Madagascar sand iguana
| Madagascar sand iguana | ||||||||||||
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Chalarodon madagascariensis |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Chalarodon | ||||||||||||
| Peters , 1854 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Chalarodon madagascariensis | ||||||||||||
| ( Peters , 1854) |
The Madagascar sand iguana or small Madagascar iguana ( Chalarodon madagascariensis ) is the smallest member of the Madagascar iguanas family with a maximum length of 23 centimeters . The genus Chalarodon is endemic to Madagascar .
distribution and habitat
The species mainly inhabits near-coast, semi-arid to arid regions and almost exclusively open or only very sparsely vegetated habitats with a sandy subsoil (sand dunes) in the province of Toliara (also Toliary or Tuléar), as well as in the southwest of the provinces of Fianarantsoa and Majunga in southwest Madagascar. They are rarely found in thorn bush regions.
features
The males reach a head-trunk length of up to 87 millimeters, the females up to 67 millimeters (source: Peters, 1854). The total length is around 20 cm (up to a maximum of 23 cm for males, up to 17 cm for females). The tail is around 1.5 times as long as the head-torso length . The coloration of both sexes depends on mood and sexual maturity. In juvenile and in the morning not yet warmed iguanas the colors brown and beige dominate. In the case of adult , well-warmed animals, on the other hand, the males in particular adorn themselves with intensely yellow and orange drawing elements on a beige background. The females are generally a little paler in color. Only during courtship and territorial disputes among males, a ridge up to 5 millimeters high appears in male iguanas, which is lined with jagged scales. The long hind legs enable the animals to make extremely fast spurts when hunting for insects. The long toes, especially on the hind legs, make it easier for the iguanas to dig in and walk on the loose sandy soil.
Way of life and behavior
The Madagascar sand iguanas live exclusively on the ground. At ground surface temperatures of over 60 degrees Celsius they chase after small insects. They spend the hottest time around noon (especially in summer) and the nights in the ground. The self-dug underground passage system has several entrances. The females are predominantly involved in creating the corridors.
Since the temperatures in this region neither rise nor fall too much, neither in summer nor in winter, the iguanas can be found all year round. The animals only retreat to the ground for a mostly short period of rest only when no feeder insects can be found because of the dry conditions. Here they spend the time completely inactive. As soon as the conditions have improved again, the animals are active again.
Territorial behavior
The males are territory-forming. They defend their territory of several square meters (diameter: around 10 meters!) Against any other male. They show typical threatening gestures in arguments. The animals slowly wag their tails, open their mouths threateningly and inflate their throat pouches. They nod their heads and often roll their tails over their bodies as well. The colorful drawing elements increase in their color intensity. If this imposing behavior does not bring the desired effect, arguments arise in the course of which the animals can injure themselves with bites. This only happens when the inferior male lacks an alternative. The first territorial disputes can already be seen in semi-adult males. Young animals of both sexes as well as adult females are very well tolerated with each other and with adult males.
nutrition
The Madagascar sand iguanas are primarily insectivores . A wide variety of small insects are consumed, which can safely identify the iguanas even at a greater distance and hunt them with the help of rapid spurts. Their fine teeth help to hold the insects firmly in place. In addition to the animal diet, plant foods are also occasionally consumed, especially in the form of succulent leaves and roots. The vegetable food may serve to supplement the water balance, but water is also drunk if it is available at all after the rare rainfall. Usually, however, water is licked off as dew in the morning. In addition, the very low water requirement is covered by the feed insects. If the conditions are too dry in their underground tunnels, the iguanas can manage without food and water for more than a year. Presumably in inhospitable aboveground conditions they absorb soil or air moisture through their skin and reduce their entire metabolism to a minimum. As soon as the conditions have improved, the iguanas can be found above ground again.
Reproduction
The male impresses the female by wagging its tail and intensifying the colors. The female who is not ready to mate answers this by rolling up her tail. However, if the female is ready to mate, it in turn wags its tail, whereupon the male immediately takes the opportunity to mate . It holds the female in place with a bite in the neck. The pairing itself only takes a few seconds. The subsequent pregnancy lasts 14 to 20 days. Only 2 eggs develop at a time. The 10 to 12 millimeter long eggs are laid in the underground passages and not buried. At a temperature of around 28 degrees Celsius, the 20 millimeter long young hatch after 68 to 72 days.
Life expectancy
The small Madagascar iguana can live to be more than 6 years old in terrarium conditions.
Danger
The Madagascar sand iguana is adapted to anthropogenic , i.e. human-influenced habitats. The species is still very common locally and can occur in high population densities. It is widespread in the south and southwest of Madagascar and shows a constant population size. The Madagascar sand iguana is therefore classified as Least Concern (LC ) by the International Union for Conservation of Nature and Natural Resources (IUCN) .
literature
- Charles P. Blanc: Etudes sur les Iguanidae de Madagascar. In: Oecologia. Volume 2, No. 3, 1969, pp. 292-318. doi: 10.1007 / BF00386115
- Charles P. Blanc, Charles C. Carpenter: Studies on the Iguanidae of Madagascar III. Social and Reproductive Behavior of Chalarodon madagascariensis. In: Journal of Herpetology. Volume 3, No. 3/4, 1969, pp. 125-134. doi: 10.2307 / 1562952
- Charles P. Blanc, F. Blanc, J. Rouault: The Interrelationships of Malagasy Iguanids. In: Journal of Herpetology. Volume 17, No. 2, 1983, pp. 129-136. doi: 10.2307 / 1563453
- Frank Glaw , Miguel Vences : A Field Guide to the Amphibians and Reptiles of Madagascar. 3. Edition. Vences & Glaw, Cologne 2007, ISBN 978-3-929449-03-7 .
- Friedrich-Wilhelm Henkel, Wolfgang Schmidt (ed.): Amphibians and reptiles of Madagascar, the Mascarene, Seychelles and Comoros (= DATZ atlases. ). Ulmer, Stuttgart 1995, ISBN 3-8001-7323-9 .
- Uwe Schlüter: Madagascar iguanas - way of life, care and reproduction . KUS-Verlag, Rheinstetten, 2013, ISBN 978-3-9808264-8-8 .
Individual evidence
- ↑ Chalarodon madagascariensis in the Red List of Threatened Species of the IUCN 2013.2. Posted by: M. Vences, 2011. Retrieved January 29, 2014.
