Keeping and Caring for Monitor Lizards and Tegus

Keeping and Caring for Monitor Lizards and Tegus

by Lenny Flank

© Copyright 2009 by Lenny Flank

All rights reserved

Smashwords ebook edition.

Red and Black Publishers, PO Box 7542, St Petersburg, Florida, 33734

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Contents

Monitor Lizards

One: Choosing a Monitor Lizard

Two: Housing

Three: Feeding

Four: Handling and Taming

Five: Diseases and Health Problems

Six: Breeding

Tegu Lizards

One: Choosing a Tegu

Two: Housing

Three: Feeding

Four: Handling and Taming

Five: Diseases and Health Problems

Six: Breeding

Monitor Lizards

One: Choosing a Monitor Lizard

Are you an experienced reptile keeper looking for an interesting, intelligent, colorful and active lizard to add to your collection? If so, then one of the monitors may be for you.

There are around 40 species of monitors, all of which are large and active predators belonging to the varanid family of lizards. They fill a number of environmental niches, from the green tree monitor, which is largely arboreal and feeds on insects and small animals, to the Komodo dragon, a terrestrial predator which is at the top of its food chain and can feed on animals as large as goats and water buffalo. As a group, varanids are found in Africa, Asia and Australia. None are found in the New World.

The monitors are all members of the genus Varanus. The genus name comes from the Arabic word al waran, which refers to the Nile monitor, one of the most widely distributed members of the group. Over half of the members of the monitor family live in the dry arid regions of Australia, where they are known as goannas, a corruption of the word iguana.

The monitors vary greatly in size. The dwarf monitors, such as the green tree monitor and the Timor monitor, reach lengths of one and a half to two feet (some of the small Australian goannas barely reach a foot in length). The giant monitors include some of the largest living reptiles. The common Nile monitor can reach six and a half or seven feet in length, and the crocodile monitor exceeds nine feet in length. The largest living lizard, the Komodo dragon, reaches ten feet in length. It is a member of the monitor family.

The savannah monitor, from Africa, is by far the most common predatory lizard in the pet trade, and is very widely available. A number of other species are also becoming more widely available. Unfortunately, a number of keepers obtain these lizards when they are young, without any real idea of what they are getting into. Although young monitors can be tamed, they are potentially aggressive animals which can sometimes be difficult to handle safely. None of these lizards are suitable for beginning reptile-keepers. However, if kept in a responsible manner by an experienced reptile hobbyist who shows proper respect for these magnificent animals, monitor lizards can make fascinating and responsive pets.

Here are some things to consider before you bring home a monitor. These lizards are very powerful, and many species get very large. They have strong jaws filled with over 200 razor-sharp teeth, and even small individuals can give nasty bites. Their claws are recurved and powerful, and can rip gaping wounds in your skin. An encounter with an angry or frightened adult monitor can easily result in a trip to the hospital for stitches. In addition, they can use their tails as a whip to inflict painful welts on the unwary. These are not lizards for beginners.

Monitors grow quickly. The cute little hatchling you buy today will, in just a few years, be transformed into a five or six foot lizard that can live for over fifteen years. Within a short time, your large monitor lizard will need almost as much living space as you do. Before you obtain a large predatory lizard, be sure that you will be able to provide it with all of its specialized needs throughout its life.

On the positive side, there are a number of traits which make these huge lizards attractive as pets. Monitors are extremely intelligent for reptiles. They are active and alert, and unlike many other reptiles, can become very responsive towards their keeper. Some species of monitors can become very docile and seem to enjoy being handled and petted. The savannah monitor and the water monitor are particularly apt to become puppy-dog tame. This trait, combined with the natural curiosity and inquisitiveness of these lizards, makes them endearing and responsive pets.

Monitors lizards belong to the reptile suborder Sauria, part of the order Squamata which includes the snakes. There are about 3,000 species of lizards living today. The monitor lizards belong to the family Varanidae, which contains around 40 members.

The taxonomic status of monitor lizards is confused not only by the lack of study among these groups and a consequent scarcity of data on which to base a conclusion, but also because the very basis of taxonomy—the science of classifying organisms—is now being questioned by a significant number of biologists. The basic unit of taxonomy is the species, which is defined as a population of organisms which are capable of interbreeding and producing fertile young, thus exchanging genetic information with each other.

A number of species that are related to each other through evolutionary descent and common anatomy are grouped together in a genus (the plural is genera). A group of related genera are classified together as a family. All of the monitors discussed in this book belong to the genus Varanus (which contains all of the living monitor species). This genus is in turn placed in the family Varanidae, which contains all of the monitors plus their living and extinct relatives (lizards of the Panthanotus genus have recently been placed in this family too).

In many species, however, there exist populations, usually at the edges of their range, which differ in recognizable ways from the main population but which are still capable of interbreeding with the rest of the species. In traditional taxonomy, these distinct populations are referred to as separate races or subspecies, and evolutionary theory concludes that these subspecies are in the process of evolving in a different direction and becoming new full-fledged species, and thus should be granted a taxonomic distinction to recognize this fact. There are, for instance, several recognized subspecies of the water monitor, including the varieties V. salvator salvator, V. salvator marmoratus, and V. salvator cumingi.

Recently, though, a growing group of taxonomists known as cladists have questioned the validity of this concept, and have argued that the species is the only naturally existing grouping of biological organisms—all other categories are artificial and at least partially subjective. In particular, cladists argue that the only real evolutionary change in a species happens at a branching point where it becomes a distinct new species, and that therefore the entire subspecies concept, which holds that these populations are a sort of almost-species, is invalid. These taxonomists therefore argue that all existing subspecies are actually either separate and distinct species in their own right or should be classed with the existing species and not given their own subspecific name. In the cladist scheme, for instance, the various races of the water monitor would either be classed as new species (Varanus mamoratus or Varanus cumingi) or as simply members of the species Varanus salvator.

This change in thinking will undoubtedly have an effect on the hobby of reptile keeping. Certainly it appears that a number of currently recognized subspecies, including several races of such wide-ranging species as the water monitor, mangrove monitor and Gould’s monitor, are actually separate and distinct species. (The white throated monitor was once considered a subspecies of the savannah monitor, but is now classed and bred as a separate species.) Such a distinction is important if these animals are to be captive bred, and may also turn out to be significant in terms of habitat requirement and captive husbandry. A tremendous amount of field work is needed to determine if these subspecies are actually members of separate species, with distinct breeding and environmental requirements of their own, or