VARANUS (MONITOR LIZARD)

Contents hide

1) Introduction

2) Classification of Varanus (Monitor Lizard)

3) Geographical distribution

4) Habit and habitat

5) General Characteristics of Varanus (Monitor Lizard)

6) Ecological Importance

7) Conservation Status

8) Special features

9) Identification

Introduction

The genus Varanus encompasses a wide range of monitor lizards, known for their intelligence, agility, and adaptability. These reptiles are found across Africa, Asia, and Australia, inhabiting diverse ecosystems such as forests, deserts, and wetlands. Species like the Komodo dragon (Varanus komodoensis) and the water monitor (Varanus salvator) are iconic representatives of this group.

Classification of Varanus (Monitor Lizard)

Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
Group :- Craniata (Definite head, Cranium with brain present.)
Sub phylum :- Vertebrata (Vertebral column present.)
Division :- Gnathostomata (Jaws and paired appendages present.)
Super Class :- Tetrapoda (Paired limbs, lungs, cornified skin and bony skeleton.)
Class :- Reptilia (Scaly vertebrates. Right and left aortic arches present. Single condyle. Pulmonary respiration. Embryo with amnion and allantois.)
Sub Class :- Diapsida (Skull with two temporal openings separated by post-orbital and squamosal.)
Order :- Squamata (Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse.. Vertebrae amphicentrous.)
Sub-order :- Iguania (Lizards. Body slender, limbs 4. Pterygoid in contact with quadrate. Eyelids movable.)
Family :- Varanidae (Large trunk. Limbs stout. Tongue bifid.)
Genus :- Varanus

Geographical distribution

Varanus is distributed in Africa, Southern Asia, South East islands of Australia, India, Sri Lanka and Malaya. Old world lizard.

Habit and habitat

Varanus inhabits dry places under stones and rocks and leads a burrowing life. It is most active at night and feeds upon tortoises, squirrels and dead bodies of other animals. Monitor lizards are carnivorous and semiaquatic.

General Characteristics of Varanus (Monitor Lizard)

Commonly known as Monitor lizard.
Animal measuring 60 to 90 cm in length is divided into head, neck, trunk and tail.
Body is covered with smooth, small scales having large brownish, black and orange patches, which act like warning colours.
Head is triangular and contains fixed eyes, nostrils and mouth. External ear opening present just behind head.
Mouth gap wide with a long bifid smooth and protrusible tongue. Teeth large pointed, pleurodont and dilated at base.
Osteoderms absent. Post-orbital arch incomplete.
Trunk is large and stout. Tail is long thickened and serves as storehouse for fat.
Forelimbs and hind limbs are stout, well developed and adapted for swift movement, but they can hardly lift the body up from the ground. Digits are clawed.

Ecological Importance

Top Predators:
- Monitor lizards are apex or mesopredators in their ecosystems, feeding on insects, small mammals, birds, and carrion.
- They help regulate prey populations, ensuring ecological balance.
Seed Dispersers: Some monitor lizards consume fruits, aiding in seed dispersal and contributing to forest regeneration.
Scavengers: By consuming carrion, they play a role in nutrient recycling and preventing the spread of disease.
Indicators of Ecosystem Health: Their presence and population trends reflect the health of their habitats, making them important bioindicators.

Conservation Status

Varied Status Among Species:
- Varanus komodoensis (Komodo Dragon): Vulnerable.
- Varanus salvator (Water Monitor): Least Concern, though facing threats in localized areas.
- Varanus mabitang (Philippine Mabitang): Endangered.

Threats:
- Habitat loss due to deforestation and urbanization.
- Illegal hunting and poaching for skin, meat, and the pet trade.
- Climate change impacting their natural habitats.
Conservation Measures:
- Protected areas and national parks, such as Komodo National Park for the Komodo dragon.
- Legal protections under CITES, restricting international trade of endangered species.
- Community-based conservation initiatives in local habitats.

Special features

Intelligence: Monitor lizards exhibit advanced problem-solving abilities and can learn from experience, making them among the most intelligent reptiles.
Adaptability: They thrive in diverse habitats, from arid deserts to mangroves and forests.
Forked Tongue: Similar to snakes, their forked tongues help them detect scents and locate prey.
Efficient Hunters: Equipped with sharp claws, strong limbs, and powerful jaws, they are skilled hunters capable of taking down a wide range of prey.
Thermoregulation: Monitor lizards are ectothermic, relying on basking in the sun to regulate their body temperature.
Size Diversity: The genus ranges from the small Timor monitor (Varanus timorensis), measuring about 20 cm, to the massive Komodo dragon, which can grow up to 3 meters long.