An Introduction to the Family Varanidae

There are two explanations of the origin of the common name "monitor lizard", The Oxford English Dictionary attributes it to the belief that they gave warning of the vicinity of crocodiles. A more likely explanation is that the Arabic term for a lizard "ouaran" became l:onfused with the German verb "Warane" (to warn), hence the scientific name Varanus and the English term monitor (Lydekker in Stirling 1912). In parts of the world colonised by Europeans the monitors were confused with the large lizards of the Americas, the iguanas. Hence in Australia they are known as goannas. and in South Africa they are known as leguaans.

Easy identification of monitors is hampered by two things; dramatic differences in the appearance of young vs. adults and geographical variations in colour and morphology, particularly in species which inhabit a wide range. Scientists often rely heavily on scale counts and characteristics to distinguish species. Unfortunately it is utterly impractical to count the scales of animals seen only at a distance, or those of captives, particularly of the very large and very small varieties. I have avoided detailing the scalation of the monitors except where no other characteristics will serve to distinguish species or subspecies. This information can be found in the literature cited. Keys to distinguish monitor species can be found in various works of Mertens (translations in Funk and Vilario 1980), Storr (1980, et al 1983) and Vernet ( 1984).

Difficult to spell and impossible to pronounce, scientific names are cumbersome and tonguetwisting, but essential. Even today much information in the literature is wasted or misunderstood because of confusion over the identity of the creatures concerned. Scientific names are used as little as possible here, but their use is vital for correct identification of different species because common names (e.g. "water monitor") are often ambiguous.

Monitor lizards belong to the family Varanidae. At present all living species belong to the genus Varanus and all other recognised genera are considered extinct. The generic narne Varanus is often abbreviated to V. and the specific name written in its entirety, e.g. V.tristis. Between the generic name and the specific names a subgeneric narne may be inserted in brackets, e.g. Varanus (Odatria) tristis. After the specific name there may be a subspecific name, e.g. Varanus (Odatria) tristis orientalis. In some cases the subspecific name may eventually replace the specific name if the animals are thought different enough to warrant being recognised as separate species, e.g. Varanus (Odotria) orientalis. It is possible that the genus Varanus will be split into a number of smaller genera before the end of the century, because some people consider the present classification to be too simple. In this case the subgeneric name may replace the generic name, e.g. Odatria tristis orientalis or even Odatria orientalis. The name is followed by the author and date of the animals' original description, in which he or she nominated a single, pickled, lizard as a typical example of the race. This unfortunate creature is known as the holotype. In the past many people have named animals without being aware of previous descriptions of the same species. In this case the name of the oldest existing holotype is given priority. Many monitor lizards have been renamed. or even unnamed, in recent years. In addition many monitor species remain undescribed. A useful list of poorly-known monitors and unknown species can be found in Philippen (1995).

Where scientific names are completely useless is in the areas where the lizards actually live. For example, a monitor lizard from Africa is known as eikwambo, mbulu, gruza, awonriwan, kgwate, uxamu, mampan-tintin and at least a hundred other names, but very few of the people who are acquainted with it in nature are aware of Linnaeus' description of the species in 1758 and the subsequent revisions that led to the name Varanus niloticus. This is unfortunate for us, for they are the people who know most about it and can contribute best to our knowledge of its natural history. Much can be learned about the ecology of monitor Lizards even on a family holiday, by questioning knowledgeable locals. Knowing the local name for the animal you are interested in and having a good clear photograph of it are essential to avoid misunderstandings. They will probably be happy to show you the animals living wild and give you the most memorable moments of your holiday. As our understanding grows, so does our respect for those with whom we share the planet.,; who were here long before us and may be here long after.

Attribution / Courtesy: Daniel Bennett. 1995. A Little Book of Monitor Lizards. Viper Press U.K.