STL Science Center

STL Science Center

30 December 2015

Extinction Hypotheses

Happy Madagascan children with an Aepyornis egg, (C) Madagascar-tribune
There are many hypotheses as to how Aepyornis went extinct. Many of those hypotheses center on human interaction because post-settlement by what we would now consider the indigenous people (those are the Malagasy people, a healthy melting pot of groups from places like Borneo and southeastern Africa). Considering that Madagascar was the last large landmass on the planet to be settled by humans, the wildlife had a very good long run of evolving with little to no human disturbance; evidence exists for foraging groups spending short periods of time on the island prior to permanent settlement. The question with Aepyornis becomes what kind of human interaction could have caused a 400 kg bird to go extinct? Hunting seems to be a natural answer to that question, but the bird was so enormous that a sustained "farming" of the bird would have been able to feed the population of the entire island quite well for an extended period without causing the extinction of the birds. This may have been the neither goal of the population nor within their scope of worry. However, consider the implications of a "farmable" 400 kg bird and how that might change holiday dinners! Another possibility was the hunting of the young or unborn birds. Due to their size it is unlikely that Aepyornis ever laid large clutches of eggs; extant ratites are capable of laying a small amount of eggs in each breeding season but are considerably smaller. As each egg was large enough to feed multiple people it is feasible to assume that they were taken entire nests at a time, allowing for either multiple meals or a village sized egg feast. Assuming communal nesting sites, the breeding season for these birds alone could have sustained the island and more. This path to extinction is straightforward of course; the ingestion of one's offspring eventually leads to the downfall of one's population and subsequent eradication of the species over time. The third hypothesis is concerned with a combination of the other two hypotheses coupled with habitat loss as a major factor in the extinction of the birds.

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