Boa constrictors' lethal secret revealed

Scientists in the US have measured how boa constrictors end the lives of their prey. The work has busted a myth that the snakes suffocate their victims. Researchers took measurements - including blood pressure and heart activity - from anaesthetised rats gripped by the snakes. This showed that the lethal grip restricted blood flow severely enough to cut off the blood flow supplying oxygen to its vital organs. The findings are published in the Journal of Experimental Biology. This "circulatory arrest", the scientists say, is a much more efficient, rapid and definite way of finishing off prey than expected. As the lead researcher, Prof Scott Boback, from Dickinson College in Pennsylvania, explained, restricting blood flow to the brain would also make a rodent "pass out within seconds". The researchers believe that recording during a constriction could reveal useful details about how crush injuries cause complex tissue damage in humans. But Prof Boback and his team are interested primarily in the fundamental question of how and why these snakes evolved their unique killing method.READ MORE -http://www.bbc.co.uk/news/science-environment-33625080