human beings are the world’s most efficient killers of other humans. Globally, an estimated 56 million people die per year when all causes of death are considered. Roughly 526,000 people are killed by armed violence. Roughly 75% of these deaths are classified as intentional homicides. In addition, some 54,000 humans succumb to unintentional violent deaths, and 55,000 people die per year as a result of war and terrorism.