This can be a physically demanding and potentially dangerous procedure for the snake, because its metabolism is accelerated up to sevenfold and it becomes vulnerable to attack by another predator.
Instead, a study of boa constrictors showed that constriction halts blood flow and prevents oxygen from reaching vital organs such as the heart and brain, leading to unconsciousness within seconds and cardiac arrest shortly thereafter.
[7][8][9] In conjunction with observations of oral and nasal hemorrhaging in prey, constriction pressures are also thought to interfere with neural processing by forcing blood towards the brain.
Internal organs with high metabolic rates, including the brain, liver, and heart, begin to stop functioning and die due to ischemia, a loss of oxygen and glucose.
There is evidence that boa constrictors have more difficulty killing ectotherms—animals like lizards and snakes that rely on external heat to regulate their body temperatures.