07 April 2013

Desert (Grey) Monitor – Tabuk record by Viv Wilson

Viv Wilson kindly sent me some more of his excellent photos taken in the Tabuk area of Saudi Arabia. He has also kindly allowed me to use some on my website, shown below. Copyright remains with Viv.

The Desert Monitor Varanus griseus, is a species of monitor lizard with three subspecies, the one occurring in Saudi Arabia being Varanus griseus griseus also called the Grey Monitor. This subspecies is found from Northern Africa throughout the Sahara, Arabian Peninsula and southwestern Asia eastwards to northwestern India. It has 5-8 narrow grey bands on the back as well as 19-28 bands on the tail, the highest number of bands of any subspecies. Its tail is more rounded that those of the other subspecies and the final size of the adults average around one to 1.3 mtres in length (approximately 55–65 cm excluding their tail) with their overall body size dependent on the available food supply, the time of year, environmental climate, and reproductive state, with males generally larger than females. The body is long and robust, with sturdy limbs, and a long, powerful tail which can be used liked a whip in defence as they are aggressive reptiles. The nostrils of this species are particularly distinctive, comprising diagonal slits much closer to the eye than the tip of the snout. Their coloration can be a simple grey if living in desert-like ecosystems, to more brilliantly colored if living in areas with large amounts of plant growth. It is a carnivorous lizard that feeds on a wide range of vertebrates and invertebrates with the most common prey consisting of lizards and snakes, but can also include ground-nesting birds and other small mammals. They hibernate from September to April becoming most active between the months of May and July. They are active during the day, emerging from their burrows in the early morning, and basking in the sun at the entrance in order to raise their body temperature often staying in their burrows during the heat of the day. During a single day, Desert Monitors range over large distances, usually between five and six kilometres, returning to their burrow before sunset. They are predominantly desert-dwelling, although can occupy a variety of arid and semi-arid habitats with a specific habitat requirement being the presence of sand or soft soil in which tracks can be made for communication and orientation. Their skin is adapted to the desert environment in which they live, and they are excellent swimmers sometimes entering water to hunt for food and have a lifespan of approximately eight years.