In anthropology, the “Altithermal” refers to a warm, dry climatic period during the Middle Holocene (roughly 8200–5000 years BP), which profoundly influenced human subsistence, settlement, and cultural adaptation in regions such as the North American Great Plains, the Great Basin, and parts of Mexico.

🌍 Definition and Chronology

• Altithermal Period: Also known as the Holocene Climatic Optimum, Hypsithermal, or Mid-Holocene Warm Period.
• Timeframe: Approximately 5500–2500 BCE, with regional variation.
• Climate Characteristics:
  • Higher average temperatures.
  • Increased aridity, especially in continental interiors.
  • Shifts in vegetation and water availability.

🔑 Anthropological Contexts

• Great Plains (North America):
  • Foraging peoples adapted to reduced bison populations and water scarcity.
  • Archaeological evidence shows diversification of food sources and new processing technologies.
• Great Basin (Nevada, Utah, California):
  • Pollen records indicate significant vegetation changes.
  • Human groups shifted settlement patterns, often abandoning marginal areas.
• Texas and Mexico:
  • Evidence of population decline and resettlement.
  • Economic shifts from hunting to gathering, then back to hunting after the Altithermal.

📚 Importance in Anthropology

• Subsistence Adaptations: The Altithermal forced communities to innovate—expanding diets, developing storage, and intensifying plant use.
• Settlement Shifts: Populations moved toward reliable water sources, creating new social landscapes.
• Cultural Change: Ritual and symbolic practices often adapted to environmental stress, reflecting resilience.
• Archaeological Insight: Stratigraphy, pollen analysis, and faunal remains provide evidence of how climate shaped human lifeways.

In short: The Altithermal in anthropology is a Middle Holocene warm, dry period that reshaped subsistence, settlement, and cultural practices across North America and beyond, offering a key case study of human adaptation to climate change.

Sources: Southern Methodist University thesis on Altithermal subsistence adaptations; Wikipedia on Holocene Climatic Optimum; JSTOR article on Altithermal cultural evidence in Texas and Mexico; University of Arizona thesis on stratigraphy and past environments; UC Merced study on Altithermal pollen evidence.