By Kevin Winner
Geographic Range
There are two subspecies of Amazon tree boa. Corallus hortulanus hortulanus occurs in the Guianas, Amazonia, and south-eastern Brazil (to the Tropic of Capricorn). Corallus hortulanus cooki is found in southern Central America, northern Columbia, northern Venezuela, Trinidad and Tobago, and the southern Windward Islands (St. Vincent and the Grenada Bank). (Henderson, 1997)
Biogeographic Regions:
neotropical 
(native ).
Habitat
(2952 ft)
Amazon tree boas are found in a wide variety of habitats. They are common in arboreal regions with high humidity, especially Amazon rainforest. They can also be found in dry areas such as savannas or dry forests (Huang 2006).
Most Corallus hortulanus specimens studied are found 1 to 2 m or more above the ground in trees or other vegetation. They have also been observed active on the ground. Amazon tree boas are also relatively common along rivers (Martins & Oliveira 1999). (Huang, 2006; Martins and Oliveira, 1999)
These animals are found in the following types of habitat:
tropical ; terrestrial .
Terrestrial Biomes:
forest ; rainforest ; scrub forest .
Other:
riparian .
Physical Description
(20.67 to 74.02 in; avg. 53.15 in)
Corallus hortulanus is well known for its highly variable color and patterns. They have small, claw-like remnants of vestigial hindlimbs in the cloacal region. Their base color varies from pale tan to black, with yellowish and reddish tinges. They are marked by a series of blotches or bands that are often broader in the middorsal area. The head has five dark stripes that extend from the eyes. The venter color is also variable, from cream to reddish brown, and either with or without darker markings. The eyes can be yellowish, grayish, or reddish, and they have a reflective membrane that results in eyeshine at night. The tongue is black. Males and females are similar in size and markings. They range from 525 to 1880 mm in length, usually from 1200 to 1500 mm (Martins & Oliveira 1999). (Martins and Oliveira, 1999)
Some key physical features:
ectothermic ; heterothermic ; bilateral symmetry .
Sexual dimorphism: sexes alike.
Reproduction
Amazon Tree Boas breed once yearly.
Copulation occurs between March and May.
There is little information on wild mating. In an attempt to at least provide some relevant information, captive breeding techniques from one thorough description are summarized below:
Beginning in early November, evening temperatures drop from the stable summer temperatures of 77 to 78 degrees F to a nightly low of about 70 to 72 degrees F by the first week of December. This change is as gradual as possible in captivity. At the same time, a daytime high of 83 to 85 degrees F is introduced. These temperature gradients are important in triggering mating behaviors. After approximately 2 months of exposure to these new temperatures, most males will begin to display courtship behavior. Frequently males will shed shortly before beginning courtship. The courtship behavior consists of "tail-writhing" around the enclosure. After this has begun, the male and female are introduced and the male's courtship behavior will induce ovulation in the female. Females are also more receptive to mates if they are introduced shortly after a shed. Around March to April, the pair will have begun actively copulating. The snakes will copulate multiple times during this period. In captivity it is possible to have one female mate with multiple males, though this is not recommended as the males will often become highly aggressive and fight each other. In some cases, high levels of male aggression have been noted resulting in a dangerous situation for the female. (Mendez, 2000)
In Amazon tree boas, ovulation occurs in the female several weeks after copulation. During gestation period, females seek areas in direct sunlight or other warm areas to bask. Amazon tree boas give birth to live young. The gestation period is 6 to 8 months. Newborns will shed their skin 8 to 14 days after birth. After about 3 years, Amazon tree boas will reach sexual maturity. (Mendez, 2000)
Key reproductive features:
iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; induced ovulation ; ovoviviparous .
After the young are born they are immediately independent of their mother. Male Amazon tree boas do not contribute to the care of their young. (Mendez, 2000)
Parental investment:
no parental involvement; pre-fertilization (provisioning, protecting: female); pre-hatching/birth (provisioning: female).
Lifespan/Longevity
Wild records of longevity are not available in the literature. Average lifespans for Amazon tree boas in captivity are approximately 20 years.
Behavior
Corallus hortulanus is a notoriously aggressive species. When approached, it bites and makes an s-coil. When manipulated, it may form into a ball, constrict and rotate the body (Martins & Oliveira 1999). They are solitary and may be active at night and during the day.
Communication and Perception
Most members of the family Boidae possess infrared sensitive receptors in labial pit organs. Amazon tree boas have particularly large infrared pits, which allow them to sense heat well. An extensive study by Ebert et. al. (2006) examined the structure of these IR pits. They also have good eyesight that they use to hunt during the day. As are most snakes, Amazon tree boas are sensitive to vibrations and have good chemoreception, which is often used in communicating reproductive information.
Communicates with:
chemical .
Perception channels:
visual ; infrared/heat ; acoustic ; vibrations ; chemical .
Food Habits
Amazon tree boas have been reported to eat: birds (including Chloroceryle inda, Coereba, Elaenia), bats (probably Phyllostomus bicolor, Myotis), frogs (Elachistocleis), rodents (Akodon, Mus, Rattus), lizards (Anolis, Basiliscus, Iguana), and marsupials (Marmosa). These observations suggest that Corallus hortulanus has a broad diet of mainly vertebrate prey. (Martins and Oliveira, 1999)
Amazon tree boas hunt at night using their infrared sensitivity or during the day using vision. They are typically ambush hunters, sitting on a branch with the front part of their body hanging in an S-shaped curve from the branch. They can strike at prey that are a surprising distance from themselves. Prey are often pushed off the tree branch as they are struck, in which cases the snake will gather the body in several of its coils. (Huang, 2006; Martins and Oliveira, 1999)
Primary Diet:
carnivore (eats terrestrial vertebrates).
Animal Foods:
birds; mammals; amphibians; reptiles.
Predation
It has been proposed that the color patterns of Amazon tree boas helps to camouflage them from predators during the day (Martins & Oliveira 1999). (Martins and Oliveira, 1999)
Anti-predator adaptations::
cryptic .
Ecosystem Roles
Corallus hortulanus are important predators of vertebrates in their native ecosystems.
Economic Importance for Humans: Negative
Amazon tree boas are aggressive and will attack humans without warning, though only adults pose any serious danger to humans as this species is non-venomous. (Martins and Oliveira, 1999)
Ways that these animals might be a problem for humans:
injures humans (bites or stings).
Economic Importance for Humans: Positive
Amazon tree boas are popular pets for snake hobbyists and are a fairly common export in the pet trade. About 3,000 of these snakes were exported live from Guiana in 2002, and 1,902 were exported from Suriname in the same year (CITES 2002).
Corallus hortulanus cookii (also sometimes known as Corallus cookii) was once commonly traded. However, this type of tree boa is native to only one island (St. Vincent), which has stopped exporting herpetofauna for commercial purposes (Mendez 2001) ("Export quotas for specimens of species included in the CITES appendices for 2002", 2002; Mendez, 2001)
Ways that people benefit from these animals:
pet trade .
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
Amazon tree boa populations are not considered to be at risk.
For More Information
Find Corallus hortulanus information at
Contributors
Tanya Dewey (editor), Animal Diversity Web, University of Michigan Museum of Zoology.
Kevin Winner (author), University of Maryland, Baltimore County. Kevin Omland (editor, instructor), University of Maryland, Baltimore County.
