14 February 2009 [BR for Everyone]
Biotic regulation and a Big Snake

From 4th to 10th February 2009 world mass-media had been tirelessly informing people of Earth that world's largest prehistoric snake was found in Colombia. The snake was named Titanoboa cerrejonensis (supposedly it was a boa constrictor-like species). But it was the accompanying news that appeared even more intriguing: based on the snake size, scientists estimated prehistoric tropical climate to be several degrees Celsius warmer than it is today. Climate change is a hot topic!


We note that these estimates are based on the theoretical approach developed within the framework of the biotic regulation theory. The corresponding papers were published in 2005 in Oikos and Proceedings of the Royal Society of London Series B Biological Sciences — see references 5 and 4, respectively, in the now well-known publication of Head et al.

The essence of the phenomenon consists in the proposed existence of a universal metabolic minimum (the minimal amount of energy consumed by the organism per unit time per unit body mass), beyond which the organisms cannot enjoy a successful biological or ecological performance. Metabolic power per unit mass decreases with growing body size (large animals are generally "slower" than the related smaller species), yet in cold-blooded animals it increases with growing ambient temperature. Therefore, the higher the temperature, the larger body size species of a given evolutionary group can ultimately afford without risking to fall below the dangerous minimum threshold. Consequently, the gigantic snake should have lived at a higher ambient temperature than the smaller extant snakes. Comparing its size with the size of the largest extant snakes it is possible to estimate how hot it was when the Titanoboa was thriving in the tropics. This is what Head et al. did having put into our metabolic formulae the size of their snake.