Top 11 Most Fascinating Facts About Rattlesnakes

Rattlesnakes, also known as rattlers or buzzworms, originate from the Americas, belonging to the subfamily Crotalinae. They are venomous snakes with extremely potent venom.

Rattlesnakes, also referred to as rattlers or buzzworms, are a group of venomous snakes belonging to the genera Crotalus and Sistrurus in the subfamily Crotalinae. They are characterized by their rattling tails used for hunting and warning of danger. There are 32 rattlesnake species with 65-70 subspecies. They are all native to the Americas, ranging from southern Canada to central Argentina. Some common species include the Mojave rattlesnake, Rattlesnake, etc.

Their species diversity makes them highly intriguing to human curiosity.

The skeletal structure of rattlesnakes comprises only the skull, ribs, spinal column, and rib bones, although rattlesnakes belonging to the Henophidia branch still retain vestiges of the pelvic girdle and hind limbs. The skull of rattlesnakes consists of a solid and perfect skull box, with many other bones loosely attached to it, specifically the highly flexible jawbones, facilitating the capture and ingestion of large prey.

The left and right sides of the lower jaw are connected by a flexible ligament to the front tips, allowing them to spread apart, while the posterior tips of the lower jawbones articulate with the quadrate bone, providing additional flexibility. The bones of the lower jaw and the quadrate bone can also detect vibrations originating from the ground. Because the sides of the jawbone can move independently of each other, when a rattlesnake places its jaws on a surface, it has sensitive collective hearing that helps it detect the prey's location. The quadrate bone is a small bone located behind and above the skull, in the 'throat' region, acting as an attachment point for the muscles of the snake's tongue, similar to that in all other tetrapods.

The spinal column of rattlesnakes consists of approximately 200 to 400 (or more) vertebrae. The vertebrae all have protruding parts that allow for connections to robust muscles, enabling movement without the need for legs. Autotomy, a common characteristic in some lizard species, is not present in rattlesnakes.

The name 'rattlesnake' originates from the characteristic features of their bodies. The tail of this snake species is unique in that it can produce sound.

Rattlesnakes are also found in Vietnam, possessing relatively large bodies, with the largest adults in the world measuring over 2 meters long and weighing from 5 to 7 kilograms. Their skin is brown, with spotted backs featuring various patterns depending on the species and habitat.

All rattlesnakes have hollow tails, consisting of numerous consecutive rings that gradually decrease in size towards the tip, containing no flesh inside. When the tail shakes, the rattling sound is produced by the collision of the hard keratin layers.

Like other typical snake species, rattlesnakes undergo the process of shedding skin approximately 5 to 6 times per year. After each shedding, their tail layer thickens slightly, resulting in a louder rattling sound. They also possess a set of rigid jaws and two sharp fangs in the upper jaw to deliver venom to their prey.

Rattlesnakes prefer to live in desert or dry forest and grassland areas. Most of the time, they reside in dens, but occasionally, you may find them basking in open areas. If encountered by humans, they tend to retreat, only attacking when their lives are threatened.

The skin of rattlesnakes is covered in a layer of keratin scales. Contrary to the common misconception that rattlesnake skin is slimy, possibly due to confusion with worms, in reality, rattlesnake skin is smooth and dry. Rattlesnakes utilize specialized belly scales for movement, gripping onto surfaces. The scales on the body of rattlesnakes can be smooth, keeled, or granular in texture. The eye caps of rattlesnakes are transparent keratin scales, resembling 'glasses', and these scales always remain closed, hence the idiom 'as shifty as a snake's eyes'.

The shedding of scales in rattlesnakes is called molting. In the case of molting in rattlesnakes, the outermost layer of skin is shed. The scales of rattlesnakes are not separate but rather an extension of the epidermis layer - thus they are not shed separately but rather as a complete outer layer in each molting cycle, akin to peeling the inner layer of a sock outside.

The eyes of rattlesnakes are covered with transparent scales rather than movable eyelids. Therefore, the eyes of rattlesnakes are always open, while for sleep, the iris can close or the rattlesnake can retract its head into the coiled body.

The heart of rattlesnakes is enclosed in a sac, called the pericardium, located at the fork of the trachea. However, the heart of rattlesnakes can move around due to the absence of a diaphragm. This adjustment protects the heart from injury when swallowing large prey that slides down the esophagus. The liver is attached to the gallbladder and pancreas, aiding in blood filtration. The spleen is located within the fatty tissue above the heart, responsible for producing immune cells in the blood. The circulatory system of rattlesnakes is also unique in having a renal portal system, where blood from the tail moves through the kidneys before returning to the heart.

The left lung is usually small or absent as the tubular body shape of rattlesnakes necessitates all organs to be long and slender. In rattlesnakes, only the right lung is functional. This right lung consists of two parts: the anterior part with blood vessels leading to it, and the posterior part which does not participate in gas exchange. This 'sac-like lung' is utilized for buoyancy control in rattlesnakes.

Many paired organs, such as the kidneys or reproductive organs, are arranged alternately in the body, with one part ('left' or 'right') of this organ lying immediately in front of the remaining part ('right' or 'left') of that organ itself. Rattlesnakes do not have lymph nodes.

Vision: The vision of rattlesnakes is not uniform, ranging from just enough to distinguish light from dark to relatively sharp vision, but the general trend is that their vision, although not particularly sharp, is sufficient to allow them to track movements. Rattlesnakes focus their gaze on a particular spot by moving the lens forward and backward relative to the retina, whereas in other groups of animals with a nictitating membrane, the lens is extended.

Smell: Rattlesnakes use smell to track their prey. They smell by using their forked tongue to collect particles in the air, then transfer them to the vomeronasal organ or Jacobson's organ in the mouth for examination. The forked tongue helps rattlesnakes simultaneously sense both smell and taste. Rattlesnakes keep their tongues constantly in motion, sampling particles from the air, soil, and water, analyzing the chemicals found, and determining the presence of prey or predators in the surrounding environment.

Vibration Sensitivity: Parts of the rattlesnake's body in direct contact with the ground are highly sensitive to vibrations; thus, rattlesnakes can detect approaching animals by detecting the slightest vibrations in the air or on the ground.

Thermal Sensitivity: Rattlesnakes have heat-sensitive receptors in deep grooves between the nostril and eye, allowing them to 'see' the heat radiation of warm-blooded prey animals.

Molting (or shedding) in rattlesnakes serves a range of functions. Firstly, it replaces the worn-out outer layer of skin; secondly, it helps remove parasites such as ticks or mites. Shedding the skin is believed to aid in the growth process in some animals like insects; however, whether this holds true for snakes remains a subject of debate.

The shedding of skin occurs periodically throughout the life of a rattlesnake. Before shedding, snakes cease feeding and often move to or hide in a secure location. Just before shedding, the outer layer of skin becomes dull and dry, and the eyes appear cloudy or opaque. The inner layer of the old skin liquefies, causing the old skin to separate from the new layer underneath. After a few days, the eyes clear up, and the rattlesnake 'slithers' out of its old skin. The old skin tears near the mouth, and the rattlesnake slithers out, facilitating the shedding process by rubbing against rough surfaces. In many cases, the old skin is shed in one piece, resembling the peeling of a sock from inside out. The new skin, larger and brighter, has formed just beneath.

Adult rattlesnakes molt only 1 to 2 times per year, but young growing rattlesnakes may shed up to 4 times per year. The shed skin retains intact imprints of the scale pattern.

Rattlesnakes hunt both day and night by luring prey with their tail that can produce sound. They often lie in wait for prey or hunt prey inside caves. Prey is quickly killed by venom. If prey is bitten but moves before dying, rattlesnakes can track its scent. Rattlesnakes prey on birds and rodents, thus playing a crucial ecological role in controlling populations of crop-damaging rodents and stabilizing the ecosystem.

Their diet includes small animals such as lizards, birds, small mammals, fish, insects, snails, other snakes, as well as eggs of these prey species. As rattlesnakes cannot bite or tear food into pieces, they must swallow prey whole. The body size of a rattlesnake significantly influences its feeding behavior. Smaller snakes consume smaller prey.

The jaw structure of rattlesnakes is complex. Contrary to the common belief that snakes can dislocate their jaws, rattlesnakes have very flexible lower jaws, with both halves not rigidly attached, along with a series of other joints in the snake's skull, allowing rattlesnakes to open their mouths wide enough to swallow entire prey, even if the prey's diameter exceeds the width of the snake's body.

After feeding, rattlesnakes enter a resting state while digestion takes place. Digestion is an intense activity, especially after ingesting large prey. In species that feed intermittently, the entire intestine contracts between meals to conserve energy. The digestive system of a rattlesnake then 'bulges' to maximum capacity within 48 hours after consuming prey.

Ranked among the top 10 most venomous snakes in the world, the venom from their fangs can paralyze the nervous system of prey and kill them in just a few minutes, and humans are certainly no exception. A bite from a rattlesnake, if not promptly treated, can cause your heart to stop beating in an extremely short time. A bit of venom entering the wound will travel through the bloodstream, rupturing cells into vessels and leading to internal bleeding.

Most rattlesnakes are highly venomous. Their venom can quickly paralyze the nervous system of prey such as mice, birds, and some other small animals, then stop the victim's heart from beating just a few minutes after being bitten. In the United States, statistics show that about 7,000 to 8,000 people are bitten by rattlesnakes each year, with about 10 deaths.

Most cases of rattlesnake bites occur due to stepping on or getting too close to them. When bitten by a rattlesnake, venom from their fangs will penetrate the wound, into the bloodstream, rupturing cells into vessels and causing dangerous internal bleeding. After being bitten, the wound will swell and be extremely painful. Additionally, the victim will feel anxious, nauseous, and gradually weaken, experiencing heart failure and dying within 6 to 48 hours. If treated with antivenom within the first 2 hours, victims have a chance of rapid recovery. Children bitten by snakes often have more dangerous symptoms than adults.

While snakes employ a variety of reproductive methods, all involve internal fertilization. This is facilitated by a paired organ called the hemipenis, which can evert and retract, located in the male's tail. Hemipenes often have flutes, hooks, or spines to grip the walls of the female's cloaca.

Unlike most snake species, rattlesnakes do not lay eggs but give birth to live young. They mate and reproduce from January to March. After reproduction, female snakes often lose energy and consume fellow snakes to replenish, preparing for the next reproductive cycle.

In addition to the above information, one fascinating aspect that commands respect for this species is that their mating sessions can last up to 22 hours each time.

Having no legs poses no hindrance to the movement of the rattlesnake. They have evolved several different locomotion methods to navigate through various specific environments. Unlike the gaits of legged animals, which form a continuous spectrum, each rattlesnake locomotion is discrete and distinct from the others; transitions between locomotion modes are abrupt.

Sidewinding: Sidewinding is the only method of movement in aquatic environments and is also the most common on land. In this method, the rattlesnake's body alternately flexes from side to side, creating a series of 'waves' moving backward. While this movement may seem rapid, rattlesnakes rarely move faster than 2 body lengths per second, often much slower. This locomotion method has the same net energy expenditure (calories expended per meter moved) as the running gait of lizards of similar mass.

On land: Sidewinding on land is the most common locomotion method for rattlesnakes. In this method, the backward-moving waves push against contact points in the environment, such as rocks, tree branches, or irregularities on the ground. Each object in the environment, in turn, generates a forward and centerward thrust against the rattlesnake, creating a forward push while cancelling out lateral components. The speed of this movement depends on the density of push-off points in the environment.

In water: When swimming, the waves become larger as they move down the length of the snake's body, and the wave propagation speed behind the snake is faster than the snake's forward movement speed. Propulsion is generated by the snake's body pushing against the water. Despite overall similar principles, studies have shown that muscle activation patterns in the aquatic environment are vastly different from sidewinding on land, justifying their designation as distinct locomotion methods.

Straight: The slowest locomotion method of the rattlesnake is straight-line movement, also the only method where rattlesnakes do not need to laterally flex their bodies, although they may still do so when encountering obstacles. In this method, the ventral scales are lifted and pulled forward before the body is lowered and pulled over them. Motion and pause cycles move backward, creating a series of undulating waves along the skin.