Background: the anatomy and physiology of bovid horns are consistent with their thermoregulatory function. Objective: to evaluate a possible correlation between ear and horn size, as key factors for body thermoregulation. Methods: measurements of horns (length and perimeter) and ears (length and width) were obtained from forty-six Pyrenean Brown (Bruna dels Pirineus) beef calves. The sample was randomly distributed between horned (n=34) and polled (n=12) animals, aged 332 ± 56 days. Results: a negative correlation between ear and horn size was observed (p<0.05) and the multivariate clustering demonstrated a tendency of polled animals towards bigger ear size. Conclusions: according to these results, horns and ears contribute to thermoregulation; this function is not therefore solely a function of big or small horns, as has normally been stated to be the case. Although the sample is small, results would indicate an interesting hypothesis for future research.