Namibia Post recently issued a new stamp series portraying five interesting Namibian gecko species. Belonging to the Gekkonidae family, these wonderful, enigmatic little creatures are worthy subjects for depiction, whether by paintbrush, pen or camera.
Amongst their most striking features are their feet (which in most species look more like four tiny hands) and their eyes – large, strange and fascinating eyes, with vertical cat-like pupils. With such mystical eyes, how do geckos see the world?
Most geckos do not have moveable eyelids. Instead, their eyes are permanently open, covered by transparent spectacles (evolved from the eyelids), which they can lick clean with their long tongues.
Geckos are famous for their climbing skills. Many species have the ability to run confidently across smooth, vertical or even overhanging surfaces. Contrary to popular belief, though, they do not have suction cups on their toes. Instead, their amazing grip is ensured by a unique arrangement of small scales with minute hairs known as scansors. With these, they find a hold on the tiniest irregularities and fissures of surfaces as smooth as glass.
Most geckos are nocturnal, although quite a number of Namibian species are active during the day. Geckos can withstand much lower temperatures than many other reptiles and may be active on cold desert nights or high up on cool mountain peaks. Geckos are generally shy and secretive, with most species being cryptically coloured and extremely well camouflaged. Because of such attributes, many geckos are poorly known and new species are still being discovered today.
Geckos are oviparous (reproducing through eggs which hatch outside the female’s body), and usually lay one or two hard-shelled eggs in secluded cracks or burrows. They are most common in deserts, and Namibia has a diverse gecko fauna with a high degree of endemism.
The Festive Gecko (Narudasia festiva) is a tiny but striking gecko that is endemic to central and southern Namibia. The genus Narudasia contains only this one known species. It is a slender reptile with long, thin toes that lack adhesive scansors. It is agile and active, darting across rocks after insects in sudden, short flurries. It is diurnal and is most active during the early mornings and late afternoons, but is easily overlooked. Its sudden bursts of movement and its bright orange tail are all that tend to give away its presence. It lives on boulders and rock faces in arid country.
The chattering, clicking call of barking geckos at dusk is
characteristic of summer evenings in many of the drier parts of
Namibia. As the sun nears the horizon and long shadows fall across the
land, one animal will start with a timid ‘tjick, tjick, tjick’, soon
answered by others, until calls can be heard from all around. The
endemic Koch’s Barking Gecko (Ptenopus kochi) is a desert dweller,
living in the vegetated dunes and interdune spaces of the central and
southern Namib. Males advertise their territory and attract females by
calling from the entrance to their elaborate burrows. It is possible to
lure the geckos out of the burrow by imitating their call.
Self-confident and ready to defend its territory, a male will dart out
of its hole to chase off the perceived intruder – only to come face to
face with an opponent of unimagined proportions. Undaunted, it may
approach to within centimetres to investigate its foe.
As the name suggests, Namib Day Geckos are day-active denizens of the
Namib Desert, occurring in Namibia and southern Angola. Bradfield’s
Namib Day Gecko (Rhoptropus bradfieldi) is endemic to the central
Namib. These geckos hunt insects in the cool shadows of overhanging
rocks or along the edges of rock pools, often congregating in some
numbers. They have up to 11 scansors beneath their long toes and are
excellent climbers, leaping confidently across cracks or from boulder
to boulder – hanging upside down. They will often chase each other in
disputes of dominance, uttering high-pitched squeaks.
The Giant Ground Gecko (Chondrodactylus angulifer) is a giant dwarf.
While it is large for a gecko, it is still a rather small reptile. It
has a sturdy, cylindrical body, unusual amongst geckos, and a large,
short-snouted head with big, bulging eyes. When alarmed, it will stand
tall and stiff legged and curl its tail up over its body. The
sub-species C. a. namibensis is endemic to the Namib Desert. Here it
lives on gravel plains and sandy flats, spending its days in short
burrows dug anew each morning. It is active at night, hunting for
insects and smaller reptiles. It has broad, short-toed feet without
scansors and is not an active climber. The Giant Ground Gecko is the
only species in the genus Chondrodactylus.
The thick-toed geckos (genus Pachydactylus) are locally the best-known
group of the Gekkonidae family and are characteristic of Southern
Africa. These are the ‘typical geckos’, with fattened bodies,
triangular heads with prominent eyes, and feet with thickened toe tips.
The toes are equipped with scansors that make the geckos excellent
climbers. They commonly inhabit houses, ships and other human
structures. The Velvety Thick-Toed Gecko (Pachydactylus bicolor), a
beautiful, small and slender gecko, is another Namibian endemic. It is
nocturnal and lives on rock outcrops across central and north-western
Namibia.
The Web-Footed Gecko (Palmatogecko rangei, depicted on the First Day
Cover) is a mysterious creature, at home on the windblown sands of the
Namib. Its large, dark eyes seem bloodshot and stand out like jewels on
the pale, delicate face. Its smooth, gently mottled skin appears
translucent and its feet are webbed to aid digging and movement on
loose sand. It spends its days in a tunnel dug into the sand and
emerges late at night to hunt insects and spiders, even on surprisingly
cold and windy nights.
Text and artwork by Helge Denker
