Saturday, 4 April 2015

Lizards 6: Round-Nosed Plated Lizard

Gerrhosaurus major
Of the larger lizards in the Bristol Zoo collection, one of the more distinctive is the Round-Nosed Plated Lizard, Gerrhosaurus major. Also called the Sudan Plated Lizard, Western Plated Lizard, Rough-scaled Plated Lizard, and other names as well, it has a large range across most of eastern and southern Africa. 

There are several other species of plated lizard, and a recent genetic analysis of the group revised the classification of the various clades considerably, splitting G.major into a new genus Broadleysaurus. Other related species are the various species of Zonosaurus from Madagascar and the Seychelles, and more distantly the girdled lizards Cordylus from rocky habitats across Africa.

Physically, plated lizards are large, heavy bodied lizards with short legs for their size and a tail about the same length as the body if not shed and regrown (which happens frequently). The body length is around 30cm, and the scales are underlain with osteoderms, bony plated which provide some protection from predators.

In behaviour all the plated lizards are quite similar. They are day active lizards, foraging among the grasses and rocks which are their typical habitat for various insects and other invertebrates, with large individuals potentially taking small vertebrates like smaller lizards or nestling rodents.. They will also take some plant material, but given how seasonal the rainfall is in their environment probably only at certain times of the year. They are extremely quick, and rapidly dive for cover if threatened. When not foraging, they conceal themselves in a burrow dug in the ground.

Plated lizards are oviparous, producing small clutches of 2-4 eggs which are buried in the ground. Incubation is around 90-120 days and the young are independent from hatching. Lifespan in captivity is up to 15 years or so.

In captivity, plated lizards quickly become tame and responsive to their carers. Unfortunately, just about all the captive animals in the pet trade are wild caught, as their low reproductive rate makes it difficult to produce them commercially in the same way as, say, bearded dragons. For this reason I could not recommend them as a suitable pet reptile unless the situation changes and breeders start producing them in captivity. The wild population is not currently listed as threatened, but some of the plated lizard species have quite limited ranges and are potentially vulnerable to habitat alteration as a result of changes in agricultural practise such as overgrazing.

(image my own)

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