Viper Gecko

Geographical Origin and Habitat: An extraordinary species endemic to the harsh desert and semi-desert regions of southern Asia, particularly in south-central Pakistan (Sindh province, along the edges of dry, dusty riverbeds). This strictly terrestrial gecko hides among dry sand and gravel, and may hiss when alert in the cool desert night.

Taxonomy and Genetics: A tiny gecko reaching a maximum adult length of about 8 cm. Previously classified under a separate genus (*Teratolepis*), it is now placed within *Hemidactylus* despite its unique appearance. It features large, heavily keeled and overlapping scales resembling shingles, which protect it from sharp stones and arachnid predators. The head is large, triangular, and viper-like, while the tail is thick and carrot-shaped, serving as a reservoir for fat and water storage. Coloration ranges from dusty taupe to steel grey with light crossbands or X-shaped markings on the back.

Behavior and Habits: A fascinating, nocturnal terrestrial reptile. They move raised on thin, stiff legs with a somewhat mechanical, robot-like walk. They hunt small insects at night and can jump short distances like springs. When threatened, they raise their heads to mimic the strike posture of a viper, and wave their thick, rough tail to distract predators away from their head.

Morphology: Sexual dimorphism is distinct in adults. Males are generally slightly bulkier and develop very prominent hemipenal bulges at the base of the tail and preanal pores, whereas females have a slimmer tail base and lack these features. Females also lay clutches of hard-shelled eggs frequently during the breeding season.

Terrarium Setup: A small horizontal terrarium (e.g. 45x30x30 cm) is fully adequate for a single individual or a small group. Use a dry sand-clay substrate (such as compacted desert bedding or stone desert) that allows burrowing and remains stable. Provide narrow, low-profile horizontal hiding places under securely placed rocks or cork bark.

Lighting and Heating: Hot, arid conditions are required. Provide a basking zone with a surface temperature of 35-37°C using a low-wattage halogen bulb or deep heat projector, and a cool end around 24-26°C. At night, the temperature should drop significantly to 20-22°C (or around 18°C in winter for pre-brumation). A low-level UVB light (2-5%) is highly recommended.

Humidity and Hydration: They require dry, well-ventilated conditions with ambient humidity around 30-40%. Lightly mist one corner of the enclosure or the side of the glass every few days to allow them to lick water droplets. Avoid damp substrates or high humidity, which can lead to skin infections and respiratory diseases.

Feeding and Supplementation: Active insectivores with a fast metabolism. Feed them small, live insects such as pinhead crickets, small roaches (*Shelfordella lateralis*), and small mealworms in a smooth bowl to prevent substrate ingestion. Dust their food with pure calcium twice a week, and regularly use calcium with D3 and multivitamins, especially for breeding females.

Compatibility: Strictly solitary. Males are highly territorial and will fight aggressively, often resulting in death. While females can sometimes be housed together in very large enclosures, keeping them individually is the safest practice to prevent stress and injury.

Health and Common Diseases: The tail is a primary indicator of health; a thin, shriveled tail indicates dehydration, parasite overload, or malnutrition. Avoid keeping them on loose damp substrate, which can cause impaction if ingested, or shell rot. Due to their tiny size (3-6 grams), they are fragile and veterinary care can be difficult.