SNAKE BEHAVIOR: MOVEMENT, FEEDING, BREEDING

SNAKE MOVEMENT

How snakes move, from dailyinfographic.com

The skeleton of a snake is essentially a skull connected to a long spinal columns and rib cage. Most of the muscles run longitudinally between the vertebrae and the ribs. Some are short connecting one rib to another. Other are longer, spanning as many as 40 vertebrae. When muscles are contracted they move close together, causing a section of snake to curve.

Snakes move forward by making their skin crawl. Most snakes have horny, backward-pointing plates on the undersides of their bodies that overlap and grip the ground. Muscular movements within the body move the snake forward.

Snakes move by producing alternating waves of muscles contractions. Describing this movement, David Attenborough wrote: "They flex their flank muscles in alternate bands so that their body is drawn into a series of S-shaped curves. As the contractions ravel in waves down their body, their flanks are pressed against obstacles on the ground such as stones or plant stems and the snake is able to push itself forward. In short it wriggles. If it is put on a surface completely free of any irregularities...the technique fails and the snake simply writhes helplessly."

When hunting, it is very important for snakes to move quietly and with a minimum of movement so as not to alert its prey. Under these circumstances, the snake approaches the prey straight on, keeping its is head still, body straight and slowly moving forward by using contracting muscles on its belly.

A striking snake arches its body near its head to for form an "S" and then straightens out its body. A completely snake can not strike. A striking snake an generally only strike out half a body length

Many snakes are good climbers, using the scales on their undersides to grip on to on bark, or winding themselves around branches. In the rain forest you are more likely to find snake sin the trees than on the ground. Many snakes are also good swimmers They can inflate their lung to float on the top of the water an use their belly scales to grip the surface of the water and slide across the water almost as easily as they do on land.

Snake Breeding

baby King cobra

Male snakes have two sex organs (called hemipenises) hidden behind a flap at the base of their tails. Some species use them alternatively in quick, successive couplings or gang-bang orgies. Others favor one hemipenis in long copulation that deters rivals.

The Brahminy blind snake is a snake species with no males. Females lay their eggs without having them fertilized by a mate. The snakes habit of hiding away in potted plants has enabled to spread all over the world.

Female snakes sometimes store sperm inside their bodies for several months until a climate change signals the snake it is the right time to start fertilization. Pregnant females are sometimes unable to feed during the later part of their pregnancy and go months without feeding, relying on fat stored in their bodies.

Most snakes lay eggs but some give birth to live young that hatched from eggs inside the female snake's body. Snake eggs usually have a soft, flexible, non-brittle shell. The young are born encased in a membrane that breaks. Some species lay their eggs among rotting leaves or logs to keep them warm. The eggs can take several days to several months to hatch. The determining factor as to when they hatch is hot the weather is.

Depending in the species, snakes lay between 2 and 100 eggs with most species laying between seven and nine. Young snakes have a special scale at the end of their end of their nose call the egg tooth which they use to break out of their leathery shells.

Snake Hunting and Feeding Behavior

All snakes are carnivorous and they prefer live prey. They often rely on stealth to capture prey and swallow it whole. Small species eat insects, worms, slugs, scorpions and frog's eggs. Medium size ones eat mice, baby birds, eggs, frogs, fish and other small animals. Large snakes can eat small mammals, other snakes, birds, and even babies. Some species can consume prey that is two and half times their body weight.

Snakes rarely eat more than once a week, unless their prey is really small. On average a snake takes 12 to 14 days to digest a meal, and it is not unusual for a snake to go several months without eating After a big meal some snakes remain inactive for several days while it digests its prey. If a snake is threatened it sometimes regurgitates its meal so it can escape more quickly.

cobra

Many snakes like to laze around and hang out in places their prey is most likely to pass, stalk their prey when it gets near and get close enough to strike. Many snakes have camouflage markings and an ability to stay very still so they are not detected. Many can catch their prey with a single strike. Some species specialize in going into the holes of burrowing animals. Many climbing snakes seek out nests and feed on eggs and chicks. A few species use their tails as lure prey which mistake the tail for a worm or caterpillar

Snakes that feed on large, potentially-dangerous creatures kill them first, usually by poisoning or through constriction. Large prey is swallowed head first. Otherwise the legs might get caught up in the snake’s throat. The insides of the snake clamp down on the prey, preventing it from moving or opening its mouth to damage the inside of the snake.

Everything but hair and feathers is digested. Some snakes that primarily eat eggs swallow the eggs whole and a sharp objects in their gullets break the shell, which is when spit out. Many snakes can go months or years without drinking, instead getting the water they need from their food. Those that do drink stick their heads under water and use their jaws to pump water into their body or suck water from wet leaves.

Snake Feeding Anatomy

Snakes are unable to dismember their prey and must swallow it whole. They have a lower jaw bone that is divided in half and hinged with ligament that stretches sideways. The bones supporting the lower jaw on the skull are movable so the mouth can open very wide. These things allow snakes to swallow food that is larger than themselves.

Snakes are able to breath and not choke when they swallow large prey because their windpipe extends almost to the end of their mouth and they have special muscles that pull the windpipe opening forward past the prey as it is being swallowed.

python skull

The fangs and teeth of most snakes point backwards which helps force large prey towards the throat and keep even slippery creatures such as frogs from slipping back out. Snakes move prey into their gullet by alternately moving the right and left sides of their jaws, Depending on the size of the prey the process can take from a few seconds to a few hours but generally takes a few minutes.

Rippling muscles inside the snake move the prey towards the stomach. Sometimes the prey remains alive while it moves through the snake’s throat. The prey of poisonous snakes often dissolved from the inside out inside the snake.

In order to swallow many snakes crawl over their food by contracting their muscles, pushing their bodies on the ground and their prey inside their bodies at the same time. Some snakes rotate their jaw forward, then pull it backwards, and "walk" their head over the victims. Snail eating snakes rotate their jaws in such a way that they hook the snake and pull it from the shell.

Snake That Can Swallow Several Times Its Weight

A relatively small snake — not pythons which can swallow prey as large as themselves — holds the record for swallowing the largest prey whole relative to body size. Jennifer Nalewicki wrote in Live Science: Known as the Gans' egg-eater (Dasypeltis gansi), this skinny, nonvenomous African snake has a gape so big that it can swallow spherical bird eggs whole despite its diminutive size, which tops out at about 40 inches (102 centimeters) in length. Its ability to dine on prey much larger than itself comes from the stretchy skin that connects the snake's left and right lower jawbones, allowing it to open its maw exceedingly wide, according to a study published August 8, 2023 in the Journal of Zoology. [Source:Jennifer Nalewicki, Live Science, September 8, 2023]

Gans' egg-eater can devour prey three to four times larger than snakes that are classified as "generalists," such as the black rat snake. It can swallow eggs whole despite its small size, after which it contorts its body to crack the egg and spits out the empty shell. "They seem to be the world record holder for the size of their gape and their overall size," study author Bruce Jayne, a biologist and professor in the Department of Biological Sciences at the University of Cincinnati, told Live Science. "Their ability is even more extreme than Burmese pythons'."

Jayne put the Gans' egg-eater's egg-swallowing skills to the test — even capturing its eating abilities on video — to investigate whether it had the largest gape relative to its size. In the lab, Jayne fed a Gans' egg-eater a quail egg. After swallowing it whole, the snake contorted its spine to crack the egg, eventually regurgitating only the broken eggshell. (The entire process lasted 15 to 30 minutes.) The fact that teeth are "nearly absent in the species" proves beneficial, since it "helps the liquid contents of the egg not to be expelled" as the snake swallows it, Jayne said.

Constricting Snakes

Snakes like boa constrictors and pythons seize their prey with their mouths, and wrap their coils around it so the prey can no longer expand its chest and breath. It was often thought that these snakes kill through suffocation, crushing or choking. But often something more than mere suffocation is also going on. A suffocated rat, for example, usually dies in four minutes. A rat killed by a constricting snake dies in one minute. Studies indicate that snakes disrupt the circulation of their victims, doubling their victims’ blood pressure so that heart can not pump sufficient blood to the brain, lungs and other tissues, killing with a heart attack or stroke.

Constriction is the term used to describe the suffocation methods of suffocating snakes. Although some species of venomous and mildly venomous snakes use constriction to subdue their prey, snakes that employ the technique venom. In many cases the suffocating snake strikes at its prey and holds on, pulling the prey into its coils. In the case of very large prey, the attacking snake pulls itself onto the prey and wraps one or two loops around the prey, forming a constriction coil. The snake monitors the prey's heartbeat to ascertain it is dead. [Source: Wikipedia]

Contrary to myth, suffocating snake do not generally crush their prey, or break their bones. However, wild anacondas have been observed to cause broken bones in large prey. Also contrary to common belief, the snake does not suffocate the victim. 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 In addition, many species of snakes have been shown to constrict with pressures higher than those needed to induce cardiac arrest.

Based in part on observations of oral and nasal hemorrhaging in prey, constriction pressures are also thought to interfere with neural processing by forcing blood towards the brain. This means that constriction can work by different mechanisms at varying pressures. It likely interferes with breathing at low pressures, can interrupt blood flow and overwhelm the prey's usual blood pressure and circulation at moderate pressures, and can interfere with neural processing and damage tissues at high pressures. During constriction when the prey's heart is impeded, arterial pressure drops while venous pressure increases, and blood vessels begin to close. The heart is not strong enough to pump against the pressure and blood flow stops. 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.

Strikers and Lungers

Using high-speed video, Cornell herpetologist Bill Ryerson filmed snakes attacking dead rodents and found species fit into two broad categories: strikers and lungers — with the difference based on the kinds of teeth they possess. Sascha Pare, wrote in Live Science: Strikers attack at lightning speed from above, impaling their prey with needlelike teeth at the front of their lower jaw before wrapping their head over and around to inject venom with their fangs, or to squeeze the animal to death. These snakes include many boas, such as boa constrictors (Boa constrictor), and pythons.[Source: Sascha Pare, Live Science, January 17, 2024]

Kingsnakes, pine snakes (Pituophis melanoleucus) and some ground boas are lungers, according to Ryerson, who is a senior lecturer in anatomy at Cornell University's College of Veterinary Medicine. Lungers "strike more slowly and don't open their mouths as wide," Ryerson, who presented his research at the annual meeting of the Society for Integrative and Comparative Biology in January 2024, told Live Science. "They make contact with both jaws simultaneously."

Herpetologists have long focused their attention on snakes' fangs, which are teeth modified to inject venom, but they have largely ignored the rest of the teeth. "We just assumed they are all the same and will not tell us much about the evolution of snakes," Ryerson said. But Ryerson's work suggests otherwise. While a snake's other teeth may not catch our eyes quite the same as its fangs do, they are still important in how snakes evolved to attack and kill, he said.

"I've done quite a bit of work in the last few years on the striking behavior of snakes and I began to wonder how those teeth function in the ultrafast striking, especially for the non-venomous snakes like our boas and pythons," Ryerson said. While peering into the mouths of dozens of preserved specimens, Ryerson found that some snakes, such as boa constrictors, have narrow, upright teeth in their front lower jaw, while others, including kingsnakes, have stouter, curved teeth.

Then, Ryerson used X-rays to scan the jaws and teeth of almost 70 snakes from 13 species, Science reported. Using high-speed video, he also filmed snakes charging at dead rodents that he wiggled in front of them to analyze the snakes' striking behavior. His observations neatly sorted into two categories, Ryerson said. Strikers showed more variation in the size and shape of their teeth, which became shorter, broader and more curved toward the throat. Lungers, on the other hand, had broad, curved teeth all along their upper and lower jaws.

The fact that snakes have different dentitions wasn't so surprising, as it was "unlikely that all the teeth would be the same across all species," Ryerson said. "However, I was surprised by how well the shape of the teeth corresponded to the strike behavior."More specialized snake species, such as those that live in trees or underground, may not fit into either category, Ryerson said.

Image Sources: Wikimedia Commons

Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, CNN, BBC, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.

Last updated February 2025