The Herpetological Journal

Authors: Patricia Marques do A. Oliveira, Carlos A. Navas & Pedro M. Sales Nunes

Abstract: Semi-arid environments impose significant thermal stress on ectotherms, requiring specialised water acquisition strategies. This study investigated the water status of three lizard species from the Caatinga, examining the interaction between environmental factors and physiological adaptations for water acquisition. To achieve this, we combined field data—including body mass, body condition and body temperature—with induced hydration experiments to quantify water uptake. Additionally, environmental factors such as soil and air temperature, as well as humidity, were measured. Ameivula ocellifera exhibited the highest water absorption, potentially reflecting greater dehydration due to its active foraging and sun exposure. Conversely, Tropidurus semitaeniatus absorbed less water, suggesting better hydration, possibly linked to its rocky habitat that may enhance water retention. Soil temperature and humidity significantly influenced the water status of all species, underscoring the role of ectothermy in water regulation. These findings highlight the importance of ecological context and environmental conditions in shaping water-related adaptations in semi-arid lizards.

Keywords: reptiles, brazilian drylands, experimental hydration, body weight