Identification:
The Asian Water Monitor (Varanus salvator) can reach up to 2.5 meters in length, with females typically smaller. It is the largest lizard species in the Varanidae family found in Vietnam. They have a long, tapered head, a long neck, and a long, slightly flattened snout. The nostrils are oval-shaped, positioned closer to the snout than the eyes. The tongue is long and slender, deeply forked at the tip, and constantly protrudes and retracts from the mouth like a snake’s tongue. The body is long and robust, with a laterally compressed tail and a prominent dorsal ridge. Juveniles have a black back with small to large, circular yellow spots arranged in rows. There are distinct horizontal stripes on the labial scales. A dark stripe extends from the eye to the temporal region. Adults have a brownish-yellowish-green coloration. The patterns on juveniles become less distinct and harder to differentiate in older individuals.
Biology and Ecology:
Asian Water Monitors typically inhabit the banks of rivers, streams in midland and mountainous regions, and mangrove forests in coastal areas. They hide in crevices, under tree roots, or in thickets. They are excellent swimmers and divers, capable of remaining submerged for 20-30 minutes. They are omnivorous, feeding on a variety of animals: crabs, frogs, toads, and fish are preferred prey. They also consume eggs, young birds, small mammals, other lizards, and large insects. Juveniles primarily eat insects.
They usually hunt during the day, searching in river and stream banks, shallow water environments, and in thickets. They hunt by ambushing and pouncing on prey. They use their forked tongue to detect prey by scent. If the prey is too large, they use their teeth and forelimbs to tear it apart. During the midday heat, they often hide in burrows, under bushes near water, or immerse themselves in water. They become active in the late afternoon until dusk, then return to their burrows for the night.
They lay eggs in the summer, from April to May to July to August, depositing approximately 15-20 eggs in burrows along riverbanks or in thickets near water. The eggs are off-white, tapered at both ends, and about 5 cm long.
Distribution:
In Vietnam: Cao Bằng, Lào Cai, Lai Châu, Bắc Kạn, Lạng Sơn, Sơn La, Vĩnh Phúc, Hòa Bình, Bắc Giang, Quảng Ninh, Hải Dương, Hà Tây, Phú Thọ, Ninh Bình, Thanh Hóa, Nghệ An, Hà Tĩnh, Thừa Thiên – Huế, Quảng Nam, Gia Lai, Kontum, Đồng Nai, Đắk Lắk, Lâm Đồng, Bình Phước, Bình Thuận, Bạc Liêu, Bà Rịa – Vũng Tàu, Cà Mau.
Worldwide: India, Sri Lanka, Bangladesh, southern China, Myanmar, Laos, Thailand, Cambodia, Malaysia, Singapore, Indonesia, Philippines.
Value:
Asian Water Monitors are large, have attractive skin, and are docile. They are valued for their aesthetic qualities and are kept in zoos. If permitted for commercial breeding in farms for propagation and skin harvesting, they could be used to create high-value handicrafts.
Conservation Status:
Populations have declined by at least 50% in the past and present, along with a decline in habitat quantity and quality due to environmental exploitation, especially poaching and illegal trade.
Classification: Endangered (EN A1c,d)
Conservation Measures:
Listed in the supplementary list of rare forest plants and animals (Decree 18-HDBT) Group II B. To protect the species, it is necessary to strictly prohibit hunting and illegal trade. Conservation efforts should include captive breeding programs in natural reserves.