A new study found how boa constrictors actually kill their preys and it is not through suffocation. The experts wanted to know how these snakes, even with the lack of legs, can successfully end the lives of their preys through immobilization and constriction. Although these techniques are well recognized, the actual mechanism of pressure that these animals induce to eventually destroy their prey is not well established.
The researchers conducted the study by first anesthetizing rats before, during and after they are subjected for constriction by the boas. The scientists then monitored the cardiovascular statuses of the rats during the entire experiment to determine the changes in circulatory functions. The researchers obtained objective data such as blood pressure and heart rate of the rats.
The findings of the study, published in the Journal of Experimental Biology, show that the grip of the snakes severely restricted the blood flow of the subjects to the point that oxygen supply to the organs are cut off. Specifically, the researchers discovered that the peripheral arterial blood pressure (PBP) at the femoral artery decline to half of the initial rate and the central venous pressure (CVP) shoot up by six times from the baseline value within 6 seconds of constriction. As per electrocardiographic readings, the heart rate decreased to about half of the baseline data during a 60-second period of constriction. In the end, 91 percent of the rats were found to exhibit impairments in electrical cardiac functioning.
Blood samples were also immediately drawn from the study subjects after the experiment. The results revealed that the serum potassium levels of the rats doubled from its baseline value and the blood pH decreased from 7.4 to 7.0.
Impeding the blood flow going to the brain will induce rodents to pass out within seconds, says Professor Scott Boback, lead author of the study from Dickinson College in Pennsylvania. The halt of circulation demonstrated in the experiment is said to be a more efficient, faster and an absolute method of killing preys.
The researchers of the study think that monitoring during constriction may provide a valuable insight into the mechanisms that transpire during crush injuries, which usually lead to complicated organ damage in humans. The study is the first to identify and measure physiological parameters that provide proof that constriction by snakes may subject preys faster than expected through circulatory arrest.
Photo: James Emery | Flickr
