Robert Sprackland's Herpetology World

Varanid Biology, or a Monitor Monograph

MONITOR LIZARDS. Varanids. Goannas. For over 40 years these remarkable lizards have held my unwavering attention, leading me to examine thousands of lizards in museums, zoos, at universities, in the field, in private collections... and possibly places I just can no longer remember. When I began my studies there were rather few herpetologists interested in monitors as research subjects. There was, as I recall, only one book dedicated to monitors, from 1963, and several technical papers, but not much else. Today, however, I have lost count of the number of books, and dare not contemplate how many papers and articles, have appeared since then. I have also learned that as of now--late 2019--there are at least three independent research groups once more delving into the realm of varanid systematics.

So what am I doing now? With all those notes and reams of data going back to just a few years after Neil Armstrong first set foot on the moon, I am collating and editing all those notebooks of information. To my surprise, given the amount that has been published since then, I am still able to offer a great deal of untrod turf. In my presentation of the story of monitor lizards, I start with their prehistoric past, review their evolutionary and zoogeographical history, and look at their current diversity. This is NOT a book about each species, a catalogue similar to those that have come earlier; rather, this is a tale about variation, both subtle and discrete, throughout a group so reliably--and to my mind, incorrectly--described as conservative. There is a great deal more to the variations among the myriad of monitors than the huge range of size among species, or colouration. Darwin would have loved these creatures, had he a bit less botanical leanings, for they present a marvelous case of a physical story of where variation goes, how much a phenotype can experiment before hitting a wall or developing a new species. 

From time to time I shall post updates of my progress. As of today I have written drafts of a few sections in order to help me flesh out the outline (which is about 11 pages long). Mostly, I have written a few dozen pages about a few cranial bones, but there is still much more to add on those before I tackle the others. There will be an early chapter tracing the history of varanid research, featuring the major contributors to that work from antiquity to the present. And yes, this book is about the entirety of the Varanidae, so the fossil taxa will be covered as thoroughly as their remains allow.

If this is your first visit to my Herpetology World, I'd like you to know that I have uploaded several of my reprints on my  DOCUMENTS  page. There is also a more extensive offering of my papers at, and they are all free. So download, read, enjoy. 

Also, I invite you to read some of my articles on Hub Pages ( 

Erpétologie générale, ou, Histoire naturelle complète des reptiles (1834-1854), by

A.-M.-C. Duméril and  G. Bibron

The complete 9 volumes bound in 5 of text (almost 7000 pages), plus an atlas of 120 plates.$275.00 (USD).

Among the published works in herpetology over the last five centuries, only two can be said to cover all known species of amphibians and reptiles comprehensively and scientifically. One of these, in French, was by produced by Constant Dumeril, Gabriel Bibron, and the senior author's son, Auguste Dumril, and based on the collections of the Museum d'Histoire Naturelle in Paris. This classic work remains of continuing value to a broad community of academic zoologists, museum and zoo curators, and conservationists, and especially to herpetologists working in developing countries.  This full-size facsimile is absolutely complete and carefully edited for clarity. The nine text volumes, which total about 7,000 pages, and atlas of 120 plates are sturdily bound in library-grade red cloth and printed on durable, acid-free paper. A new introduction by Roger Bour (Paris) is an in-depth review of the book (including exact publication dates) with new biographies of the three authors. A comprehensive index to the scientific names, missing in the original book, has been added.