Emerald tree monitor
Encyclopedia
The Emerald Tree monitor (Varanus prasinus), or the Green Tree monitor, is a small-to-medium-sized arboreal monitor lizard
. It is known for its unusual coloration, which consists of shades from green to turquoise
, topped with dark, transverse dorsal banding. This coloration helps camouflage
it in its arboreal habitat. It also makes the Emerald Tree monitor highly coveted by private collectors and zoos alike.
in 1831; however, Gray's original holotype
(RMNH 4812 in the National Natural History Museum
in Leiden) was lost and the species was redescribed by Schlegel eight years later as V. prasinus using the found specimen. The generic
name Varanus is derived from the Arabic word waral (ورل), which translates to English as "monitor". Its specific
name, prasinus, is Latin
for the color green
.
V. prasinus is a member of the Euprepiosaurus subgenus. It is closely related to several other arboreal
species and when combined these are often referred to as the V. prasinus species group
. In addition to V. prasinus itself, this species group, whose members are all allopatric, includes V. beccarii (Aru Islands
), V. boehmei (Waigeo Island), V. bogerti (D'Entrecasteaux Archipelago), V. keithhornei (Cape York Peninsula
), V. kordensis
(Biak Island), V. macraei
(Batanta Island
), V. reisingeri (Misool Island) and V. telenesetes (Rossel Island).
about 40 million years ago and migrated to Australia
and the Indonesian archipelago around 15 million years ago.
, as well as several adjacent islands, and the northern Torres Strait Islands
. The green tree monitor is reported to thrive in lowland environments including tropical evergreen forests, palm swamps and cocoa plantations.
The emerald tree monitor is about 75–100 cm (29.5–39.4 in) long with a slender body that helps it support itself on narrow branches. It also has a prehensile tail and long claws that it uses to grip branches. Unlike other varanids this monitor defends its tail rather than lashing with it for defense when threatened. The soles of the feet of the emerald tree monitor have enlarged scales which aid the lizard when climbing.
s such as katydids, stick insects, cockroach
es, beetle
s, centipede
s, spider
s, crab
s, bird
s, and small mammal
s. Before swallowing stick insects, the lizards tear off the legs. Captive
specimens tear off the limbs of rodents prior to eating them and as a result they are capable of swallowing mammals of a considerable size: A 135 grams (4.8 oz) lizard was documented as eating a 40 grams (1.4 oz) rodent, an animal almost one-third its size. Paleontologist and Biology Professor at Temple University
, Michael Balsai has observed V. prasinus eating fruit(bananas) in captivity as has herpetologist and author, Robert G. Sprackland.
, each weighing 10.5–11.5 g (0.370376602103676–0.405650564208788 oz) and measuring about 2 by 4.5 cm (0.78740157480315 by 1.8 in). As many as three clutch
es are laid throughout the year; captive clutches have been laid in January, March, April, November, and December. The female emerald tree monitor lays her eggs in arboreal termite
nests. The eggs hatch between 160–190 days, typically from June to November after which the young eat the termites and the termite's eggs within minutes of hatching. Sexual maturity is reached in about two years.
Monitor lizard
Monitor lizards are usually large reptiles, although some can be as small as in length. They have long necks, powerful tails and claws, and well-developed limbs. Most species are terrestrial, but arboreal and semiaquatic monitors are also known...
. It is known for its unusual coloration, which consists of shades from green to turquoise
Turquoise
Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl648·4. It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue...
, topped with dark, transverse dorsal banding. This coloration helps camouflage
Camouflage
Camouflage is a method of concealment that allows an otherwise visible animal, military vehicle, or other object to remain unnoticed, by blending with its environment. Examples include a leopard's spotted coat, the battledress of a modern soldier and a leaf-mimic butterfly...
it in its arboreal habitat. It also makes the Emerald Tree monitor highly coveted by private collectors and zoos alike.
Taxonomy
Varanus prasinus was first described as Monitor viridis by John Edward GrayJohn Edward Gray
John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray ....
in 1831; however, Gray's original holotype
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
(RMNH 4812 in the National Natural History Museum
Naturalis
Naturalis is the national natural history museum of the Netherlands, based in Leiden. It originated from the merger of the Rijksmuseum van Natuurlijke Historie and the Rijksmuseum van Geologie en Mineralogie in 1984. In 1986 it was decided that the museum had to become a public museum and a new...
in Leiden) was lost and the species was redescribed by Schlegel eight years later as V. prasinus using the found specimen. The generic
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name Varanus is derived from the Arabic word waral (ورل), which translates to English as "monitor". Its specific
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...
name, prasinus, is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for the color green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
.
V. prasinus is a member of the Euprepiosaurus subgenus. It is closely related to several other arboreal
Arboreal locomotion
Arboreal locomotion is the locomotion of animals in trees. In every habitat in which trees are present, animals have evolved to move in them. Some animals may only scale trees occasionally, while others are exclusively arboreal. These habitats pose numerous mechanical challenges to animals...
species and when combined these are often referred to as the V. prasinus species group
Species group
A species group is an informal taxonomic rank into which an assemblage of closely related species within a genus are grouped because of their morphological similarities and their identity as a biological unit with a single monophyletic origin.-Use:...
. In addition to V. prasinus itself, this species group, whose members are all allopatric, includes V. beccarii (Aru Islands
Aru Islands
The Aru Islands are a group of about ninety-five low-lying islands in the Maluku province of eastern Indonesia. They also form a regency of Indonesia.-Geography:...
), V. boehmei (Waigeo Island), V. bogerti (D'Entrecasteaux Archipelago), V. keithhornei (Cape York Peninsula
Cape York Peninsula
Cape York Peninsula is a large remote peninsula located in Far North Queensland at the tip of the state of Queensland, Australia, the largest unspoilt wilderness in northern Australia and one of the last remaining wilderness areas on Earth...
), V. kordensis
Varanus kordensis
The Biak tree monitor is a member of the Varanidae family found on Biak Island in Indonesia. It is also known as the kordo tree monitor. Long considered a subspecies of the emerald tree monitor , most authorities now treat it as a separate species.-Description:The Biak tree monitor is mainly...
(Biak Island), V. macraei
Varanus macraei
The Blue Spotted Tree Monitor, Varanus macraei, is a species of Monitor lizard found on the island of Batanta in Indonesia. It is named after Duncan MacRae, founder of the reptile park “Rimba” on Bali. -Description:...
(Batanta Island
Batanta
Batanta is one of the four major islands in the Raja Ampat Islands in Papua province, Indonesia. Its area is 453 km² and its highest point is 1184 m.- Fauna :The following mammals are found on the island:...
), V. reisingeri (Misool Island) and V. telenesetes (Rossel Island).
Evolutionary development
The evolutionary development of V. prasinus started with the Varanus genus, which originated in AsiaAsia
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...
about 40 million years ago and migrated to 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...
and the Indonesian archipelago around 15 million years ago.
Distribution
Emerald tree monitors and their close relatives can be found in New GuineaNew Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
, as well as several adjacent islands, and the northern Torres Strait Islands
Torres Strait Islands
The Torres Strait Islands are a group of at least 274 small islands which lie in Torres Strait, the waterway separating far northern continental Australia's Cape York Peninsula and the island of New Guinea but Torres Strait Island known and Recognize as Nyumaria.The islands are mostly part of...
. The green tree monitor is reported to thrive in lowland environments including tropical evergreen forests, palm swamps and cocoa plantations.
Description
Ecology
When threatened, the emerald tree monitor will flee through vegetation or bite if cornered. It is one of the few social monitors, living in small groups made up of a dominant male, several females, and a few other males and juveniles.Diet
The emerald tree monitor's diet consists of large tree dwelling insectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s such as katydids, stick insects, cockroach
Cockroach
Cockroaches are insects of the order Blattaria or Blattodea, of which about 30 species out of 4,500 total are associated with human habitations...
es, beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s, centipede
Centipede
Centipedes are arthropods belonging to the class Chilopoda of the subphylum Myriapoda. They are elongated metameric animals with one pair of legs per body segment. Despite the name, centipedes can have a varying number of legs from under 20 to over 300. Centipedes have an odd number of pairs of...
s, spider
Spider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s, crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s, and small mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s. Before swallowing stick insects, the lizards tear off the legs. Captive
Captivity (animal)
Animals that live under human care are in captivity. Captivity can be used as a generalizing term to describe the keeping of either domesticated animals or wild animals. This may include for example farms, private homes and zoos...
specimens tear off the limbs of rodents prior to eating them and as a result they are capable of swallowing mammals of a considerable size: A 135 grams (4.8 oz) lizard was documented as eating a 40 grams (1.4 oz) rodent, an animal almost one-third its size. Paleontologist and Biology Professor at Temple University
Temple University
Temple University is a comprehensive public research university in Philadelphia, Pennsylvania, United States. Originally founded in 1884 by Dr. Russell Conwell, Temple University is among the nation's largest providers of professional education and prepares the largest body of professional...
, Michael Balsai has observed V. prasinus eating fruit(bananas) in captivity as has herpetologist and author, Robert G. Sprackland.
Reproduction
Clutches consist of up to five eggsEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, each weighing 10.5–11.5 g (0.370376602103676–0.405650564208788 oz) and measuring about 2 by 4.5 cm (0.78740157480315 by 1.8 in). As many as three clutch
Clutch
A clutch is a mechanical device which provides for the transmission of power from one component to another...
es are laid throughout the year; captive clutches have been laid in January, March, April, November, and December. The female emerald tree monitor lays her eggs in arboreal termite
Termite
Termites are a group of eusocial insects that, until recently, were classified at the taxonomic rank of order Isoptera , but are now accepted as the epifamily Termitoidae, of the cockroach order Blattodea...
nests. The eggs hatch between 160–190 days, typically from June to November after which the young eat the termites and the termite's eggs within minutes of hatching. Sexual maturity is reached in about two years.