Viper Boa

Candoia aspera

Last updated: August 2, 2022
Verified by: AZ Animals Staff

These boas aren't really vipers, they're nonvenomous constrictors that look like vipers.


Viper Boa Scientific Classification

Scientific Name
Candoia aspera

Read our Complete Guide to Classification of Animals.

Viper Boa Conservation Status

Viper Boa Locations

Viper Boa Locations

Viper Boa Facts

Bandicoots, lizards, frogs, other small animals.
Main Prey
Name Of Young
Group Behavior
  • Solitary
Fun Fact
These boas aren't really vipers, they're nonvenomous constrictors that look like vipers.
Biggest Threat
People who kill it out of fear and mistaken identity.
Most Distinctive Feature
Squared head and blunt nose, giving it a viper-like look.
Distinctive Feature
Rough, keeled scales like vipers' scales
Other Name(s)
New Guinea ground boa, Papuan ground boa, Papuan viper boa, New Guinea viper boa
Gestation Period
7 months
Litter Size
  • Nocturnal
Favorite Food
Common Name
Lazy snake
New Guinea and some Indonesian Islands

Viper Boa Physical Characteristics

  • Brown
  • Grey
  • Yellow
  • Fawn
  • Red
  • Black
Skin Type
Up to 20 years
Up to 3 feet
Age of Sexual Maturity
2-4 years

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Dubbed the “lazy snake” by locals, the viper boa is slow-moving, even by boa standards.

These nonvenomous constrictors are nocturnal and native to New Guinea and several of the surrounding islands. Their small stature and beautiful colors make them loved by keepers, even though they’re rare in captivity, and it’s hard to find captive-bred individuals.

Incredible Viper Boa Facts

  • These boas have a reputation for bad attitudes and biting.
  • They stay small and max out around three feet long.
  • In their native environment, they are sometimes confused with the smooth-scaled death adder.
  • Like other boas, viper boas give birth to their young. These small snakes can give birth to up to 20 babies in one litter.

Viper Boa Scientific Name and Classification

Historically, the viper boa was a member of the Boidae family, subfamily Candoiinae; its scientific name is Candoia aspera. Including the viper boa, there are five members of the genus. Its siblings include the Fiji boa, Indonesian tree boa, Solomon Island ground boa, and the Palau bevel-nosed boa.

Keeled scales are a trait of the Candoia genus snakes. Owing to its rough, keeled scales, the specific name of aspera is Latin and means rough.

In 2014, Pyron, Reynolds, and Burbrink proposed moving the Candoia genus snakes to a new family – Candoiidae. They based it on genetic research that showed these snakes being more closely related to the sand boas in the genus Eryx than the other boids. Most sources still refer to this genus as Boidae; however, the subfamily of Candoiinae is used by most.

Viper boas have a few common names. Among those are the New Guinea viper boa, Papuan ground boa, and New Guinea ground boa. The locals sometimes call these snakes “the lazy snake” because it’s relatively lethargic, even when compared to other boas.

Types of Viper Boa

Surprisingly, for a snake that’s as little studied as the viper boa, scientists have recognized two subspecies: Candoia a. aspera, and Candoia a. schmidti. There isn’t a lot of information on what is different between the two.

Viper Boa Appearance

This snake is small, and adults reach 2-3 feet long. The viper boa is sexually dimorphic; the females of the species are noticeably larger than the males, which have fairly long, pointed spurs on either side of the cloaca. Its color and patterns vary widely naturally, much like the Amazon tree boa. This snake can range from reds and yellows to brown or almost black, with black-outlined saddle markings that extend down the length of its body. Its markings are highly varied; sometimes they merge a bit and look more reticulated or net-like, and other times, they appear more like bars. The saddle markings don’t extend to its belly, which is usually cream or tan in color.

The viper boa is short and stocky, especially for boas, with a head designed for digging. From its snout to its eyes, a slight scoop is visible. This snake has a typical triangle-shaped boa head, but its blunted angular snout and strongly keeled scales give it a viper-like appearance, giving rise to its common name.

Red phase viper boa

This short and stocky snake is often mistaken for the smooth-scaled death adder.


Viper Boa Behavior

This species has a reputation for a bad attitude. It’s noting, however, that this is likely due to the fact that most individuals in captivity were wild-caught. Often, snakes in the wild carry parasites; the stress of being taken from the wild and plopped into an enclosure can make any animal grumpy. In contrast, captive-bred viper boas don’t typically carry parasites, making them healthier. When they’re handled regularly, they can become wonderful pets for an experienced keeper.

Some Candoia snakes may sometimes be found in the trees, but that’s not the case with this fossorial snake. They live on the ground and do not climb trees. During the day, these ground-dwelling nocturnal snakes burrow into the leaf litter or find an appropriate hideout away from the sun. That slight scoop in their head shape allows them to shovel dirt and leaf litter out of the way so they can burrow more easily.

Like other boas, viper boas have strong bodies and constrict their prey before swallowing it whole. They aren’t quite as active as other boas, though, so they do not need to hunt as frequently. They’re a great example of an ambush predator that lies in wait until prey wanders too close.

Viper Boa Habitat and Diet

Viper boas are native to New Guinea, the Bismarck Archipelago, and the Admiralty Islands. Their natural habitat is warm and humid, and these snakes love the water. They’re often found swimming in the swamps of their home range. They also inhabit forests and plantations with dense vegetation. Seasonal flooding occurs in many of these areas, which suits these almost-water-boas just fine.

In the wild, their diet consists mainly of common spiny bandicoots, lizards, and frogs. Bandicoots are similar in basic appearance to rats and mice, except they’re marsupials and have a much longer snout than rats or mice. Viper boas also eat other small animals like frogs and lizards whenever they are available.

Viper Boa Predators, Threats, Conservation, and Population

According to the 2014 IUCN assessment, the viper boa isn’t under any significant threat and is present in several protected areas. Its large distribution throughout New Guinea gives the species a solid foundation, and at the moment, it isn’t widely harvested for the pet trade.

One threat is its resemblance to the smooth-scaled death adder. Researchers say that their resemblance to the venomous reptile is the reason that some of them are killed on sight.

Researchers don’t know much about this species in the wild. As a result, information on their natural predators is scant. Hopefully, more research on the species will be done so we can learn more about this beautiful snake. However, there are a number of predators on the islands, either natural or introduced, that may feed on these and other snakes. These include birds of prey like the Papuan eagle, dogs, and cats.

Viper Boa Reproduction, Babies, and Lifespan

These snakes reach sexual maturity at 2-4 years of age. At 3-4 years, females are usually ready to breed, having grown large enough to support the babies while they develop. During mating season, they leave a trail of pheromones that several males follow to find them. While males of other boa species engage in ritual combat, the males of this species don’t appear to do so.

After about seven months of gestation, viper boa females give live birth to 12-20 babies that are called neonates or snakelets. The babies are ready to take care of themselves right after they’re born and often look like miniatures of their parents.

Most viper boas can live for 10-20 years. In the wild, their lifespan is probably closer to 10-15 years, but in captivity, they can live to be 20.

Next Up

  • Rosy boas are native to California, Arizona, Nevada, and Mexico. They’re shy and reclusive, with gorgeous colors!
  • If you thought that all snakes were solo hunters, think again. The Cuban boa is probably the only snake that scientists know to hunt cooperatively.
  • Snakes come in all sizes, shapes, and colors. The Amazon tree boa exhibits a wide range of colors in nature.

View all 25 animals that start with V

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About the Author

Gail Baker Nelson is a writer at A-Z Animals where she focuses on reptiles and dogs. Gail has been writing for over a decade and uses her experience training her dogs and keeping toads, lizards, and snakes in her work. A resident of Texas, Gail loves working with her three dogs and caring for her cat, and pet ball python.

Viper Boa FAQs (Frequently Asked Questions) 

Are viper boas venomous?

No. These are nonvenomous members of the Boidae family, making boa constrictors their cousins. They’re called viper boas because they exhibit a form of mimicry, and are often mistaken for the smooth-scaled death adder.

Where do viper boas live?

These snakes live on New Guinea, Manus, Bougainville, and the Solomon Islands.

Are viper boas aggressive?

Yes, they can be, but most of the time, this applies to the wild-caught snakes. While they prefer escape over biting, they’re not going to hesitate to bite if they feel threatened.

What do viper boas eat?

Mostly, they seem to prefer a small bandicoot, but they also eat lizards, frogs, and other small animals.

How do viper boas hunt?

These “lazy snakes,” as the locals call them, are the epitomy of the ambush-predator. They’re slow-moving, and stay hidden until something wanders close enough to catch.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.


  1. Tallowin, O., Allison, A., Parker, F. & O'Shea, M. 2018. Candoia aspera. The IUCN Red List of Threatened Species 2018: e.T196559A2459665. Accessed on 31 July 2022., Available here:
  2. Forcart, Lothar. “Nomenclature Remarks on Some Generic Names of the Snake Family Boidae.” Herpetologica, vol. 7, no. 4, 1951, pp. 197–99. JSTOR, Accessed 1 Aug. 2022., Available here:
  3. Viper boa | Encyclopedia of Life, Available here:
  4. Candoia aspera |, Available here:
  5. New Guinea Ground Boa | Ecology Asia, Available here:

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