Urutu Snake

Urutu snakes are aggressive pit vipers capable of causing severe tissue damage and even death to humans with their venomous bites.

Urutu snakes, also called yarará grande, wutu, and crossed pit vipers, are native to rainforests and humid regions of Brazil, Argentina, Paraguay, and Uruguay. They are highly venomous pit vipers in the Bothrops genus, also called lanceheads.

Being pit vipers, these snakes have heat-sensing pit organs on both sides of their head, between their eyes and nostrils. These organs help them sense opossums, small rodents, amphibians, and other warm-blooded prey in their wetland habitats. When attacking, the aggressive snakes pierce the animal’s flesh with their large fangs and inject a tissue-damaging venom.

Although the Urutu’s venom is potentially deadly, only about 2% of bitten humans die from the bite. Most bitten people experience tissue death in the area of the bite, as well as extensive bleeding. Many bite victims must undergo amputations of limbs after these attacks.

It is because the Urutu has such dangerous bites that they are often hunted or trapped by farmers in their native geographies. Most of this hunting and trapping is to prevent permanent injury, severe symptoms of the bite, or death to livestock or humans.

5 Amazing Facts

1. Larger females: The female Urutu snake grows longer and heavier than males of the same species
2. Humid living conditions: Urutus do not live in dry conditions and instead make their home in wetlands, tropical forests, marshes, swamps, and alongside major rivers or streams
3. Member of the Viperidae family: The Urutu shares a family with more than 200 species of venomous fanged snakes, including rattlesnakes
4. Triangle-shaped head: Being a pit viper, the Urutu has a telltale triangular head due to the placement of its venom glands
5. Damaging venom: The Urutu’s venom causes immediate tissue damage in the body, also inhibiting blood clotting and sometimes leading to death

Evolution and Origins

Urutu snakes, known for their potent venom and aggressive nature, are not typically inclined to view humans as prey but display defensive behavior when they feel threatened, which is more common when encountered by farmers as they primarily inhabit the wild regions of South America.

Snakes are believed to have evolved from land-dwelling lizards during the Middle Jurassic Epoch (approximately 174.1 million to 163.5 million years ago), and the oldest known snake fossil, Eophis underwoodi, dates back around 167 million years and was discovered in southern England.

As predators, snakes have a diverse diet encompassing rodents, insects, birds’ eggs, and young birds while relying on their cold-blooded nature to adjust their body temperature by seeking suitable external environments for thermoregulation.

Where to Find Them

The Urutu snake is found in countries of South America, specifically Brazil, Paraguay, Uruguay, and Argentina. Its habitats include tropical forests, semitropical forests, and temperate deciduous forests within marshes, swamps, riverbanks, floodplains, and other areas with high humidity.

The snakes are often found on sugarcane plantations of South America, as well as in open fields, rocky regions, grasslands, tropical savannas, and on the banks of rivers and streams. Urutu is not found on dry lands or in arid regions.

Although these snakes can be deadly because of their venomous bite and aggressive nature, some people choose to keep them as pets. They are sometimes available on the exotic pet market. States and local regions each have their own laws about owning these animals.

Despite being legally able to own one in some areas, having a pet Urutu brings risks. One woman from Ohio was killed by her pet Urutu pit viper in 2004. When the bites are not deadly, they cause severe symptoms and even permanent physical injuries.

Scientific Name

The Urutu snake of South America has dozens of other names that vary according to geographic region and dialect. The most common names are Urutu, wutu, and crossed pit viper. In Argentina, it is called yarará grande and víbora de la Cruz.

Brazilians call the snake boicoatiara, coatiara, cruzeira, jararaca de agosto, jararaca rabo-de-porco and urutu, as well as other variations of these terms. Paraguans call the Urutu by several names, including yarará acácusú, mbói-kwatiara and mbói-cuatiá. Uruguans refer to the venomous pit viper as yarará, víbora de la cruz and crucera.

The snake’s scientific name is Bothrops alternatus. This official name of Bothrops comes from the Greek term bothros, meaning “pit”, and ops, meaning “eye” or “face,” in reference to the pit viper’s heat-sensitive facial organs. That term is coupled with the Latin alternatus, meaning “alternating” and referring to the snake’s color pattern. The snake is in the pit viper family Viperidae and class Reptilia.

Population and Conservation Status

According to the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species as of 2014, the Urutu snake’s conservation status is of “least concern.” This means the snake’s population is stable, widespread, and under no major threats. The animal’s most common threat is from sugarcane farmers hunting and trapping the snakes that encroach on their lands or pose a risk to livestock or humans.

Because they are not widely hunted and have little commercial value outside of the exotic pet trade, the snakes are able to thrive within their native habitats. Of course, global warming and habitat destruction pose risks to the snake populations in the future.

Reproduction

These snakes give birth to from 3 to 12 live young. Baby snakes that are born life instead of hatching from eggs are called neonates. Urutu neonates are capable of making a venomous strike as soon as they are born.

Appearance and Description

Urutu snake colors vary widely. They can range from dark chocolate and almost black blotched pattern colors to tan, olive green, and gray. The most common description of the snake’s coloration is that of a yellow, tan, or off-white body with a dark brown kidney-shaped pattern from neck to tail. The head is mostly dark brown in color with tan to white markings creating a well-defined pattern.

Urutu’s body length is usually between 31 inches and 47 inches. But there are documented reports of the snakes measuring as long as 67 inches in the wild. Females are much longer and heavier than males.

Other ways to identify an Urutu snake include the animal’s head. Like all venomous pit vipers, the snake’s head is triangular in shape. This shape relates to the placement of the venom glands on each side of the head, making the head extend dramatically outward from the neck.

The snakes also have two long fangs that inject venom into their prey, although these are not readily visible unless the snake is biting. They locate their prey using visible heat-sensitive organs on each side of the face, between each eye and the snout.

How to identify Urutu snakes:

• Typically 31 inches to 47 inches long, but can measure as long as 67 inches
• Yellow, tan, or off-white body and belly color
• Dark brown, black, tan, gray, or olive green dorsal pattern from head to tail tip
• Blotchy pattern kidney shapes defined by yellow, tan, or off-white borders
• Triangular head indicating the placement of venom glands on each side of the head at the neck
• Heat-sensing pits on each side of the head between each eye and the snout

Venom: How Dangerous Are They?

Urutu snakes are usually deadly to humans in only 2 of every 100 bites. Their venom generally causes a range of extreme symptoms like major tissue damage at the region of the bite which can lead to gangrene and even the need for limb amputation. All injured victims experience pain and swelling, with most also experiencing delayed blood clotting by 12 minutes or longer.

Effects of a venomous Urutu snake bite include:

• Severe tissue damage
• Delayed blood clotting by 12 minutes or longer
• Local pain and swelling
• Bleeding from the gums
• Local blistering
• Tissue death
• Severe scarring
• Death in about 2% of cases

A deadly dose of Urutu snake venom is typically between 2.2mg of venom per kilogram of body weight to 4.1mg of venom per kilogram of body weight. Treatment for the snake’s bite requires the use of specific antivenin. If you are bitten by an Urutu snake, one of the most important facts about this animal is that it is critical that you seek immediate emergency medical attention.

Behavior and Humans

Urutu snakes are highly venomous and defensive. They do not seek out humans as prey but do aggressively defend themselves when they perceive a threat. Because the snakes live in most wild regions of South America, farmers are usually the only humans crossing paths with these pit vipers.

Farmers are also responsible for many of the snakes’ deaths each year through hunting and trapping to ensure the safety of people and livestock near the reptiles’ habitat. When humans keep Urutu snakes as exotic pets, there is greater potential for human injury and death from the highly venomous bite.

Similar Animals

• Golden Lancehead
• Fer-de-Lance
• Bushmaster