Striped-headed bearded dragon
| Striped-headed bearded dragon | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Striped-headed bearded dragon ( Pogona vitticeps ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Pogona vitticeps | ||||||||||||
| ( Ahl , 1926) |
The striped-headed bearded dragon or colored bearded dragon ( Pogona vitticeps , pogon [gr.] = Beard; vittatus [lat.] = Striped; -ceps from caput [lat.] = Skull / head) is a species of lizard from the genus of bearded dragons ( Pogona ) in of the agamen family (Agamidae).
features
Striped-headed bearded dragons are large, powerfully built and dorsoventrally strongly flattened bearded dragons. They reach a head-trunk length of about 250 mm and a tail length of up to about 300 mm. The "beard" is well developed, but it is less pronounced than that of the Eastern Bearded Dragon ( Pogona barbata ). Both front and rear legs are short and appear strong. The scaling varies depending on the body area: Spines can be seen on both sides of the beard and in the throat region. Further rows of spines are located above the eardrum , on the back of the head, at the corners of the mouth and along both sides to the tail. The lateral spines in particular appear rather soft and rubbery when touched. Enlarged keeled scales are scattered in the finer dorsal scales. The ventral scales are also keeled. The striped-headed bearded dragon has 9–19 pre-anofemoral pores, which are used to set scent marks.
The striped-headed bearded dragon has a light to dark brown / blackish coloration, but there are also gray-brown, reddish and yellow specimens. For example, animals from the area around the Eyre Peninsula turn red when excited. There are also specimens with red heads or red eyes. In terms of coloration, the striped-headed bearded dragon is therefore the most variable of all bearded dragon species. A dark, lightly demarcated stripe, the bridle of the eye, runs from the eardrum to the eyes. The belly is usually light in one color with sometimes light shading or spots. The tail is banded and, unlike the eastern bearded dragon, regularly scalyed. The striped-headed bearded dragon has a clear pattern in the form of lighter and darker color segments along the spine . When threatening gestures, the beard is spread apart with the help of the hyoid bone apparatus and turns black. In some specimens, the rest of the body is also significantly darker. The oval ear openings are clearly visible.
In addition, it has been observed in wild animals in Australia that they are subject to a temperature-dependent sex change. The reason for this is not yet known.
distribution and habitat
The striped-headed bearded dragon inhabits eastern central Australia . The large distribution area includes the southwestern Queensland , the southeastern Northern Territory , the western New South Wales , the northwest Victoria and the eastern South Australia . The striped-headed bearded dragon inhabits semi-arid forests and dry forests and prefers areas with high solar radiation.
Way of life
Striped-headed bearded dragons like to sit on stones, stumps, fence posts and other elevated places that are mostly left only to eat. The colder the environment, the darker the animals are and the more inactive they behave. Only when they have warmed up sufficiently with the help of the sun's rays does the color light up and activities such as hunting, eating, digesting and social interactions are carried out. As soon as the body temperature has dropped below a certain threshold, a sunny place has to be found again. If it gets too hot, the animals seek the shade and pant with their mouths wide open to generate evaporative cooling.
Male animals behave territorially and defend their territory. If another male enters the area , the owner nods his head and soon afterwards splays his beard. Younger and weaker intruders then usually withdraw voluntarily and nod their heads; However, specimens of about the same strength do not react and thus provoke a fight. First, both opponents inflate their bodies and flatten them to the side in order to make the body outlines appear larger. After circling the enemy several times, the animals finally bite into each other. The opponents try to grab the root of the tail. If this succeeds, the inferior animal is lifted up and shaken. This is repeated until the weaker bearded dragon appeases the victor with circular movements with its front legs. The tail is often torn off or mutilated in these fights.
In winter, when the temperatures drop below 20 ° C, the striped-headed bearded dragon hibernates for two months in a protected roost. The animals do not sleep all the time, but can get up, eat and move in brief phases of activity.
Bearded dragons have an omnivorous diet, i.e. they consume plant and animal food. Everything that can be overwhelmed is eaten, for example insects , rodents, frogs, invertebrates , young birds and smaller lizards (including conspecifics). Young animals mostly feed on animal food. In adult specimens, this makes up only about 20% of the amount of food consumed, the remaining 80% consists of seeds and plant parts.
Reproduction / life expectancy
Bearded dragons are sexually mature from one to two years. After mating, the female lays 15–30 eggs in a small pit. After around 65 days the young hatch. You are immediately independent.
Bearded dragons can live to be 15 to 20 years old in nature. In captivity they are mostly around 10 years old.
research
The striped-headed bearded dragon is a model animal for research into sleep in reptiles.
literature
- Gunther Koehler, Karsten Grießhammer, Norbert Schuster: Bearded Dragons. Biology, care, breeding, diseases. Herpeton-Verlag Köhler, Offenbach 2004, ISBN 3-936180-04-0 .
- Thomas Wilms , Karsten Grießhammer: Basics of keeping Pogona vitticeps. In: Draco. No. 22, 2005, ISSN 1439-8168 , pp. 20-27.
- Gunther Schmida: Considerations on the East Australian Bearded Dragons. In: Draco. No. 22, 2005, pp. 46-53
- Steve Wilson, Gerry Swan: A complete guide to the reptiles of Australia. 2nd Edition. New Holland Publishers, Sydney et al. 2008, ISBN 978-1-877069-46-8 , pp. 350-351.
- Peter-Maria Müller: Bearded Dragons. The genus Pogona. Appropriate keeping, care and breeding. Natur-und-Tier-Verlag, Münster 2010, ISBN 978-3-86659-094-6 .
Individual evidence
- ↑ Holleley, CE, O'Meally, D., Sarre, SD, Graves, JAM, Ezaz, T., Matsubara, K., Azad, B., Zhang, X & Georges, A. (2015). Sex reversal triggers the rapid transition from genetic to temperature-dependent sex. Nature , 523 (7558), 79-82. http://www.nature.com/nature/journal/v523/n7558/full/nature14574.html
- ↑ Mark Shein-Idelson et al .: Slow waves, sharp waves, ripples, and REM in sleeping dragons. In: Science . Volume 352, No. 6285, 2016, pp. 590-595, DOI: 10.1126 / science.aaf3621
- ↑ Bearded dragons in deep sleep. on mpg.de, from April 28, 2016
Web links
- Pogona vitticeps in The Reptile Database
- Terrarium keeping of bearded dragons on www.Reptilienland.com