Partial skeletons of the giant, boa-constrictor-like snake named “Titanoboa” found in Colombia hint that there may be no cap on temperatures in the tropics as global warming kicks in (Illustration: Jason Bourque/U of Florida)

THE newly unearthed remains of the world’s largest snake could settle a debate over whether global warming will bump up temperatures in the tropics.

Some researchers say tropical temperatures will rise in line with the rest of the world. Others say the “thermostat” theory means there is a limit to how hot they can get.

Jason Head at the University of Toronto, Canada, and colleagues dug up the 60-million-year-old relative of the boa constrictor in a Colombian coal mine (Nature, DOI: 10.1038/nature07671). Temperature can affect body size, and for the snake to grow to 13 metres long and weigh over 1 tonne, the tropics would have to have been at about 33 °C, 7 °C warmer than today’s average.

This “refutes the idea of the thermostat”, says Head, and tells us “what equatorial temperatures will be as we continue to warm the planet: very hot.”