The Western Ghats, also called the Sahyadri, is a mountain range that extends 1,600 km (990 mi) along the western coast of the Indian peninsula. It covers an area of 160,000 km (62,000 mi) and spans the Indian states of Gujarat, Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu. The range forms a nearly continuous line of mountains along the western edge of the Deccan Plateau, starting near the Tapti River and ending at Swamithoppe in the Kanyakumari district, which is at the southern tip of the Indian peninsula. The Western Ghats meet the Eastern Ghats at Nilgiris before continuing south.

Geological evidence shows that the mountains formed during the break-up of the supercontinent Gondwana. This happened when India separated from Africa during the late Jurassic and early Cretaceous periods. The Western Ghats can be divided into three sections: the northern part, which has elevations between 900–1,500 m (3,000–4,900 ft); the middle section, which begins south of Goa and has elevations below 900 m (3,000 ft); and the southern part, where elevations rise again. Some peaks in the Western Ghats reach more than 2,000 m (6,600 ft), with Anamudi (2,695 m (8,842 ft)) being the highest. The average height of the range is about 1,200 m (3,900 ft).

The Western Ghats are a major area where water divides into different river systems. These rivers flow all year and drain nearly 40% of India’s land. Because the Deccan Plateau is higher on the west, most rivers flow eastward toward the Bay of Bengal, creating steep western slopes facing the Arabian Sea and gentler eastern slopes. The Western Ghats influence India’s climate by blocking monsoon winds from the Arabian Sea. This causes heavy rainfall along the western coast. By the time the air passes over the mountains, it becomes dry, leading to little rainfall on the leeward side toward the interior of the Deccan Plateau.

The Western Ghats are a biodiversity hotspot, meaning they are home to many unique species of plants and animals, most of which are found only in this region. At least 325 species worldwide are at risk of extinction and live in the Western Ghats. In 2012, the area was recognized as a UNESCO World Heritage Site.

Etymology

The name Western Ghats comes from the word "ghat" and the direction in which it is located compared to the Indian mainland. In the Indian subcontinent, the word "ghat" can mean either a group of stepped hills, such as the Eastern Ghats and Western Ghats, or a set of steps leading to a body of water or a wharf. According to linguist Thomas Burrow, the word "ghat" is believed to have originated from similar terms in Dravidian languages. These include "kattu" (meaning mountain side, ridge, or dam) in Tamil, "katte" (dam), "gatta" (mountain), and "gattu" (bank or shore) in Kannada, and "katta" (dam) and "gatte" (shore or embankment) in Telugu. The mountain range is also called Sahyadri, a name from Sanskrit that means "benevolent or tolerant mountain."

Geology

The Western Ghats are the mountainous, broken, and eroded edge of the Deccan Plateau. Geologic evidence shows that they formed during the splitting apart of the large landmass called Gondwana. After splitting apart, the Deccan Plateau was formed by hard rock layers, which made the western side rise higher.

Scientific studies show that the mountains formed along the west coast of India during the late Jurassic and early Cretaceous periods when India moved away from the African continent. Several faults caused the formation of the Western Ghats, which are mixed with valleys and river gorges. Because of the height of the Deccan Plateau on the west, most rivers flow from west to east, creating carved eastern slopes and more sloped western slopes facing the sea.

Geography

The Western Ghats stretch from the Satpura Range south of the Tapti River in the north and extend about 1,600 km (990 mi) to the southern tip of the Indian peninsula, ending at Marunthuvazh Malai in Swamithoppe, Kanyakumari district. They cover an area of 160,000 km² (62,000 sq mi) and pass through the Indian states of Gujarat, Maharashtra, Goa, Karnataka, Kerala, and Tamil Nadu.

The Western Ghats form a nearly continuous mountain range that runs parallel to India’s western coast along the Arabian Sea. Their average height is about 1,200 m (3,900 ft). There are three gaps in the range: the northernmost Goa Gap, formed about 65–80 million years ago; the oldest and widest Palghat Gap, formed 500 million years ago; and the southernmost, narrowest Shencottah Gap. The narrow coastal area between the Western Ghats and the Arabian Sea is called the Western Coastal Plains.

The mountains can be divided into three sections: the northern part, where elevations range from 900–1,500 m (3,000–4,900 ft); the middle section, starting south of Goa, with elevations below 900 m (3,000 ft); and the southern section, where elevations rise again. The Western Ghats meet the Eastern Ghats in the Moyar River valley in the Nilgiris before continuing south. Many peaks in the range rise above 2,000 m (6,600 ft), with Anamudi (2,695 m (8,842 ft)) being the highest.

The Western Ghats are one of India’s major watersheds, providing water to many rivers that flow year-round. These rivers drain nearly 40% of India’s land area. Major rivers that begin in the Western Ghats include the Godavari, Kaveri, and Krishna. Most rivers flow eastward toward the Bay of Bengal because the land slopes more steeply from east to west. Smaller streams also drain the region, often carrying large amounts of water during monsoons. These streams and rivers create many waterfalls. Dams have been built on the rivers for hydroelectric power and irrigation, with large reservoirs located throughout the area.

Climate

The Western Ghats have a major influence on India’s climate and seasons. During the dry summer months of April to May, heat builds up on the land, pulling air from the sea. This air picks up moisture as it moves eastward from the Arabian Sea but is stopped by the Western Ghats. As the air rises over the mountains, it cools and causes rain along the western coast, marking the start of the monsoon season in June. After passing over the mountains, the air becomes dry, creating a rain shadow region with little rainfall on the leeward side toward the interior of the Deccan plateau. Monsoon winds that curve around the peninsula and come from the Bay of Bengal move eastward, passing over the Eastern Ghats and bringing most of the rainfall to the northern plains.

The climate in the Western Ghats changes with altitude. Because the region is near the equator and the Arabian Sea, it has a warm and humid tropical climate year-round. Average temperatures range from 20°C (68°F) in the south to 24°C (75°F) in the north. Higher elevations experience cooler, subtropical or temperate climates, and sometimes near-zero temperatures in winter. The coldest months in the southern part of the mountain range are also the wettest. Annual rainfall in the region averages between 100 cm (39 in) and 900 cm (350 in), with an average of 250 cm (98 in). Rainfall totals depend on location rather than area size. For example, northern Maharashtra receives heavy rainfall followed by long dry periods, while areas closer to the equator get less annual rainfall but have longer rainy seasons.

Biodiversity

The Western Ghats region is a biodiversity hotspot. It is home to nearly 30% of all plant and animal species found in India, most of which are found only in this region. At least 325 species of animals and plants worldwide are at risk of extinction and live in the Western Ghats.

The Western Ghats include four types of forests and ecosystems in the Indomalayan region, which covers parts of Asia. The northern part of the region is generally drier than the southern part. These ecosystems include dry forests in areas with less rain, shrub forests near the foothills, wetlands like peat bogs and swamps, and grasslands at high altitudes in the southern Western Ghats. These grasslands are mixed with sholas, a special type of forest found in valleys between mountains.

Earlier studies found about 4,000 to 5,000 types of plants with stems and roots, of which about one-third were found only in the region. Later research identified 7,402 species of flowering plants in the Western Ghats. Of these, 5,588 are native to the region, 376 are non-native plants that have spread naturally, and 1,438 are plants that people have planted. Of the native plants, 2,253 are found only in India, and 1,273 of those are found only in the Western Ghats. About 645 types of trees live in the region, with 56% of them found only in the Western Ghats. There are 850 to 1,000 types of mosses, liverworts, ferns, and lichens, with many of these species found only in the region.

The Western Ghats are home to thousands of animal species, including at least 325 species that are at risk of extinction. A 2010 report listed the number of animal species in the region, in addition to more than 6,000 types of insects.

The Western Ghats have one of the largest tiger populations in the world, with about 985 tigers counted in 2022. The region also has the largest wild Indian elephant population, with about 11,000 elephants across eight groups. Other animals include endangered species like the lion-tailed macaque, Nilgiri tahr, leopard, and gaur. The Nilgiri tahr, once nearly extinct, had about 3,122 individuals in 2015. Other smaller animals found only in the region include the Malabar large-spotted civet, Nilgiri marten, and stripe-necked mongoose.

At least 19 types of birds are found only in the Western Ghats, including endangered species like the rufous-breasted laughingthrush and the vulnerable Nilgiri wood-pigeon. Other birds include the near threatened grey-breasted laughingthrush and the least concerned Malabar parakeet.

A 2014 report identified at least 227 types of reptiles in the region. The snake family Uropeltidae is found only in the Western Ghats. Many reptile species and genera are unique to the area, including a large population of mugger crocodiles. The region also has many types of frogs, toads, and other amphibians, many of which are found only in the Western Ghats. New frog species continue to be discovered in the 21st century.

The southern part of the Western Ghats has more types of fish than other areas. Thirteen fish genera are found only in the region, including Betadevario and Travancoria. The most common fish families include Cyprinids (72 species), hillstream loaches (34 species), and catfishes (19 species). The region is also home to fish like the Denison barb and the Malabar mahseer. In 2011, 97 fish species were considered at risk of extinction, including 12 critically endangered and 54 endangered species.

The Western Ghats have at least 258 types of land snails, many of which are found only in the region. A total of 77 freshwater snails and clams have been recorded, though the actual number is likely higher. Some of these species are at risk of extinction, including the mussel Pseudomulleria dalyi and the snail Cremnoconchus.

There are about 6,000 types of insects in the Western Ghats. Of the 334 butterfly species found in the region, 316 live in the Nilgiri Biosphere Reserve. The region is home to 174 species of dragonflies and damselflies, 69 of which are found only in the Western Ghats. These insects are often found near rivers and streams.

Historically, the Western Ghats were covered in dense forests that supported wildlife and the native tribal people. The region’s difficult terrain made it hard for people from the plains to settle or farm. During British rule, large areas of forest were cleared for agriculture and logging. This led to the destruction of habitats and the loss of many species. The main threats to wildlife include habitat loss, overuse of resources, illegal grazing, mining, poaching, and the introduction of non-native species.

To protect the region, the Indian government has created many protected areas, including two biosphere reserves, 13 national parks, wildlife sanctuaries, and reserve forests. The Nilgiri Biosphere Reserve covers 5,500 square kilometers and is the largest protected area in the Western Ghats.