In general, varanids are known have well-developed auditory and visual systems. The tongue aids in chemoreception and olfaction, bringing air into the mouth and pressing it up against the large Jacobson's organ, which contains specialized chemoreceptors. This aids them in detecting food sources. Papuan monitors communicate with each other visually (movements such as head weaving during combat), through touch (during courtship behavior), and sound, hissing for short periods throughout a broad frequency span as a warning.
Communication Channels: visual ; tactile ; acoustic
Perception Channels: visual ; tactile ; acoustic ; vibrations ; chemical
This species has not been evaluated by the International Union for Conservation of Nature and Natural Resources. It is listed in Appendix II of CITES, indicating that while they are not yet considered threatened or endangered, trade of these animals must be closely controlled.
US Federal List: no special status
CITES: appendix ii
State of Michigan List: no special status
There is no data regarding mating behavior or development of this species in the wild, but it has been studied in captivity. Egg clutches of 4-12 eggs are laid between August and January in a well-hidden hole (dug by the female). Most eggs are infertile in captivity; only four fertile clutches have been documented. Humidity and oxygen levels (altitude) appear to be important factors in egg development. Weight and dimension of eggs, as well as hatchlings, is widely variable (47-68 g and 42-49 cm, respectively); the reason for this is unknown.
Many of the animals that are prey for Papuan monitors are important to island natives for food and economic purposes. Also, attacks on cattle and other livestock are not uncommon. If disturbed by humans, these lizards are capable of doing severe physical damage.
Negative Impacts: injures humans (bites or stings)
Papuan monitors have been utilized by natives of the island for their meat and skin, which is important as clothing and as heads for ritual drums. They are not often actively hunted, due to the inherent risks associated with finding and killing these large animals, but are often caught in traps intended for other animals.
Positive Impacts: food ; body parts are source of valuable material
Papuan monitors are large, powerful creatures that are the dominant predators in their ecosystem, with no known predators besides humans. They are predators of many smaller animals and their eggs, controlling the populations of these organisms. Wild caught Papuan monitors have been found to be infected with enteric parasites.
Commensal/Parasitic Species:
Papuan monitors are carnivorous, feeding on small animals. They are known to prey on both adult birds and their eggs (particularly Cacatua sp. and maleos (Macrocephalon maleo)). They are also known to eat small mammals (such as rodents), reptiles and amphibians, and insects, as well as carrion. They have long, sharp teeth and powerful jaws, and are known to swallow food items whole. Unlike many other varanids, they do not appear to adjust the ferocity of their attack based on prey size.
Animal Foods: birds; mammals; amphibians; reptiles; eggs; carrion ; insects
Primary Diet: carnivore (Eats terrestrial vertebrates, Eats eggs, Insectivore , Scavenger )
Papuan monitors are endemic to the island of New Guinea, both Papua New Guinea and West Papua (Indonesia).
Biogeographic Regions: australian (Native )
Other Geographic Terms: island endemic
Papuan monitors primarily reside in coastal lowland environments, mainly tropical rainforests and mangrove swamplands. Though they are typically found from sea level to 200 meters above sea level, these animals may be found in mountains up to 650 meters above sea level. They live in arboreal and terrestrial habitats, depending on availability of sunlight and prey. Since this species resides in rainforests, its optimal temperatures are high, from 29-31ºC during the day.
Range elevation: 0 to 650 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: rainforest
Lifespan of Papuan monitors in the wild is unknown. In captivity, they are known to survive for 12-20 years.
Typical lifespan
Status: wild: 12 to 20 years.
Papuan monitors are the largest known species of monitor lizard found on New Guinea, growing up to 2.5 m, with an average weight of 20 kg. They have long tails, typically twice their SVL (snout-vent length), which are rounded at the base and triangular distally. The skin is covered with non-overlapping scales, and body color is mostly black with specks of yellow, white, or green, with folds around the neck. They have round snouts with long, forked tongues used for chemoreception, and very long, vertical teeth, as well as strong claws. Males are generally larger than females, due to reproductive energy expenditures by femmales.
Range mass: 90 (high) kg.
Range length: 2 to 5 m.
Average length: 3 m.
Sexual Dimorphism: male larger
Little is known about possible predators of Papuan monitors. As they are thought to be top predators in their habitat, humans likely pose the only regular danger to these lizards, due to deforestation and the value placed upon their skins.
Known Predators:
Male Papuan monitors are aggressive, fighting (as all vanarids do) in a ritualized fashion that involves head weaving, bipedal clinching and wrestling in order to attract females; the larger a male is, the more likely he is to succeed. After combat, males will proceed in courting the female (by licking, stroking and scratching in other varnids), followed by a forceful act of mating, with the male biting the female's neck, resulting in bleeding wounds called mating marks. The female will then either comply, lifting her tail to allow the male to insert his hemipenes (one at a time, though both are used in one mating) or flip over in order to make copulation more difficult, if not impossible. Generally, female vanarids may mate with one or several males over a period of a few days.
Mating System: polygynandrous (promiscuous)
Breeding season is unknown and this behavior has not been observed in the wild. In captivity, when a male is introduced to a female, copulation nearly always takes place and eggs result. In general, varanids may lay more than one clutch of eggs per year and captive clutches of Papuan monitors typically have 4-12 eggs (although the majority of these in captivity are infertile). Size of the female seems to be linked to clutch size, with larger females producing more eggs. In captivity, eggs laying has been observed 3-4 months after copulation, with hatching taking place 20 or so days later. Male and female Papuan monitors experience varied growth patterns that illustrate this species' level of sexual dimorphism. Upon reaching sexual maturity (within 2 years of hatching), males continue to grow, whereas growth of female individuals is halted, with energy being diverted to egg production.
Breeding interval: Female vanarids may lay multiple egg clutches in a year.
Breeding season: Breeding season is unknown for this species.
Range number of offspring: 4 to 36.
Average number of offspring: 8.
Range gestation period: 3 to 4 months.
Key Reproductive Features: iteroparous ; sexual ; fertilization ; oviparous
Little is known about parental involvement of Papuan monitors after eggs have been laid. Following copulation, captive females have been noted to bury their eggs, digging holes and then filling them in such that the nests are barely visible.
Parental Investment: female parental care ; pre-fertilization (Provisioning)
Varanus salvadorii, also known as the crocodile monitor, Papuan monitor or Salvadori's monitor, is a species of monitor lizard endemic to New Guinea. It is the largest monitor lizard in New Guinea and is one of the longest lizards, verified at up to 255 cm (100 in). Its tail is exceptionally long, with some specimens having been claimed to exceed the length of the Komodo dragon, however less massive.
V. salvadorii is an arboreal lizard with a dark green body marked with bands of yellowish spots. It has a characteristic blunt snout and a very long tail. It lives among the mangrove swamps and coastal rainforests of the southeastern part of New Guinea, feeding opportunistically on everything from birds and small mammals to eggs, other reptiles, amphibians and carrion. Its large, backwards-curving teeth are better adapted than those of most monitors for seizing fast-moving prey. Like all monitors, it has anatomical features that enable it to breathe more easily when running than other lizards, and it may actually have even greater stamina than most other monitor species.
V. salvadorii is threatened by deforestation and poaching, and is protected by the CITES agreement. Little is known of its reproduction and development, as it is difficult to breed in captivity. Attempts at captive breeding have been mostly unsuccessful. In New Guinea, the lizard is sometimes hunted and skinned by tribesmen to make drums. It is described as an evil spirit that "climbs trees, walks upright, breathes fire, and kills men", yet the local people maintain that it gives warnings if crocodiles are nearby.
V. salvadorii was first described as Monitor salvadorii by Wilhelm Peters and Giacomo Doria in 1878 based on a female specimen with a snout-to-vent length of 48 cm (19 in), and a 114 cm (45 in) long tail.[5] It was subordinated to the genus Varanus under the name Varanus salvadorii by George Albert Boulenger in 1885.[6]
There are no formally recognized subspecies of V. salvadorii, but the captive reptiles market distinguishes those from Sorong, Jayapura and Merauke based on the color of their snout and the overall brightness of their color pattern.[7]
The generic name, Varanus, is derived from the Arabic waral (ورل), meaning "lizard". The term "monitor" is thought to have come about from confusion between waral and the German warnen, meaning "warning". The term "goanna" came about as a corruption of the name "iguana". The specific name, salvadorii, is derived from a Latinization of Tommaso Salvadori,[8] an Italian ornithologist who worked in New Guinea.[2]
The evolutionary history of V. salvadorii started with the genus Varanus, which originated in Asia about 40 million years ago (Mya). Around 15 Mya, a tectonic connection between Australia and Southeast Asia allowed the varanids to spread into what is now the Indonesian archipelago.[9]
Based upon DNA sequences of three nuclear and two mitochondrial genes, cladistic analysis identifies V. salvadorii as a member of a species cluster that includes the lace monitor (V. varius) and the Komodo dragon (Varanus komodoensis).[10] Morphological considerations suggest that Varanus priscus was also a member of the group.[11] Monitors apparently colonized Australasia from Asia about 32 Mya; the varius clade then arose about 17 Mya.[10] The Torres Strait separating New Guinea from Australia is less than 90 km (56 mi) long, a distance that could have been covered fairly easily with island hopping.
The largest of the seven species of monitors found on the island of New Guinea, V. salvadorii occurs in both the state Papua New Guinea and the Indonesian region of West Papua. It inhabits the high and low canopies of the lowland rainforests and coastal mangrove swamps, sometimes venturing out of these areas during floods in the rainy seasons. No detailed field investigation data are available for V. salvadorii, so the full extent of its range is unknown.[3][5] Its remote and generally inaccessible habitat is an obstacle to detailed study of this monitor in its natural habitat.[3][5]
The most characteristic feature of V. salvadorii is its blunt, bulbous snout, which makes it look different from every other monitor on New Guinea, and suggested the common name "tree crocodile".[5] The body of the lizard is dark green with rings of yellow spots.[12] The tail is banded yellow and black and is extremely long.
Its teeth are long, straight, and sharp. Its claws are prominent and strongly curved.[13] Males reach a considerably larger size than females in both weight and length, and also tend to have a more robust head.[7]
V. salvadorii is unique among extant varanid species in that the animal's tail is much longer than the snout-to-vent length in both juveniles and adults. The tail generally is 2–2.7 times the snout-to-vent length.[5][14][15]
At hatching, V. salvadorii is about 45 cm (18 in) long and they reach maturity when about 170 cm (67 in).[14] Reports of the maximal length vary greatly and are the subject of much dispute. It possibly attains the greatest length among extant species of lizards, although it is considerably less massive than the Komodo dragon.[16] V. salvadorii has been confirmed to reach up to 255 cm (100 in) in length (record by a specimen at Museum Koenig).[14][17] Some have been claimed to be much larger, including an individual from Konedobu that reportedly was 323 cm (127 in) long, one from Kikori that reportedly was 427 cm (168 in) and an individual from Port Moresby that reportedly was 475 cm (187 in) long, but these sizes are unverified.[7][16]
Claims of V. salvadorii attaining large weights also are unverified; the species is much more slender than Komodo dragons of comparable length.[16][18] The typical reported length of this species is less than 200 cm (79 in) with a matching body mass of about 20 kg (44 lb),[19][20] but such a weight is questionable for healthy (i.e., not obese) individuals of this slender, arboreal species.[7] Ten specimens were found to weigh only 5 to 6.38 kg (11.0 to 14.1 lb) at a length of 1.16 to 2.25 m (3 ft 10 in to 7 ft 5 in),[21] and a review of healthy adults in captivity found that a typical weight was up to 6 kg (13 lb).[7] The average size of V. salvadorii caught in one study was 99.2 cm (39.1 in) with a weight of 2.02 kg (4.5 lb), but these must have been young specimens.[22]
Varanus salvadorii has mammal-like aerobic abilities; a positive pressure gular pump in the animal's throat assists lung ventilation.[3][23] Unlike most lizards that cannot breathe efficiently while running, because of Carrier's constraint, the gular pump of monitor lizards enables them to overcome the effect of one lung at a time being compressed by their running gait.[23][24] The evolutionary development of the gular pump is functionally analogous to that of the diaphragm in mammals, which ventilates the lung independently of locomotion. V. salvadorii may be the species that achieves the greatest running endurance as a result of its gular pump.[3][23] Investigation supports the idea that gular breathing is an evolutionary development that masks the effect of Carrier's constraint.[23]
V. salvadorii is a highly arboreal lizard. It can hang onto branches with its rear legs, and occasionally use its tail as a prehensile grip. The primary function of the tail, however, is as a counterbalance when leaping from branch to branch.[3] As in some other Varanus species, the tail also may be used for defense, as captive specimens may attempt to lash keepers with their tails.[25] This species occasionally is seen in the pet trade, but has a reputation for aggression and unpredictability.[5] Although they are known to rest and bask in trees, they sleep on the ground or submerged in water.[3]
These monitors rise up on their hind legs to check their surroundings, behavior that also has been documented in Gould's monitors (V. gouldii).[6] They are known to exhibit a warning posture, in which they carry their tails rolled up behind them. According to native belief, they give a warning call if they see crocodiles.[6] In general V. salvadorii avoids human contact, but its bite is capable of causing infection, like the Komodo dragon's.[6] One fatality was reported from a bite in 1983 when a Papuan woman was bitten and later died from an infection.[5]
The teeth of V. salvadorii do not resemble those of other monitor species, which typically are blunt, peglike, and face slightly rearward.[3] Their upper teeth are long, fang-like, set vertically in the jawbone, adapted to hooking into fast-moving prey such as birds, bats, and rodents. Their lower teeth are housed in a fleshy sheath. In the wild, V. salvadorii is the top predator in New Guinea, feeding on birds (such as Cacatua sp.), eggs, small mammals (such as rats and bandicoots), frogs, reptiles, and carrion.[13][26][27] Natives have reported that it can take down pigs, deer, and hunting dogs, and hauls its prey into the canopy to consume it.[3] Captive specimens have been known to eat fish, frogs, rodents, chickens, and dog food.[5][28]
This species has been observed hunting prey in a unique fashion for monitor lizards.[3] Rather than following its prey to ambush it from behind, V. salvadorii may stalk its prey and anticipate where it will run, meeting it headlong.[3]
Reproduction of V. salvadorii has only been observed in captivity, so nothing is known about its reproduction in the wild. The egg clutches, comprising four to 12 eggs, are deposited around October to January, with the eggs showing a remarkable difference in dimensions, a phenomenon for which no explanation is known. Dimensions may vary from 7.5 cm × 3.4 cm to 10 cm × 4.5 cm (3.0 in × 1.3 in to 3.9 in × 1.8 in), while weight may vary from 43.3 to 60.8 g (1.53 to 2.14 oz). Most clutches laid in captivity have been infertile, and only four successful breedings have been documented thus far. Hatchlings are about 18 in (46 cm) long and weigh around 56 g (2.0 oz). Like those of many other monitors, the hatchlings of V. salvadorii are more colorful than adults, and feed primarily on insects and small reptiles.[3][29]
Varanus salvadorii is currently protected under the CITES Appendix II,[30] which requires an exportation permit for international trade. It is not listed as a threatened species on the IUCN Red List or on the Endangered Species Act.[31] It faces threats from deforestation and poaching, as it is hunted and skinned by native peoples, who consider the monitor an evil spirit that "climbs trees, walks upright, breathes fire, and kills men", to make drums .[5][13] In 2008, 52 individuals were maintained at 17 zoological parks in the United States, with an unknown number in private collections.[12]
Varanus salvadorii, also known as the crocodile monitor, Papuan monitor or Salvadori's monitor, is a species of monitor lizard endemic to New Guinea. It is the largest monitor lizard in New Guinea and is one of the longest lizards, verified at up to 255 cm (100 in). Its tail is exceptionally long, with some specimens having been claimed to exceed the length of the Komodo dragon, however less massive.
V. salvadorii is an arboreal lizard with a dark green body marked with bands of yellowish spots. It has a characteristic blunt snout and a very long tail. It lives among the mangrove swamps and coastal rainforests of the southeastern part of New Guinea, feeding opportunistically on everything from birds and small mammals to eggs, other reptiles, amphibians and carrion. Its large, backwards-curving teeth are better adapted than those of most monitors for seizing fast-moving prey. Like all monitors, it has anatomical features that enable it to breathe more easily when running than other lizards, and it may actually have even greater stamina than most other monitor species.
V. salvadorii is threatened by deforestation and poaching, and is protected by the CITES agreement. Little is known of its reproduction and development, as it is difficult to breed in captivity. Attempts at captive breeding have been mostly unsuccessful. In New Guinea, the lizard is sometimes hunted and skinned by tribesmen to make drums. It is described as an evil spirit that "climbs trees, walks upright, breathes fire, and kills men", yet the local people maintain that it gives warnings if crocodiles are nearby.
