Bengal monitor
| Bengal monitor | ||||||||||||
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Bengal monitor ( Varanus bengalensis ) |
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| Scientific name | ||||||||||||
| Varanus bengalensis | ||||||||||||
| ( Daudin , 1802) |
The Bengal monitor ( Varanus bengalensis ) is a species of reptile from the genus of monitor lizards ( Varanus ). The species reaches lengths of 1.5 meters on average, is widespread in southern Asia and feeds mainly on small, invertebrate animals.
Systematics
The first description was in 1802 by François-Marie Daudin , the type locality is Bengal (India). John Edward Gray described the species Varanus nebulosus (type locality Java ) in 1831 , which was then classified by Robert Mertens in 1942 as a subspecies of Varanus bengalensis . Meanwhile, the species status for Varanus bengalensis nebulosus is being discussed again; Böhme & Ziegler (1997) reported a sympatric occurrence of the subspecies on Phuket and called for an elevation in the species status.
distribution and habitat
The Bengal monitor inhabits large parts of South Asia from southeastern Iran to large parts of Pakistan and India , Sri Lanka , Bangladesh , Nepal , Bhutan , southern China , Burma , Thailand , Laos , Cambodia , Malaysia , and Sumatra to Java. The species does not reach the Lesser Sunda Islands or Borneo . The subspecies V. b. bengalensis inhabits the western, V. b. nebulosus the eastern parts of the distribution area. A precise geographical boundary between the subspecies is not recognizable. The preferred habitat is light forest on rivers and floodplains. The species occurs up to 1500 m above sea level.
features
The average size for males is given as a total length of 1.5 m with a head-torso length of 58 cm and a weight of 2.7 kg. The species shows a sexual dimorphism in terms of body size : females remain smaller than males and are on average 1.2 m long, with a head-torso length of 46 cm and a weight of 1.5 kg. The maximum achievable size is very variable within the distribution area: In Bangladesh it is 1 m, in Sri Lanka 1.4 m, in Malaysia 1.6 m and in Burma in exceptional cases up to 2.4 m. The basic pattern of the species is dark in color with a light pattern. The nostrils are slit-shaped and closer to the tip of the snout than to the eye. The tail is flattened on the sides and has 2 rows of keeled scales on the top.
The two subspecies show not only differences in the scaling, but also differences in color:
- V. b. bengalensis are black, dark gray or brown, and have a variable, lighter pattern on their back.
- V. b. nebulosus are lighter in color, light gray to dirty yellow with variable speckles.
Way of life
The Bengal monitor is solitary, diurnal and mainly dwells on the ground, but can also climb and swim if necessary. In the tropical regions of the range, the species is active all year round, but in more northerly areas a dormant period is inserted in the cold months. The average body temperature is 32.6 ° C, but ranges from 22.1 to 40.2 ° C. The Bengal monitor is an active hunter who spends most of the time looking for prey. It is a generalized carnivore and feeds mainly on invertebrates such as insects , spiders , scorpions , centipedes , crustaceans and snails. In addition, vertebrates such as fish, frogs, lizards, snakes, birds, small mammals and eggs are consumed by birds and reptiles , albeit less often . Bengal monitor lizards also regularly eat carrion.
In captivity, sexual maturity is reached after 3–4 years, in nature it probably takes 5 or more years. In India, the mating season is in the rainy season in June and July, the average of 20 eggs are laid in August. Nests are made in embankments, or the eggs are laid in hollow tree stumps or termite mounds . The incubation lasts over the winter, the young hatch in March. Young animals from termite mounds often stay long with the mounds and use them as shelter. The young animals are more tree-dwelling than the old ones. Young animal mortality is high, with around half dying before they are two years old.
Danger
The IUCN Red List of IUCN classifies the Bengal monitor as Concern ( least concern a), although the stocks decrease to date; detailed inventory estimates are not available. Habitat destruction is not a major threat due to the adaptability of the species, but the species is hunted in large parts of its range as a supplier of leather and meat, or processed into traditional medicine. The species is listed on Appendix I of the Washington Convention on the Protection of Species ; according to the CITES census, only 148 living specimens were exported for the pet trade between 1975 and 2005. Live exports are currently not a threat due to the high protection status in Appendix I.
swell
- ER Pianka (2004): Varanus bengalensis . In: ER Pianka & DR King (Eds.): Varanoid Lizards of the World , pp. 157-160. Indiana University Press, Bloomington & Indianapolis. ISBN 0-253-34366-6
Individual evidence
- ↑ Varanus nebulosus in The Reptile Database
- ↑ a b Varanus bengalensis in the endangered Red List species the IUCN 2010. Posted by: Papenfuss, T., Shafiei Bafti, S., Sharifi, M., Bennett, D. & Sweet, SS, 2009. Accessed January 12, 2011.
- ↑ AP Pernetta (2009): Monitoring the Trade: Using the CITES Database to Examine the Global Trade in Live Monitor Lizards (Varanus spp.) . Biawak 3 (2), pp. 37-45
