Habitat-linked morphological variation in the Asian water monitor lizard (<em>Varanus salvator</em>) across urban, agricultural, and forest landscapes in peninsular Malaysia
DOI:
https://doi.org/10.11160/bah.306Keywords:
Asian water monitor lizard, disturbance, habitat, morphology, varanidsAbstract
The Asian water monitor lizard, Varanus salvator is a widespread carnivorous reptile in Malaysia, yet the effects of habitat disturbance on its morphology remain poorly understood. This study examined 168 individuals from urban, agricultural, and forest habitats using morphometric measurements of snout–vent length (SVL), weight, skull length, thigh width, and body condition. To assess shape-level differences independent of body size, size-corrected traits were calculated as residuals from log–log regressions against SVL. Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), and one-way MANOVA were used to evaluate morphological divergence among habitats. Results showed that morphological variation was structured primarily by habitat type rather than site-specific effects. SVL did not differ significantly across habitats, indicating similar growth potential across the disturbance gradient. However, urban lizards exhibited consistently larger relative traits, and better body condition than those from agricultural habitats, with forest individuals showing mixed patterns but closer to agricultural lizards. Lizards from agricultural habitats had the narrowest thighs and poorest condition, potentially a result of habitat specific stressors. These findings suggest that habitat type influences energy allocation to structural and performance-related traits, rather than limiting size. While V. salvator appears morphologically adaptable to anthropogenic environments, future studies incorporating sex, diet, and predator interactions are needed to clarify the drivers of trait variation and assess potential fitness consequences in disturbed landscapes.
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