Rainfall—or rather, the lack thereof—is a defining feature of deserts. Most deserts receive fewer than ten inches of rain each year, and evaporation outnumbers rainfall. Deserts are often quite hot because more water evaporates from the ground than is restored by precipitation. In addition, those that are hot during the day may become frigid at night due to a lack of cloud and humidity insulation.

Deserts may be devoid of water, but they are not devoid of life. Shrubs and plants have evolved to reduce water loss and efficiently manage the water they do receive. They can cope with harsh circumstances, limited water, and barren terrain. Many desert plants, such as the cactus, can absorb and retain water, allowing them to endure prolonged droughts. Animal diversity is also considerable, notably among reptile species that thrive in hot, dry environments. Animals have evolved to extract water from the food they consume and to save what little water they do have. They usually only come out at night to avoid the hottest part of the day.

The Thar desert is no exception. Drought-resistant trees dot the landscape periodically, especially in the east, while the desert vegetation is largely herbaceous or stunted scrub. In the arid zone, roughly 30 plant species are known for their edible use, and about 20 of these are known for their edible fruits, which can be eaten raw or cooked. Gum arabic acacia and euphorbia can be found on the hills. The khajri (or khejri) tree can be found all throughout the plains.

There are various smaller species, ranging from the very small antelope rat with long hind legs to carnivores such as the grey mongoose, the aggressive ratel or honey badger, desert fox, striped hyena, jungle cat, Indian desert wild cat, and caracal, in addition to the larger antelopes and gazelles.