Varanus Mertens [1] ( lat. Varanus mertensi ) - a species of lizards from the family of lizards , common in Australia . Named after the German biologist Robert Mertens (1894-1975).
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| Varanus mertensi Glauert , 1951 |
Content
Description
Appearance
The Mertens monitor lizard can reach a length of 160 cm. The Mertens monitor lizard has a long tail (up to 183% of the body length from the tip of the muzzle to the cloaca), which is very laterally compressed and has a high medial keel, which indicates adaptation to life in water. The location of the nostrils in the upper part of the muzzle is also a sign of a semi-aquatic lifestyle. The distance between the nostrils and the eye is approximately two times greater than the distance between the nostrils and the tip of the muzzle.
The main coloration of the upper body of Mertens monitor lizard is dark olive or dark brown to black. Numerous creamy or pale yellow spots, surrounded by black scales, are randomly scattered on the back. The lower surface of the body is white to yellowish with gray spots on the throat and bluish-gray transverse stripes on the chest and belly. The throat is light yellow. A narrow bluish strip runs along the upper jaw, under the ear, along the neck to the shoulder girdle. The body scales are small and smooth. 150-190 rows of scales are located around the middle of the body. The tail scales are slightly keeled and do not form regular rings, since the scales on the lower side are larger than on the upper.
Distribution
The distribution of Mertens monitor lizard is limited to the tropical north of Australia. Its range extends from the east of Western Australia in the west to western Queensland ( Cape York ) in the east. Since these animals are very strongly associated with water, the distribution area is not continuous.
Lifestyle
Most of the time, the Mertens monitor lizard spends in the water and rarely moves more than a few meters from it. These monitor lizards are found in rocky gorges, along slowly and quickly flowing rivers, near reservoirs, swamps, lagoons and billabongs . Often sympatric with combed crocodiles ( Crocodylus porosus ). During the rainy season, much more habitat is available for them, and many monitor lizards during this period move to temporary water bodies. Sometimes animals climb on rocks or tree trunks lying on the shore for basking . Often lizards bask in the sun, lying in water plants. In danger, lizards hide in the water. May remain under water for a long time.
An important adaptation of monitor Mertens to a semi-aquatic lifestyle is its ability to remain active at low body temperature. [2]
Like other large monitor lizards, Mertens monitor lizard can stand on its hind legs when threatening or participating in a ritual battle.
Nutrition
Mertens’s lizard extracts most of its food in water. It feeds on crustaceans ( crabs , river crayfish , shrimps and amphipods ), aquatic and terrestrial insects ( orthoptera , dragonflies , bugs and bugs ) and their larvae , spiders , fish , frogs , reptiles , mammals , as well as bird eggs and turtles . These lizards collect food waste from among the garbage and probably eat carrion when the opportunity presents itself.
It was observed that at the mouth of the river in the Kakadu National Park, Mertens’s lizard, about 100 cm long, hunted fish in a shallow pond, using a curved arc tail to drive the fish closer to the mouth, and grabbing prey from above. [3] To swallow large prey, Mertens monitor lizard crawls ashore.
Reproduction
Little is known about the breeding of this species in the wild. There are no noticeable external differences between males and females. Monitors kept in outdoor enclosures in Queensland laid their eggs in March, burying them in a nesting hole about 50 cm deep. Most breeding occurs in the dry season, but can sometimes occur at other times of the year. In captivity, clutches containing up to 14 eggs were observed. The size of eggs is 6x3.5 cm. Newborns reach 24-27 cm in length and weigh about 24-28 g.
Classification
Varanus mertensi is part of the subgenus Varanus . Despite the sometimes strong isolation of individual populations, the phenotype is almost unchanged. There is evidence that lizards from Mount Isa in western Queensland have a more rounded snout than animals from the western part of the range. Subspecies not described. [3]
Notes
- ↑ Ananyeva N. B. , Borkin L. Ya. , Darevsky I.S. , Orlov N.L. The five-language dictionary of animal names. Amphibians and reptiles. Latin, Russian, English, German, French. / edited by Acad. V. E. Sokolova . - M .: Rus. Yaz., 1988 .-- S. 269. - 10,500 copies. - ISBN 5-200-00232-X .
- ↑ www.mampam.com
- ↑ 1 2 www.monitor-lizards.net Archived on January 1, 2010.
See also
Monitor lizards
Links
Literature
- Darevsky I.S. , Orlov N.L. Rare and endangered animals. Amphibians and reptiles: Ref. allowance / ed. V. E. Sokolova . - M .: Higher school, 1988. - S. 288. - 463 p., [16] p. silt - 100,000 copies. - ISBN 5-06-001429-0 .