Climate change theories put forward to explain the extinctions at the close of the Pleistocene are unsatisfactory because the animals in question survived changes of similar magnitude. The overkill theory is unsatisfactory because predators cannot hunt their prey to extinction without starving themselves. Combining the theories, without a proposed mechanism, is incomplete and inadequate.

All current models assume animal populations decrease monotonically to extinction. An alternate scenario and computer simulation characterized by a boom/bust population pattern is presented. It suggests: H. sapiens reduced predator populations, causing a herbivore population boom, leading to overgrazing of trees as well as grass, resulting in environmental exhaustion and extinction of herbivores.

If true, increased continentality of the Holocene may be accounted for thus: herbivore population explosion forces animals to eat all available food, browsers and mixed feeders denude the mixed grassland/woodland of trees, the changed vegetation pattern reduces atmospheric moisture from transpiration resulting in increased continentality.

An interactive system dynamics computer simulation will be available for demonstration and testing.

Back to the Holmes and Watson conversation

To the earlier exploration - "The Pleistocene Holocene Transition - The Case of the Arboricidal Megaherbivores"