Zoological Realms


  • Zoo-geographical realms, also known as biogeographic regions, are areas of the world characterized by distinct and unique patterns of flora and fauna.
  • These realms are defined by geographical, climatic, and ecological factors, and they play a crucial role in understanding the distribution of life on Earth.
  • They provide insights into the distribution of species, the influence of geological history, and the impact of environmental factors on the evolution of life forms.

 1. Major Zoo-Geographical Realms:

  • There are several major zoo-geographical realms recognized globally, each with its unique set of ecosystems and species. These include the Nearctic, Neotropical, Palearctic, Ethiopian, Oriental, and Australian realms, among others.


  • Encompasses North America, excluding the high Arctic regions.
  • Diverse ecosystems ranging from arctic tundras to deserts.
  • Iconic species include the American bison and black bears.


  • Covers Europe, Asia (except for the Indian subcontinent), and North Africa.
  • Features diverse landscapes, including the Siberian taiga and Mediterranean scrublands.
  • Home to species such as the Siberian tiger and European brown bear.


  • Encompasses Central and South America, along with the Caribbean.
  • Features the Amazon rainforest, one of the most biodiverse regions on Earth.
  • Iconic species include jaguars, toucans, and howler monkeys.


  • Covers South and Southeast Asia, including the Indian subcontinent.
  • Home to the Bengal tiger, Asian elephant, and diverse bird species.
  • Characterized by tropical rainforests and diverse landscapes.


  • Encompasses sub-Saharan Africa.
  • Rich in diverse ecosystems, including savannas and rainforests.
  • African elephants, lions, and numerous endemic species.
  • Many unique species found only in this realm.


  •  Comprises Australia, New Guinea, and nearby islands.
  • Known for its marsupial fauna, including kangaroos and koalas.
  • Isolated evolution due to geographic isolation is a key feature.

2. Characteristics of Realms:

  • Each realm has distinct climatic conditions, vegetation types, and wildlife species.
  • For example, the Neotropical realm is known for its diverse rainforests, while the Australian realm is characterized by its unique marsupial fauna.

 3. Distribution of Life Forms:

  • The distribution of life forms within these realms is often shaped by geological history and the movement of continents.
  • The concept of "vicariance" plays a significant role, where species are separated due to the splitting of landmasses.

 4. Impact of Continental Drift:

  • The theory of continental drift and plate tectonics has had a profound impact on the formation and separation of zoo-geographical realms.
  • For example, the joining of South America and North America led to the interaction and competition of fauna from these two realms.

 5. Survival of Unique Fauna:

  • Some realms have unique and ancient species due to their isolation from other realms.
  • For instance, Australia's isolation allowed the survival of marsupials, such as kangaroos and koalas, without competition from placental mammals.

 6. Conservation Significance:

  • Understanding zoo-geographical realms is essential for conservation efforts.
  • Conserving species within these realms helps protect unique biodiversity and ecological systems.