Alternative Titles: Islamic Republic of Iran, Jomhūrī-ye Eslāmī-ye Īrān
Soil patterns vary widely. The abundant subtropical vegetation of the Caspian coastal region is supported by rich brown forest soils. Mountain soils are shallow layers over bedrock, with a high proportion of unweathered fragments. Natural erosion moves the finer-textured soils into the valleys. The alluvial deposits are mostly chalky, and many are used for pottery. The semiarid plateaus lying above 3,000 feet (900 metres) are covered by brown or chestnut-coloured soil that supports grassy vegetation. The soil is slightly alkaline and contains 3 to 4 percent organic material. The saline and alkaline soils in the arid regions are light in colour and infertile. The sand dunes are composed of loose quartz and fragments of other minerals and, except where anchored by vegetation, are in almost constant motion, driven by high winds.
Iran’s climate ranges from subtropical to subpolar. In winter a high-pressure belt, centred in Siberia, slashes west and south to the interior of the Iranian plateau, and low-pressure systems develop over the warm waters of the Caspian Sea, the Persian Gulf, and the Mediterranean Sea. In summer one of the world’s lowest-pressure centres prevails in the south. Low-pressure systems in Pakistan generate two regular wind patterns: the shamāl, which blows from February to October northwesterly through the Tigris-Euphrates valley, and the “120-day” summer wind, which can reach velocities of 70 miles (110 km) per hour in the Sīstān region near Pakistan. Warm Arabian winds bring heavy moisture from the Persian Gulf.
Elevation, latitude, maritime influences, seasonal winds, and proximity to mountain ranges or deserts play a significant role in diurnal and seasonal temperature fluctuation. The average daytime summer temperature in Ābādān in Khūzestān province tops 110 °F (43 °C), and the average daytime winter high in Tabrīz in the East Āz̄arbāyjān province barely reaches freezing. Precipitation also varies widely, from less than 2 inches (50 mm) in the southeast to about 78 inches (1,980 mm) in the Caspian region. The annual average is about 16 inches (400 mm). Winter is normally the rainy season for the country; more than half of the annual precipitation occurs in that three-month period. The northern coastal region presents a sharp contrast. The high Elburz Mountains, which seal off the narrow Caspian plain from the rest of the country, wring moisture from the clouds, trap humidity from the air, and create a fertile semitropical region of luxuriant forests, swamps, and rice paddies. Temperatures there may soar to 100 °F (38 °C) and the humidity to nearly 100 percent, while frosts are extremely rare. Except in this region, summer is a dry season. The northern and western parts of Iran have four distinct seasons. Toward the south and east, spring and autumn become increasingly short and ultimately merge in an area of mild winters and hot summers.
Plant and animal life
Topography, elevation, water supply, and soil determine the character of the vegetation. Approximately one-tenth of Iran is forested, most extensively in the Caspian region. In the area are found broad-leaved deciduous trees—oak, beech, linden, elm, walnut, ash, and hornbeam—and a few broad-leaved evergreens. Thorny shrubs and ferns also abound. The Zagros Mountains are covered by scrub oak forests, together with elm, maple, hackberry, walnut, pear, and pistachio trees. Willow, poplar, and plane trees grow in the ravines, as do many species of creepers. Thin stands of juniper, almond, barberry, cotoneaster, and wild fruit trees grow on the intermediate dry plateau. Thorny shrubs form the ground cover of the steppes, while species of Artemisia (wormwood) grow at medium elevations of the desert plains and the rolling country. Acacia, dwarf palm, kunar trees (of the genus Ziziphus), and scattered shrubs are found below 3,000 feet (900 metres). Desert sand dunes, which hold water, support thickets of brush. Forests follow the courses of surface or subterranean waters. Oases support vines and tamarisk, poplar, date palm, myrtle, oleander, acacia, willow, elm, plum, and mulberry trees. In swamp areas reeds and grass provide good pasture.
Wildlife includes leopards, bears, hyenas, wild boars, ibex, gazelles, and mouflons, which live in the wooded mountains. Jackals and rabbits are common in the country’s interior. Wild asses live in the kavīrs. Cheetahs and pheasants are found in the Caspian region, and partridges live in most parts of the country. Aquatic birds such as seagulls, ducks, and geese live on the shores of the Caspian Sea and the Persian Gulf, while buzzards nest in the desert. Deer, hedgehogs, foxes, and 22 species of rodents live in semidesert, high-elevation regions. Palm squirrels and Asiatic black bears are found in Baluchistan. Tigers once inhabited the forests of the Caspian region but are now extinct.
Studies made in Khūzestān province and the Baluchistan region and along the slopes of the Elburz and Zagros mountains have revealed the presence of a remarkably wide variety of amphibians and reptiles. Examples are toads, frogs, tortoises, lizards, salamanders, racers, rat snakes (Ptyas), cat snakes (Tarbophis fallax), and vipers.
Some 200 varieties of fish live in the Persian Gulf, as do shrimps, lobsters, and turtles. Sturgeon, the most important commercial fish, is one of 30 species found in the Caspian Sea. It constitutes a major source of export income for the government, in the production of caviar. Mountain trout abound in small streams at high elevations and in rivers that are not seasonal.
The government has established wildlife sanctuaries such as the Bakhtegān Wildlife Refuge, Tūrān Protected Area, and Golestān National Park. The hunting of swans, pheasants, deer, and a number of other animals and birds is prohibited.
Iran is a culturally diverse society, and interethnic relations are generally amicable. The predominant ethnic and cultural group in the country consists of native speakers of Persian. But the people who are generally known as Persians are of mixed ancestry, and the country has important Turkic and Arab elements in addition to the Kurds, Baloch, Bakhtyārī, Lurs, and other smaller minorities (Armenians, Assyrians, Jews, Brahuis, and others). The Persians, Kurds, and speakers of other Indo-European languages in Iran are descendants of the Aryan tribes that began migrating from Central Asia into what is now Iran in the 2nd millennium BCE. Those of Turkic ancestry are the progeny of tribes that appeared in the region—also from Central Asia—beginning in the 11th century CE, and the Arab minority settled predominantly in the country’s southwest (in Khūzestān, a region also known as Arabistan) following the Islamic conquests of the 7th century. Like the Persians, many of Iran’s smaller ethnic groups chart their arrival into the region to ancient times.
The Kurds have been both urban and rural (with a significant portion of the latter at times nomadic), and they are concentrated in the western mountains of Iran. This group, which constitutes only a small proportion of Iran’s population, has resisted the Iranian government’s efforts, both before and after the revolution of 1979, to assimilate them into the mainstream of national life and, along with their fellow Kurds in adjacent regions of Iraq and Turkey, has sought either regional autonomy or the outright establishment of an independent Kurdish state in the region.
Also inhabiting the western mountains are seminomadic Lurs, thought to be the descendants of the aboriginal inhabitants of the country. Closely related are the Bakhtyārī tribes, who live in the Zagros Mountains west of Eṣfahān. The Baloch are a smaller minority who inhabit Iranian Baluchistan, which borders on Pakistan.
The largest Turkic group is the Azerbaijanians, a farming and herding people who inhabit the border provinces in the northwestern corner of Iran. Two other Turkic ethnic groups are the Qashqāʾī, in the Shīrāz area to the north of the Persian Gulf, and the Turkmen, of Khorāsān in the northeast.
The Armenians, with a different ethnic heritage, are concentrated in Tehrān, Eṣfahān, and the Azerbaijan region. A community of Georgians is centred on and around the city of Fereydūnshahr, in Eṣfahān province. A few isolated groups speaking Dravidian dialects are found in the Sīstān region to the southeast.
Semites—Jews, Assyrians, and Arabs—constitute only a small percentage of the population. The Jews trace their heritage in Iran to the Babylonian Exile of the 6th century BCE and, like the Armenians, have retained their ethnic, linguistic, and religious identity. Both groups traditionally have clustered in the largest cities. The Assyrians are concentrated in the northwest, and the Arabs live in Khūzestān as well as in the Persian Gulf islands.
Although Persian (Farsi) is the predominant and official language of Iran, a number of languages and dialects from three language families—Indo-European, Altaic, and Afro-Asiatic—are spoken.
Roughly three-fourths of Iranians speak one of the Indo-European languages. Slightly more than half the population speak a dialect of Persian, an Iranian language of the Indo-Iranian group. Literary Persian, the language’s more refined variant, is understood to some degree by most Iranians. Persian is also the predominant language of literature, journalism, and the sciences. Less than one-tenth of the population speaks Kurdish. The Lurs and Bakhtyārī both speak Lurī, a language distinct from, but closely related to, Persian. Armenian, a single language of the Indo-European family, is spoken only by the Armenian minority.
The Altaic family is represented overwhelmingly by the Turkic languages, which are spoken by roughly one-fourth of the population; most speak Azerbaijanian, a language similar to modern Turkish. The Turkmen language, another Turkic language, is spoken in Iran by only a small number of Turkmen.
Of the Semitic languages—from the Afro-Asiatic family—Arabic is the most widely spoken, but only a small percentage of the population speaks it as a native tongue. The main importance of the Arabic language in Iran is historical and religious. Following the Islamic conquest of Persia, Arabic virtually subsumed Persian as a literary tongue. Since that time Persian has adopted a large number of Arabic words—perhaps one-third or more of its lexicon—and borrowed grammatical constructions from Classical and, in some instances, colloquial Arabic. Under the monarchy, efforts were made to purge Arabic elements from the Persian language, but these met with little success and ceased outright following the revolution. Since that time, the study of Classical Arabic, the language of the Qurʾān, has been emphasized in schools, and Arabic remains the predominant language of learned religious discourse.
Before 1979, English and French, and to a lesser degree German and Russian, were widely used by the educated class. European languages are used less commonly but are still taught at schools and universities.