Search

Snakes are ecologically and morphologically plastic organisms that exhibit extensive variations in body size and body condition in response to environmental factors. Documenting inter-population variations is important to describe species comprehensively across their distribution range and to monitor trends over time (e.g. decreasing body condition due to alteration of habitat). Thus, we analyzed the influence of population and sex on body size and body condition in three populations of nose-horned vipers (Vipera ammodytes) in Serbia. In one population, males were larger than females (F1, 39=4.802, p=0.034), but not in the two other populations (F1, 36=0.075, p=0.786; F1, 21=0.018, p=0.893). Females exhibited higher body condition (residual values from the regression of log-body mass against log-body size) than males (F1, 90=10.444, p=0.002); this sex difference was not found in one population when analyzed separately (F1, 35=1.834, p=0.184). Moreover, we found strong inter-population differences in mean body size and mean body condition (F2, 96=8.822, pF2, 90=10.319, p=0.001, respectively). While inter-population difference in body size was driven by males, inter-population difference in body condition was driven by females. These results suggest that, in this species, body size might be an important determinant of mating success in males, while body condition may play a major role in female fecundity.

Different snake species may be active at various times of the day. In Europe, most snake species are predominantly diurnal, but about a third are partially or principally crepuscular and/or nocturnal. Here, we report the first instance of multiplein situobservations of the crepuscular and nocturnal activity ofV. ammodytesin Bulgaria. Overall, usually as a result of general herpetological surveys and chance observations between 2001–2020, we recorded crepuscular/nocturnal activity of twenty-seven individuals from both sexes and all age classes (juvenile to adult), observed from April to September, following warm (maximum daily Tair= 20–28 °C) and hot (Tair> 28 °C) days. These records represent less than 1.5% of all our personal viper observations. However, given that our observations occurred throughout the country, within five different climatic zones, we hypothesise that nocturnal activity ofV. ammodytesis more common than previously reported.