Giant girdled lizard - SANBI (2022)

Derivation of scientific name

Named after its relative size in the group of girdled lizards. It is the biggest species in the group. The genus, Smaug, is named after the legendary dragon of the same name in the novel ‘The Hobbit’ by J.R.R. Tolkien.

Common names

Sungazer, girdled lizard, giant zonure (Eng.); ouvolk (Afr.) – ouvolk is also used for other girdled lizard species in Afrikaans.

Sungazers are the largest lizards in the girdled lizard group, which belong to the family Cordylidae, containing more than 50 species (Frost et al. 2001). Their entire bodies are covered in scales armoured with spines (Losos et al. 2002). They have a habit of looking up towards the sun, which gave them the common name ‘sungazers’.

How to recognise a giant girdled lizard

Smaug giganteus, formerly known as Cordylus giganteus, is the largest lizard in the girdled lizard group. Van Wyk (2000) has measured adults to be on average 22 cm long. The longest recorded sungazer was measured close to 40 cm long (McIntyre 2006). Their bodies are almost completely covered in spiny scales. They have four large spiny scales at the back of the head (EWT 2013) and about four or five scales protruding on the side. Scales on the dorsal side are relatively larger than lateral scales, which in turn are larger than scales underneath.

The tail is covered by thick, large, spiny scales decreasing in size from the base to the tip. Sungazers are dark brown to light brown in colour on the dorsal side and straw-coloured/yellow underneath (EWT 2013). Baby sungazers look the same as adults with the exception that baby sungazers sometimes have patches of orange brown colouring (EWT 2013). Males are generally similar to females in appearance. The only noticeable differences are that males have raised scales on the side of their forelimbs, which females don’t have (Fogel 2000).

Smaug giganteus, like other girdled lizards, use various methods for protection. The spiny scales covering their bodies act as protective armour against predators (Losos et al 2002). They don’t normally venture away from their burrows, which they sprint to whenever they are threatened and also use their tails when inside the burrows, to deter intruders (Fogel 2000). They swing their heavily armoured tails, which may draw blood, at the intruder.

Getting around

Smaug giganteus have four limbs that end with pronounced digits that have relatively long nails. As burrowing lizards (Van Wyk 2000), the long nails make it easier to make burrows and to move around their grassy Highveld habitat.

Giant girdled lizard - SANBI (1)

Communication

Smaug giganteus are social lizards that live in groups (Gibbons 2014). Even in captivity they show social behaviour, where females tend to share a burrow while males exchange burrows occupied by females (Fogel 2000). Their socialism is further evidenced by the presence of epidermal glands in the femoral and cloacal glands, which are glands known for their social role in lizards (Louw 2007). This means sungazers can secrete chemicals (hormones) for communication.

Distribution

Smaug giganteus are endemic to South Africa (Van Wyk 2000). They are limited to a small area covering three provinces (Bates et al. 2014). The main and stable population is found in the northern parts of the Free State and smaller populations are found in the southwestern parts of Mpumalanga and the western parts of KwaZulu-Natal.

Habitat

Smaug giganteus are diurnal (active during the day) lizards (EWT 2013) limited to the Highveld grassland (Van Wyk 2000). They are one of the few terrestrial cordylids that inhabit flat or sloping Highveld grasslands (Bates et al. 2014). They live in self-excavated burrows, although they can be opportunistic and inhabit empty burrows.

Food

Many cordylid species are ambush foragers (Cooper 1997). They spend most of their time sitting (or standing) in one place, waiting for prey to come along. Smaug giganteus also use the same method to forage. They usually remain close to their burrows as they wait for prey. They feed on invertebrates, mostly insects, preferring beetles above all else (Van Wyk 2000). Foraging is at its highest intensity during spring and summer (September to March) and at its lowest during autumn and winter (April to August), which is their hibernation period (Van Wyk 2000).

Giant girdled lizard - SANBI (2)

SEX and LIFE CYCLES

Sex

Smaug giganteus live in separate colonies of males and females, usually in close proximity within the same area (Gibbons 2014). Males and females are generally similar morphologically. You can tell them apart by looking under their front limbs. The males have pronounced, raised scales that females lack (Fogel 2000). Male access to females is made easier by their living within the same area, close to the females’ burrows. It’s estimated that an area may contain a mean burrow density of 6.14 individuals, with a standard deviation of 0.87 containing 1.83 lizards per burrow (Parusnath 2014).

Reproduction in Smaug giganteus is almost completely seasonal (Van Wyk 1994). It reproduces biennially (once in two years) or triennially (once in three years). Males and females of Smaug giganteus go through physiological reproductive changes throughout the year as the seasons change. These physiological reproductive cycles support the idea of most reptiles being active in spring/summer and hibernating in autumn/winter. In the case of Smaug giganteus, reproductive changes that allow mating to take place starts in spring, at the end of winter and continues throughout until around mid-autumn, just before winter or hibernation.

Male sungazers show testicular revival and growth in spring when it starts getting warmer (Van Wyk 1994). This is accompanied by an increase in testosterone levels. The increase in testosterone levels stimulates the production of reproductive cells (sperms). The reproductive cells are then stored in the ducts (tube like vessels) of different sizes in the enlarged testicles. Testicular growth and reproductive cell production reach their peak around late summer/mid-autumn, which is peak mating time (Van Wyk 1994).

As winter approaches, mating stops and the physiological reproductive changes start to regress. Testicular growth and the increase in testosterone level are associated with increasing ambient temperatures and regression is associated with decreasing ambient temperatures (Van Wyk 1994).

Female sungazers are viviparous (Van Wyk 1991). This means they give birth to live young like mammals, which is a little unusual as reptiles are known to be oviparous (lay eggs), although it’s not uncommon. Preparation of the body towards pregnancy begins in autumn, through winter, until spring (Van Wyk 1994). This process of preparation is the divergence of important nutrients towards reproductive cells (Van Wyk 1994).

Nutrition and energy intake, especially before winter, seem to play an important part in the preparation of pregnancy (Edwards & Jones 2007). It is during hibernation (winter) that important biological and physiological changes occur in anticipation of mating, and ultimately pregnancy during spring (Gavaud 1983). Gestation periods in viviparous lizards, including Smaug giganteus, are usually long, up to two years (Fogel 2000). Smaug giganteus females give birth to between one and two young.

Family life

Smaug giganteus usually live in colonies of burrows with more than one individual per burrow. It was also observed in captivity that burrows are usually occupied by more than one individual (Fogel 2000). With female reproducing biennially or triennially, they are believed to put a lot of effort into taking care of their young. This means there is a lot of parenting from the female.

Giant girdled lizard - SANBI (3)

THE BIG PICTURE

Friends and Foes

Smaug giganteus, being the largest member of its group and one of the largest terrestrial lizards, especially in its restricted area, can be inferred as having little competition from other lizard species. Other species like frogs and birds may compete with it for food.

Smaug giganteus may be part of the food web as prey for other species groups, which can include birds of prey, larger reptiles like snakes, and some mammals such as jackals, foxes, honey badgers and mongoose.

Smart Strategies

The entire body of Smaug giganteus is covered in spiny scales. These serve as protection from its predators. They have also evolved not to wander too far from their burrows, which they quickly run to at any sign of disturbance. Their colour patterns match those of the grassland environment they occupy, which makes them blend in and be nvisible to their predators.

Poorer world without me

Smaug giganteus are insectivores, by eating insects they help control insect pests that may be problematic to the nearby crop fields. They are also prey to other animals.

People & I

Smaug giganteus are fascinating creatures. Their morphology and behaviour is captivating. The fact that their entire bodies are covered in thorny spines and that, when standing, they raise their head as if looking at the sun seems to fascinate a lot of people. So much so that it is thought J.R.R. Tolkien was inspired by Smaug giganteus when developing the character of ‘Smaug’ in the novel The Hobbit. Smaug giganteus has long been used in the muthi-market (traditional medicine) by Africans, mostly by the Basotho tribe (Parusnath 2014). Recently traditional healers of most tribes in South Africa used them. Parts of the lizards are ground into powder to make potions that are believed to allow men to have multiple partners without fuss from the wife or girlfriend (Parusnath 2014).

Fascination for Smaug giganteus is so great that it is in demand in the international pet trade. People and institutions around the world have imported these creatures from South Africa. They have an unusually high cost, but that doesn’t stop people from buying them.

Smaug giganteus has captivated people so much that recently there has been a petition launched by Dr Ian Little, who is a manager of the Threatened Grassland Species Programme of the Endangered Wildlife Trust. The petition is for Smaug giganteus to be made South Africa’s national lizard.

Giant girdled lizard - SANBI (4)

Conservation status and what the future holds

Smaug giganteus is classified as vulnerable under the IUCN Red Listing criteria (Bates et al. 2014). This is because the creature is under threat of habitat loss from agriculture and mining. It is also constantly being collected from the wild, because of the difficulty of captive breeding, for pet trade and muthi-markets. With such high habitat restriction, these activities threaten to drive these creatures to extinction.

There has been measure put into place to protect these creatures. They are internationally protected under CITES Appendix 2 and nationally protected through TOPS (Threatened or Protected Species). There is also research being done by different research institutions and NGOs on how to better protect and manage these species.

Relatives

Smaug giganteus belong to a genus of six species (Bates 2014). The species that bears the closest resemblance to Smaug giganteus in the same genus is Smaug breyeri and Smaug vandami. Ouroborus cataphractus, which is from a different genus, also looks similar. They all used to be contained under the same genus Cordylus.

Giant girdled lizard - SANBI (5)

Scientific classification

Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Cordylidae
Genus: Smaug
Species: S. giganteus, Smith, 1844.

References and further reading

  • Bates, M.F. 2014. Gerrhosauridae. In M.F. Bates, W.R. Branch, A.M. Bauer, M. Burger, J. Marais, G.J. Alexander & M.S. de Villers (Eds). Atlas and Red list of the reptiles of South Africa, Lesotho and Swaziland. Suricata 1. South African National Biodiversity Institute, Pretoria.
  • Cooper, W.E., Whiting, M.J. & Van Wyk, J.H. 1997. Foraging modes of cordyliform lizards. South African Journal of Zoology 32,1: 9–13.
  • Edwards, A., Jones, S.M. & Wapstra, E. 2002. Multiennial reproduction in females of a viviparous, temperate-zone skink, Tiliqua nigrolutea. Herpetologica 58,4: 407–414.
  • EWT. 2013. Sungazer. http://www.ewt.org.za/species%20factsheets/Sungazer.pdf. [accessed 13 March 2014].
  • Fogel, G. 2000. Observations on the giant sungazer lizard, Cordylus giganteus, in Captivity. Bulletin Chicago Herpetological Society 35,12: 277–280.
  • Frost, D., Janies, D., Mouton, P. le F.N. & Titus, T. 2001. A molecular perspective on the phylogeny of the girdled lizards (Cordylidae, Squamata). American Museum of Natural History 3310: 10.
  • Gavaud, J. 1983. Obligatory hibernation for completion of vitellogenesis in the lizard Lacerta vivipara J. Journal of Experimental Zoology 225: 397–405.
  • Gibbons, B. 2014. Sungazer lizards are desperately in need of conservation. https://www.ewt.org.za/newsletter%20articals/SungazerBG_final.pdf. [accessed 2 May 2014].
  • Losos, J.B., Mouton, P. le F.N., Bickel, R., Cornelius, I. & Ruddock, L. 2002. The effect of body armature on escape behaviour in cordylid lizards. Animal Behaviour 64: 313–321.
  • Louw, S., Burger, B.V., Le Roux, M. and Van Wyk, J.H. 2007. Lizard epidermal gland secretions1: chemical characterization of the femoral gland secretion of the sungazer, Cordylus giganteus. Journal of Chemical Ecology 33: 1806–1818.
  • McIntyre, T. 2006. Impact of gold mining on Cordylus giganteus and recommendations for conservation and management. MSc Dissertation, University of the Witwatersrand, Johannesburg, South Africa.
  • Parusnath, S. 2014. A conservation assessment of the sungazer (Smaug giganteus). MSc Dissertation, University of the Witwatersrand, Johannesburg, South Africa.
  • Van Wyk, J.H. 1991. Biennial reproduction in the female viviparous lizard Cordylus giganteus. Amphibia-Reptilia 12: 329–342.
  • Van Wyk, J.H. 1994. Physiological changes during the female reproductive cycle of the viviparous lizard Cordylus giganteus (Sauria: Cordylidae). Herpetologica 50,4: 480-493.
  • Van Wyk, J.H. 2000. Seasonal variation in stomach contents and diet composition in the large girdled lizard, Cordylus giganteus (Reptilia: Cordylidae) in the Highveld grasslands of the northeastern Free State, South Africa. African Zoology 35,1: 9–27.

Author: Mahlatse Kgatla
SANBI Biosystematics
November 2014

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