Arboreal mating by rough-necked monitors Varanus rudicollis in Sabah, Malaysia 💕

🦎 The Roughneck monitor, Varanus rudicollis (Gray, 1845), is a large (TL 146 cm), arboreal species, although there are some reports of it being ground-dwelling. It is diurnal and native to primary and secondary rainforests in Myanmar, Thailand, Malaysia, and the islands of Penang, Sumatra, Riau, Bangka, and Borneo. Despite this wide range, it is one of the most poorly studied varanid species, as direct observations in the wild are very rare, especially as it prefers to shelter in tree hollows in dense jungle.

🕵‍♀️ The conservation status of Varanus rudicollis in the IUCN Red List of Threatened Species is Data Deficient, indicating a lack of information about this species.

📣 A newly published note presents the first documented, direct observations of mating in this species from northern Borneo.

👀 The only details about the reproduction of this species come from captivity: clutches consist of 8–16 eggs (up to 3 clutches per year), approximately 4 weeks after mating, the incubation period is 152–190 days at 28–30°C, hatchlings measure 200–260 mm, and weigh 14–21.6 g.

🦉 Observations such as these, even as single events, broaden our understanding of the natural history, mating period, and behaviour of this difficult-to-observe monitor lizard species.

More information:

👉https://www.researchgate.net/publication/398181153_Arboreal_mating_by_rough-necked_monitors_Varanus_rudicollis_in_Sabah_Malaysia

ZDUNEK, P., DOMAGAŁA, M., TAKÁTS, B. (2025). Arboreal mating by rough-necked monitors Varanus rudicollis in Sabah, Malaysia. Herpetological Bulletin 174: 42-43.

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