The scientific study of caves is known as:

Speleology is the scientific study of caves and other natural underground voids. It involves exploring, mapping, and understanding caves, including their formation, structure, geology, hydrology, and biology. Speleologists, or cave scientists, investigate how caves are formed, the processes that shape them, and the unique ecosystems within these subterranean environments.

Caves are typically formed through geological processes such as the dissolution of limestone by water, volcanic activity, or erosion. Speleology studies these processes to understand landscape evolution and geological history. Additionally, speleologists examine the mineral formations, such as stalactites and stalagmites, and analyze cave sediments to reconstruct past climates and environmental conditions.

Caves also harbor specialized organisms, such as bats, insects, and microorganisms, adapted to low-light and nutrient-limited environments. Speleology combines aspects of geology, hydrology, biology, and environmental science, making it an interdisciplinary field with both scientific and practical importance.

Other options are unrelated:

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  Haematology is the study of blood.

  
  


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  Oology is the study of eggs, especially bird eggs.

  
  


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  Oneriology is the study of dreams.

  
  

Studying caves is important for scientific research, environmental conservation, and understanding natural hazards, such as groundwater contamination or sinkhole formation. Speleology also supports tourism, education, and archaeology by helping explore and preserve unique underground sites.

In summary, the scientific study of caves is called speleology, focusing on cave formation, structure, ecology, and geological processes, making it a vital branch of everyday science and Earth studies.