Summer is the time that the reptiles become active and we are definitely seeing more of these fascinating creatures now that the temperatures have increased and the rains have arrived. The rains and new plant growth have increased the numbers of insects present and this has provided more food items for the lizards.
The Kruger National Park has a great diversity of lizard species. Almost 60 different species of lizards have been found in the Kruger National Park. The rocky ridges of the Lebombos provide great habitat for lizards and in the Singita Kruger Concession we have recorded numerous different species.
Taxonomically, lizards fall into the Kingdom “Animalia”, the Phylum “Chordata”, the Class “Reptilia” and the Order “Squamata”. The Order Squamata includes all lizards, snakes and amphisbaenids (worm-lizards). The Order “Squamata” is easily the most species-rich order of living reptiles and includes nearly 8 000 species worldwide.
Lizards fall into the Sub-order “Sauria” and have the following characteristics:
Most lizards have four limbs (even limbless lizards generally have internal vestiges of limb
The body is covered with scales, which are usually overlapping.
Most lizards have external ears.
Most lizards have moveable eyelids (although in most geckos and some skinks the eyelids are transparent and fused, forming a “spectacle” over the eye).
The halves of the lower jaw are fused.
The tongue cannot be drawn into a sheath (although in some families, such as Varanidae, it is retractile).
Most lizards (except chameleons, agamas and monitors) can voluntarily shed their tail and grow a new one. This is known as autotomy.
Most lizards do not produce venom (although agamas, monitors and chameleons have been shown to have salivary glands that produce toxins that have a venomous action. The southern African species are not considered dangerous to humans).
Most lizards are carnivorous / insectivorous, although some such as the giant plated lizard will feed on a limited amount of vegetation.
Most lizards lay leathery eggs, although some species lay hard-shelled eggs (e.g. geckos) and some give birth to live young (e.g. many skinks).
There are eight families of lizards that occur in southern Africa (excluding the Family Amphisbaenidae, which are considered to be closely related to lizards, but are often referred to as a separate suborder). These are:
Agamidae : Agamas
Chamaeleonidae : Chameleons
Varanidae : Monitor Lizards
Lacertidae : Lacertids / Old world lizards (bushveld lizards, sand lizards, rough-scaled lizards, mountain lizards)
Agamas tend to be plump, short-bodied lizards with thin tails and triangular heads, which are relatively distinct from the rest of the body. Although the eyes are relatively small they are quite obvious and prominent. The eyelids are movable. They have an enlarged occipital scale on the head, under which lies a pineal eye (a light-sensitive area, which is thought to control seasonal breeding). The females and juveniles are usually fairly well camouflaged. The males are often brightly coloured, particularly in the head and neck region. In some species the breeding males may develop blue heads or necks. Agamas tend to be diurnal and spend the nights in their retreats e.g. burrows in the ground or holes in trees. During the day agamas tend to be quite alert and run away from danger. Certain agamas become quite territorial and males might fight or display to one another. Many agamas feed exclusively on ants.
The southern tree agama (Acanthocercus atricollis atricollis) is commonly found in the Singita Kruger Concession and are seen regularly on the trees in and around Lebombo and Sweni Lodges.
Chameleons are unmistakable as a family. The head and body are laterally compressed and the neck is not well-defined. The eyes are turret-like with a small round opening at the top to expose the pupil. The eyes can move independently (one can face forward while the other faces backward). The limbs are long and well developed and the toes are in bundles and zygodactyl. The tail cannot be shed and is long and prehensile. It is often carried rolled up in a spiral. The tongue is club-shaped and extremely long. The tongue is shot out to capture prey (usually insects). Nearly all species are arboreal and diurnal. Chameleons are famous for their ability to change colour. This enables them to have great camouflage. They also change colour when stressed or when courting, often exhibiting brighter or darker coloration (bolder) in these cases. They move slowly, almost swaying (like leaves in the wind), when hunting. When harassed they can move quite quickly. When acting defensively they often blow up their throats (showing off the bright colours), hiss and may even bite. Most species lay eggs, although some are ovoviviparous.
The only example of a chameleon that occurs in the Lebombo Concession is the flap-necked chameleon (Chamaeleo dilepis).
Some people believe that if a chameleon bites a person, that person will change sex. This is physically impossible and definitely not true!
Varanidae: Monitor Lizards
The monitor lizards are the largest lizards in southern Africa. They tend to have relatively long necks and their heads are distinct from their necks. Monitor lizards are quite robust in shape and have long, laterally compressed tails. Their tails cannot be shed. The scales on the upper part of the body are small and bead-like. They do not overlap. The scales on the underside tend to be more rectangular and are arranged in transverse rows. Their legs are well-developed and strong. They have re-curved claws on each digit and their toes are reasonably long.
They are predominantly predatory, with the southern African species feeding on various small creatures including insects, other invertebrates, birds, bird eggs, mice, smaller lizards, crocodile eggs, snails etc. They will feed on almost anything that they can overpower. They can climb well and are sometimes found in trees. They swim well, but water / Nile monitors prefer moister habitats than rock monitors. They are oviparous and lay soft-shelled eggs in holes in trees or buried in holes underground.
Only two species are found in southern Africa and both can be found in the Singita Kruger (Lebombo) Concession. The two species are the rock / white-throated monitor (Varanus albigularis) and the water / Nile monitor (Varanus niloticus)
Some people believe that monitor lizards can insert the tips of their forked tongues into the nostrils of unwary people (possibly while they sleep) and suck out their brains. This is not true! These animals use their forked tongues to “smell” their surroundings. They pick up particles of air on the tips and insert it into an organ on the upper side of their mouths, known as the Jacobson’s Organ. With this organ they are able to chemically analyse the air and thus are able to “smell/taste” the air.
Lacertidae: Lacertids / Old World Lizards
The Lacertids are small to medium sized lizards. They tend to have a slender body and a long tail (usually longer than the body). They have well-developed limbs. The scales on the tail are often keeled and whorled around the tail. The tails can be shed and regenerated again. Most species are terrestrial and diurnal. They tend to forage actively and can be quite territorial. They feed predominantly on insects and small invertebrates.
Although we do not find many Lacertids in the concession we do, on occasion see bushveld lizards (Heliobolus lugubris). Juvenile bushveld lizards are very interesting in that they have dark black bodies with broken yellow-white lateral and dorsal stripes (typical aposematic coloration), and have light-brown tails. It is thought that the coloration of the hatchling is an imitation of the colours of the ground beetle, which is able to deliver a nasty bite and can squirt formic acid for a distance of up to 350 mm. The bushveld lizard hatchling has a very unusual stiff-legged walk that also suggests that it may be mimicking the ground beetle.
This family includes the burrowing skinks, the snake-eyed skinks, the writhing skinks and the typical skinks.
The typical skinks are generally small to fairly large lizards. The body is usually covered with rather shiny, overlapping scales. The typical skinks have long, tapering tails (usually in the region of the length of their bodies). The tails are easily shed and regenerated. Many skinks have longitudinal light coloured stripes on their body, running from the head to the tail. Skinks are usually diurnal and either actively search out their prey, which are usually small invertebrates, or lie in strategic positions and dash forward to capture passing prey. They can get quite habituated to humans. They often bask in exposed positions and will allow one to approach them fairly closely before they flee. Typical skinks often occur in fairly dense numbers and individuals often posture to one another in order to establish a form of dominance. Most of the skinks in southern Africa give birth to live young; although some lay eggs (some individuals of a species may even lay eggs while another of the same species may give birth to live young). Typical skinks tend to grow quickly and some can reproduce within a year of being born / hatched. Rainbow skinks are very commonly encountered around Lebombo and Sweni Lodges.
Gerrhosauridae: Plated Lizards
The plated lizards are generally medium to large, robust lizards. Some species, particularly those that live in grasslands and those that live on sand-dunes, have become elongated, long and thin (and have reduced limbs) to assist with movement through the grass or sand. Most plated lizards have well-developed limbs.
The heads of gerrhosaurs tend to be fairly large and covered with large symmetrical scales. The scales of plated lizards are often keeled. There is a distinct fold in the scales that tends to run from the back of the jaw to the front of the hind legs, along the sides of the lizard. Most of the plated lizards are diurnal and all are terrestrial. Some species show a fair amount of parental care for their young. The plated lizards are generally fairly slow moving lizards that are often shy. They feed predominantly on insects and other small invertebrates, but some species will also eat plant parts (particularly flowers and ripe fruit). Plated lizards tend to be fairly long-lived, slow-growing lizards.
This family of lizards is quite unusual and quite diverse in terms of numbers of species occurring in the southern African sub region. Geckos are generally small to medium sized lizards. Geckos tend to be nocturnal, although some are diurnal (e.g. the dwarf geckos). They tend to be more tolerant of colder temperatures than other lizards and can therefore be found in areas like high mountains and deserts (which get cold at night). Geckos tend to have unusually shaped feet. They are able to climb up surfaces that many other animals cannot (some species can even climb up glass). They do so by having specially adapted feet. Many geckos have pads under their toes that consist of rows of minute hairs. These pads are known as scansors and allow the feet to grip onto almost smooth surfaces. Some species of geckos even have minute claws that lie in between the scansors and are retractable. In many species of geckos the toes are almost spatulate in shape. Geckos eyes tend to be quite large (because many of them are nocturnal) and their pupils tend to have various shapes. Most geckos lack moveable eyelids. Their eyelids tend to be fused and transparent. They thus look through their eyelids. Because they do not blink they often clean their eyes with their tongues. Most geckos are cryptically coloured. The scales on the body of many geckos are small, smooth and granular, giving a fine texture to the skin. In some geckos these scales are interspersed with larger tubercles and spiny scales on the tails. Most geckos are arboreal or rupiculous (living in rocky areas), although some are terrestrial. Some geckos are able to store fat reserves in their tail. Gecko tails are usually easily shed and are easily regenerated.
Some species of geckos are commensal with man and can be found in buildings, particularly near lights that attract insects. Geckos are often vocal and communicate with each other by sound. Some species of gecko are parthenogenic and can produce fertile eggs without mating. Geckos tend to be oviparous and lay clutches of two hard-shelled eggs, which are laid under the bark of trees, in cavities in logs or in holes dug in the sand. They store calcium for their eggs in special neck glands called endolymphatic sacs. Geckos tend to shed their skins in patches, which they eat.
The Cordylids include sungazers, girdled lizards, crag lizards, flat lizards and grass lizards.
The most common Cordylid lizard found in the Singita Kruger Concession is the Wilhelm’s flat lizard (Platysaurus intermedius wilhelmi). Flat Lizards are generally found in rocky areas and as their names imply they often hide in flat crevasses and cracks between rocks. Most flat lizards are sexually dimorphic and the males are often brightly coloured, while the females are more cryptic with pale stripes running parallel along the back. The male Wilhelm’s flat lizard is dark brown, with a black throat and belly and a bright red tail.
Image Order & Details:
Southern rock monitor
Southern tree agama (male breeding colours) – cover image
Southern tree agama
Southern rock monitor
Juvenile bushveld lizard
Rainbow skink (male)
Rainbow skink (female)
Yellow-throated plated lizard
Rough-scaled plated lizard
Giant plated lizard
Wilhelm’s flat lizard (male)
Wilhelm’s flat lizard (female)
Images by Brian Rode, Chantelle Venter and Margaux Le Roux