Common names: emerald tree boa.

Corallus caninus is a non-venomous boa

Boinae

The Boinae are a subfamily of boas found in Central and South America, Africa and Southeast Asia. Five genera comprising 28 species are currently recognized.-Geographic range:...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 found in the rainforest

Rainforest

Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...

s of South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. No subspecies are currently recognized.

Description

Adults grow to about 6 feet (1.8 m) in length. They have highly developed front teeth that are likely proportionately larger than those of any other non-venomous snake.

The color pattern typically consists of an emerald green ground color with a white irregular interrupted zigzag stripe or so-called 'lightning bolts' down the back and a yellow

Yellow

Yellow is the color evoked by light that stimulates both the L and M cone cells of the retina about equally, with no significant stimulation of the S cone cells. Light with a wavelength of 570–590 nm is yellow, as is light with a suitable mixture of red and green...

 belly. The bright coloration and markings are very distinctive among South American snakes. Juveniles vary in color between various shades of light and dark orange or brick-red before ontogenetic coloration sets in and the animals turn emerald green (after 9–12 months of age). This also occurs in Morelia viridis, a species in which hatchlings and juveniles may also be canary yellow or brick-red. As opposed to popular belief, yellow juveniles (as in the green tree python) do not occur in the emerald tree boa.
Based on locality, enough that some herpetologists

Herpetology

Herpetology is the branch of zoology concerned with the study of amphibians and reptiles...

 have considered whether they should be classified as a new subspecies

Subspecies

Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

. The name recently suggested for this morphological variant, but not yet widely accepted, is Corallus batesii [Henderson]. Specimens from the Amazon River

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

 basin tend to grow the largest, are much more docile than their Northern relatives and attain lengths of 7–9 feet (2.1–2.7 m), while the overall average size is closer to 6 feet (1.8 m). Those from the southern end of their range in Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

 tend to be darker in color. Amazon Basin

Amazon Basin

The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...

 specimens generally have an uninterrupted white dorsal line, whereas the white markings in the Northern Shield specimens are quite variable. The snout scales in Amazon Basin specimens are also much smaller than in their Northern, Southern and Western counterparts found, for example, in Surinam, Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

, Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

,and French Guiana

French Guiana

French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

. Hybrid forms between the Northern Shield Corallus caninus and the Amazon Basin form are also known to exist.

C. caninus appears very similar to the green tree python, Morelia viridis, from southeast Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 and Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. Only very distantly related, this is an example of convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

. Physical differences include the head scalation and the location of the heat pits

Thermoception

Thermoception or thermoreception is the sense by which an organism perceives temperature. The details of how temperature receptors work are still being investigated. Ciliopathy is associated with decreased ability to sense heat, thus cilia may aid in the process...

 around the mouth.

Geographic range

Found in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

 in the Amazon Basin

Amazon Basin

The Amazon Basin is the part of South America drained by the Amazon River and its tributaries that drains an area of about , or roughly 40 percent of South America. The basin is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela...

 region of Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, northern Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, and from Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

 to Surinam and the Guianas within the so-called Northern Shield. The type locality given is "Americae." The 'Basin' variant', as the name suggests, is only found along the basin of the Amazon River, in southern Surinam, southern Guiana, southern Venezuela to Colombia, Peru and Brazil and in the surrounding jungles of the Amazon River.

Behavior

A strictly nocturnal and arboreal species. It spends its days in a characteristic coil over a tree branch with its head perched at the center. At night, it will remain coiled on its branch. But extends its head downwards. Curled as if about to strike. It will hold still in this position, waiting for prey to approach directly below. Prey is grasped with the long frontal teeth, pulled in and constricted to asphyxiation.

Feeding

The diet consists primarily of small mammals, but they have been known to eat some smaller bird species as well as lizards and frogs. Due to the extremely slow metabolism

Metabolism

Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

 of this species, it feeds much less often than ground dwelling species and meals may be several months apart.

Previously, it had been thought that the primary diet consisted of birds. However, studies of the stomach contents of this species indicate that the majority of its diet consists of small mammals. Juvenile and neonates have also been known to feed on small lizards and frogs, particularly glass frogs (observation made by Henderson et al.).

It catches the prey with a high speed.

Reproduction

Ovoviviparous

Ovoviviparity

Ovoviviparity, ovovivipary, or ovivipary, is a mode of reproduction in animals in which embryos develop inside eggs that are retained within the mother's body until they are ready to hatch...

, with females producing an average of between 6 and 14 young at a time, sometimes even more. Litters exceeding these numbers are extremely rare. Newly born juveniles have a distinctive brick-red to orange coloration and gradually go through an ontogenetic color change over a period of 12 months, gradually turning to full emerald green.

External links

• Corallus.com: Emerald Tree Boa at Corallus Dot Com. Accessed 4 July 2008.
• Amazon Basins LLC. Accessed 4 July 2008.
• Corallus caninuS. Accessed 8 August 2008.