Global warming threatens crocodile populations with extermination

Wednesday, November 29, 2006 by: Jerome Douglas
Tags: global warming, species extinction, health news

https://www.naturalnews.com/021195_global_warming_species_extinction.html

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Alison Leslie, a noted crocodile expert, recently said that the rise in global temperatures may cause a larger female population among the world's crocodiles. This means the possibility of eventual extinction of these aquatic reptiles.

Leslie is looking at crocodile populations from the River Nile in Okavango, Botswana and is preparing a study on crocodiles that will be featured in the documentary, "A Year on Earth," which will premier on the Discovery Kids channel on Dec. 3.

Crocodiles are one of the oldest species on our planet and thrive in freshwater bodies like lakes and rivers -- and sometimes even in backwaters. The gender of a crocodile is not determined through genetic means like many other species on earth; rather, the gender of crocodiles is affected by the nest temperature during incubation.

According to Leslie, the rising temperatures on earth could lead to more female crocodile births while male crocodile births would be reduced -- eventually leading to a global population of female crocodiles which would kick-start the decline of the species. An all-male brood typically results from nest temperatures in the range of 89.6 to 91.4 degrees Fahrenheit.

Leslie indicated that when the incubation temperature rises or dips below this range, the result is female crocodiles -- an overabundance of them. In addition, the genders in a single crocodile brood vary according to where the eggs are placed in the nest.

With these variables in play -- and with temperatures varying at different levels in the nest, even small differences -- these changes in incubation temperatures results in markedly different sex ratios according to Leslie. More female hatchlings because of climate change “could lead to eventual extirpation of the species from an area," added Leslie.

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