An incredible video shows an African rock python (Python sebae), one of the largest snake species on the planet, slowly swallowing an impala whole. The video, recorded in MalaMala Game Reserve in South Africa, shows the snake's head slowly slinking across the impala's body as the snake seems to magically stretch barely wide enough to swallow the creature whole.

Amazingly, taking down such a large animal is not out of the ordinary for these predators, experts told Live Science. These snakes can reach an impressive 20 feet (6 meters) long, and they may prey upon creatures even longer.

"Pythons are ambush hunters," said Matthew Johnston, an associate professor of avian, exotic and zoological medicine at Colorado State University. "They will take down whatever happens to walk in front of them when they are hungry."

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Typically, Johnston told Live Science, rock pythons hang out in rocky outcroppings and caves, tasting the air with a special sense organ in their mouths called Jacobson's organ. Rock pythons' forked tongues allow them not only to use Jacobson's organ to taste scents from nearby animals but also to detect subtle changes in air temperature that occur when a warm-blooded animal such as an impala (Aepyceros melampus) wanders close by.

When the snake strikes, its mouth opens a full 180 degrees, allowing it to punch its prey with a mouthful of teeth. Once the teeth have sunk into the skin, the snake rapidly coils its body around the animal.

After the strike comes one of the most brutal aspects of the rock python's hunting tactics: The strike doesn't actually kill its target. Instead, the python wraps its muscular body around its victim, cinching its vise-like grip tighter every time the animal takes a breath, until it passes out. Once it's time to eat, the python swallows its catch whole, no matter how big it is.

This always seems to involve swallowing the animal head first.

"I've seen constrictor species search for upwards of an hour to find the head of a prey animal," Tom Weaver, assistant curator of ectotherms at Denver Zoo, told Live Science. This may give the snake the best shot at consuming prey quickly, because the angle of feathers or fur might create the least amount of resistance if the snake is swallowing its prey from the head down.

Both ingesting and digesting large prey pose unique challenges to the rock python.

Before it starts the painfully slow process of swallowing its prey whole, the python has to wrap its whole mouth around the catch. Contrary to popular lore, the snake does not actually unhinge its jaws, both experts said. Instead, its jaws are held together by a series of ligaments that behave like thin, stretchy rubber bands. That means the snake doesn't have to dislocate each side of its jaw from the other, because the jaw bones are barely attached to each other to begin with. This adaptation allows the left and right halves of the jaw to "walk" along the body of large prey, Johnston said. The snake uses one side of its rear-facing teeth to grip food while twisting its head to move the other side along the body.

It's not the strike or the constriction that kills prey; it's stomach acid, Johnston said. The inside of a snake's stomach is almost pure hydrochloric acid.

"We have stomachs with a pH of 4 or 5, but pythons have a pH of 1," he said.

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The strong acid not only kills the prey by dissolving it but also protects the snake. After eating a large meal, the python is in a digestive race against putrefaction. It has to completely digest its meal before it starts rotting. If prey does rot before digestion, toxic gases can build up in the digestive tract, likely killing the snake.

Once the snake has swallowed its meal, it typically finds a place to hide and digest. If the meal was impala-size, it might be months before the snake is hungry again.

However, immediately after eating such a massive meal, the African rock python will have some trouble moving. After a large meal, a python will have a food bulge that might make slithering sluggish. Large meals, like an impala, might create a food bulge that lasts a few weeks before fully breaking down. During this time, it will be vulnerable to attack, in which case it will regurgitate the entire kill in order to escape.

Although it may look like an easy kill for a fearsome predator, living on a diet of large prey is anything but easy.

Originally published on Live Science.