They are generally not liked by many of us because of their dirty habits. We are talking about pigs. Domestic pigs belong to the genus Sus and family Suidae which comprises even-toed ungulates. Pigs are omnivorous in habit. Though they are famous for gluttony nature but they are social and intelligent mammals. Pig and hog are the common names used for the domestic pigs. Some scientists consider domestic pigs and wild boars as similar species. Pigs are characterized by a snout for nose, small eyes, a small tail which may be curled or straight. Body is thick with short legs provided with coarse hairs. Four toes are present on each foot with two large middle ones are used for walking.
Breeding period continues throughout the year in tropical regions but the maximum percentage of births has been noticed during the rainy season. A female pig is capable of giving birth to the young ones at the age of 8-18 months. Estrus cycle will then commence after an interval of every 21 days if she fails to breed. Male pigs become sexually mature at the age of 8-10 months. A litter of piglets is composed of 6-12 piglets. Under the conditions of severe stress pigs can eat their own young ones. Pigs lack functional sweat glands so they keep their bodies cool by submerging it in water or mud during the summer season. Mud is also used as a sunscreen to protect the body from sunburn. Mud also provides protection against the flies and the parasites. Head is generally large with a long snout provided with a specialized prenasal bone demarcated by the presence of cartilage at its tip. Snout is used for digging in soil and in finding food. It is a very useful sensory organ. There are 44 teeth in the mouth of pigs. Canine are also called as tusks, grow continuously. They are sharpened by continuous rubbing of canines of both upper and lower jaws.
Around 2 billion species of animals are alive in the modern world of which domesticated pig is one of the most frequent in occurrence. Apart from the domesticated species wild boar is also found in good numbers on earth. Its many subspecies are most commonly found in Eurasia and its islands, from Ireland and India to Japan and north to Siberia. Some commonly occurring species of pigs include wild boars, bearded pigs and warty pigs. Man has introduced pigs in Australia, North and South America. Domestic pigs are reared as livestock by the farmers for the purpose of meat and leather. The bristly hairs are used for making brushes. Some species are also kept as pets like the Asian pot-bellied pig. A close watch is kept over the domestic pigs by swineherds. Pigs are excellent in foraging activity and their sense of smell is excellent so they are used in finding truffles in many European countries. They feed on both plant and animal stuffs indicating that they are omnivores. In wild they feed on leaves, grasses, roots, fruits and flowers.
Pigs have been domesticated since a long time in the Old World. Archaeological evidence suggests that the management of pigs in the olden times followed the same procedure as is used by the modern farmers. Wild boars were domesticated by the New Guineans as early as 13,000-12,700 BP in the near East and the Tigris Basin. A separate technique of domestication of pigs was later on given by China. In India pigs have been domesticated since times immemorial in Goa and other rural areas especially for the pig toilets. Pig toilets are used in the septic tanks. Pigs have reached Europe and southeastern North America by a Spanish traveler Hernando de Soto. They are highly valued in China and other neighbouring islands. Domesticated pig is designated by the scientific name Sus scrofa while others call it S. domesticus and the term S. scrofa is allotted to the wild boar. The domestication of S. domesticus began 5,000-7,000 years ago. Their body covering is coarse and bristly. They are brown are in colour but become grey as they grow old. Head ranges in size from 0.9-1.8 m in length and the body weight averages 50-350 kg.
They are intelligent animals and can be trained for certain tasks and tricks. The dwarf breeds are kept as pets in houses. They deserve a special place in culture and religion. Domestic pigs that have escaped from farms and the wild boars that were introduced in the forests as prey for hunting have given rise to a large population of the feral pigs in North and South America, Australia, New Zealand and other areas where pigs were earlier absent. The uprooting of plants by pigs in forests has shaken the ecological balance. They eat small animals and destroy the nests of ground dwelling birds. They are houses of a number of parasites and diseases that are transmitted to humans. These include cysticercosis, trichinosis and brucellosis. They are known to carry a number of parasitic worms inside their digestive tract. The flesh of pigs containing these parasites causes diseases in humans. So before the consumption of pig flesh proper care should be taken. They are also susceptible to bronchitis and pneumonia as the lungs are very small in size as compared to the body so these diseases can kill the pig. They also act as reservoirs of viruses like the swine flu virus and the influenza virus. They can become aggressive if disturbed resulting in severe injuries on the victim’s body.
It is now very clear that pigs are social animals so should be hated as they are very valuable to human beings.