Even when ribs which are normally used for breathing are constricting, posterior ribs can use the non-breathing section of the lungs to suck air in and allow the snakes' survival.ДЄs these muscles are found in all snakes, it suggests that they could have been a crucial development in the evolution of these animals, and perhaps possessed by the ancestors of the group.ДЄmong the squamate reptiles, the levator costae are only found in limbless reptiles, suggesting it may be an adaptation that is crucial to a long, legless body form. The scientists found that the different sections of the ribs could move independently, with the muscles only activated in areas required to keep the snake breathing. This included defensive hissing, which saw some of the largest rib movements across the length of the body.ДЄn expandable cuff used to measure blood pressure was then wrapped around the snakes to allow the researchers to see how the snakes responded when the animals couldn't move certain areas of their body, as if they were constricting prey.Д®lectrical measuring was also conducted to see if levator costae muscles for different sections of the ribs could activate independently, or if all the ribs were moved at once.

The researchers used x-rays to examine how the ribs of captive Boa constrictor moved in different areas of the body during different behaviours. How does Boa constrictor breathe while squeezing and swallowing? Breathing is particularly important during these activities, which can increase the amount of oxygen the animal needs by up to 17 times its normal level.ДЄs Boa constrictor's lungs are also being compressed when it is squeezing prey to death, the survival of the snake has remained something of a mystery. However, when the ribs are being used for compression or expanding to swallow, the snakes can't also move them to keep the snake breathing. Instead, they move their ribs in and out to achieve the required changes in pressure to breathe. They also lack a diaphragm, which is usually used to draw air into the body. Their body can also expand to accommodate large food as snake ribs are only attached to the spine. As a result, their jaw can expand to allow them to swallow significantly larger prey than may otherwise be expected. Unlike mammals, the jaw bones of snakes are unfused and are instead connected by elastic tissue. Once their prey is dead, Boa constrictor consumes it whole.

But more recent research has shown that instead the snakes cut off the blood supply to organs including the heart and brain, causing rapid unconsciousness and death. It was originally thought that the snakes killed their prey by cutting off its air supply and suffocating the animals. As theВ snakes get larger they can tackle bigger prey, with wild pigs among the largest eaten by Boa constrictor. To catch their food the snakes wrap their body around the prey and squeeze. The snakes eat a range of animals, from fish and small birds to monkeys and other reptiles. Some scientists now suggest there could beВ as many as five separate species, such as Boa imperator, although this is still debated.

The most well-known species is Boa constrictor,В which was for a long time the only species of its genus. The boas are a genus of snake found in Central and South America.

Constrictor