Fotos

Rock Agama
Goegap Natural Reserve, Springbok:

While the snakes are shy and can hardly be spotted, the lizards appear much more conspicuous on the field site. Up to 34 species of skinks, lizards, agamas, chameleons and geckos may occur in Goegap and some of them are part of our daily life like the striped mice, bush Karoo rats and elephant shrews.

So are in particular the geckos which are famous for their ability to “stick” to seemingly smooth surfaces thanks to their unique toe-tips. These are covered with groups of scales with tiny hairs and by this amplify the attractive forces between the surface and the animal. From the beginning of spring numerous Bibron´s geckos (Pachydactylus bibronii) come close to our research station for foraging. When it is getting dark these normally nocturnal animals start sitting on walls, doors, windows and even underneath ceilings waiting for insects – especially moths – which are attracted by the inside lights. When the temperature rises more and more of them are showing up slowly “taking over” the research station. Through small chinks or short-time opened doors and windows they easily get inside the house so that in a sudden you have to share your room with a new roommate which from now on will enrich your sleep with its social interactive chirping sounds.

The Namaqua sand lizards (Pedioplanis namaquensis) are not as confiding as the geckos but unlike them they are omnipresent in the field site during daytime. Contrary to their name these slender and amazingly fast lizards which grow only up to 500 mm from the snout to the beginning of the long tail also occur in the Western Cape and parts of Namibia and Botswana. Sometimes it seems as if they are absolutely unable to stand still and in fact they are always ready for a little race against these strange big bipeds sometimes coming along the sandy paths. Like many lizards this species also has a colourful tail which it can shed when being attacked by a predator and which will grow again later on. Another remarkable characteristic you can usually watch them waving one of their forelegs, either to cool them down on the hot desert-sand or as a kind social interaction with their conspecifics.

But certainly the large southern rock agama (Agama atra) is the most beautiful reptile occurring in Goegap. Especially the breeding males – appearing in shiny blue with a bright stripe on the back – are very conspicuous and even attract attention in the colourful period of the wildflower display in spring. But also the females with their orange-yellow body and greenish-blue head are an optical pleasure. Thereby, both sexes are able to change their colour to improve their camouflage. This agama also shows an very interesting territorial behaviour: they maintain comparatively large territories inside which males and females form well-defined hierarchies so that there is always a dominant male and female. The dominant male usually perches on the highest point of his territory, push-up-like nodding his brightly coloured head as a signal for lesser males but also females. Looking at their size it is finally remarkable that the subspecies Agama atra knobelli which occurs in northern parts of Namaqualand and southern Namibia and grows up to 140 mm without the tail becomes noticeably larger in both sexes than its relatives which you can find throughout most parts of South Africa. Obviously, living inside a semi-desert like the Succulent Karoo is not as bad as it seems. By the way, there is a big disadvantage for agamas but also chameleons and monitors compared to other types of lizards because unlike them a tail which was once shed will never grow again.