Cat gap

The Cat Gap is a term used in paleontology to describe a period in the early Cenozoic era, specifically within the Paleogene period, where there is a noticeable lack of fossil evidence for felid (cat-like) species in North America. This period spans approximately from 33.9 to 20.6 million years ago, during the late Eocene to early Miocene epochs. The Cat Gap is significant for understanding the evolutionary history and biogeographical distribution of modern cats and their ancestors.

Overview

During the Cat Gap, North America appears to have been devoid of the felid predators that had previously existed in the region. This absence is intriguing to scientists because it coincides with a time of significant environmental change and faunal turnover. The reasons behind the Cat Gap are not entirely understood, but several hypotheses have been proposed, including climate change, competition with other predators, and barriers to migration that may have prevented felids from entering North America from other continents.

Before the Cat Gap

Prior to the Cat Gap, during the late Eocene, evidence suggests that early forms of cat-like animals, along with a variety of other mammalian predators, inhabited North America. These early carnivores were not true felids but shared common ancestors with modern cats. The diversity of these early carnivorous mammals set the stage for the evolution of true cats.

After the Cat Gap

The end of the Cat Gap is marked by the appearance of the first true felids in North America. These cats migrated from Asia across the Bering land bridge, which connected Siberia to Alaska. This migration led to the diversification of felids in North America and eventually to the wide variety of cat species found across the continent today, including both big cats such as the lion, tiger, and leopard, and smaller species like the bobcat and lynx.

Hypotheses for the Cat Gap

Several theories have been proposed to explain the Cat Gap:

• Climate Change: Significant climatic shifts during the Paleogene may have created conditions unsuitable for felids and other predators, leading to their local extinction in North America.
• Competition: Increased competition from other predators, such as canids (dog-like animals), which were diversifying at the time, may have outcompeted felids for resources.
• Geographical Barriers: Changes in geography, such as the rise of mountain ranges or changes in sea levels, may have created barriers that prevented the migration of felids into North America from other continents.

Impact on Evolutionary Studies

The Cat Gap is of particular interest to paleontologists and evolutionary biologists because it offers insights into the patterns of extinction and radiation (the diversification of species) among carnivorous mammals. Studying this period helps scientists understand how animals adapt to changing environments and how those changes can influence biodiversity over millions of years.

See Also

• Paleontology
• Cenozoic
• Felidae
• Evolution of mammals