The Caatinga is a xeric shrubland and thorn forest, which consists primarily of small, thorny trees that shed their leaves seasonally.

The Caatinga is the only exclusively Brazilian biome, which means that a large part of its biological heritage cannot be found anywhere else on the planet.

The Caatinga covers the interior portion of northeastern Brazil bordering the Atlantic seaboard (save for a fringe of Atlantic Forest), extending across nine states: Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia, and parts of Minas Gerais.

[5] Although the climate is typically hot and semi-arid, the Caatinga includes several enclaves of humid tropical forest,[6] with trees 30–35 m (98–115 ft) tall.

Succulent and crassulaceous species dominate; non-succulents exhibit small, firm leaves and intense branching at the base, akin to shrubs.

Most authors divide the Caatinga into two different subtypes: dry ("sertão") and humid ("agreste"), but categorizations vary to as many as eight different vegetative regimes.

[Note 2] Endemic mammal species include: The oldest human remains in the Caatinga are found in the Serra da Capivara National Park, in Piauí, where artifacts, rock paintings, and a skull named "Zuzu" were discovered, dating back approximately 8,000 years.

Thus, these three major groups developed a series of rituals, customs, traditions, languages, and religions based on their interaction with the Caatinga's nature and other cultural heritages.

However, the first contacts with colonizers in the 16th century decimated numerous indigenous nations and tribes through diseases, enslavement, and invasion of territories for cattle ranching, sugar mills, and new settlements.

In the interior, the largest groups are the Xukurus and Pankarus, from the Pernambuco Caatinga, totaling 12,000 and 7,000 indigenous peoples, possibly of Macro-Jê origin.

Over 1000 years ago, native peoples may have unintentionally created the environment of the modern-day Caatinga through constant slash-and-burn agriculture, thereby stymying plant succession and preventing major rainforests from growing within the region.

[10] One of the most productive species, Melipona subnitida, known locally as jandaíra, produces up to 6 liters of honey a year, resulting in economic profit for the population.

[12][13] Overgrazing and timbering for fuelwood have decimated local vegetative populations; outside irrigated regions, the area has begun to desertify à la Sahara and Sahel.