Our latest research explores how the nutritional composition and physical traits of Mediterranean plants influence the feeding preferences of red deer (Cervus elaphus), combining controlled cafeteria experiments with field observations to better understand herbivore diet selection. We found that deer clearly prefer species such as Quercus ilex and Cistus albidus, while consistently avoiding plants like Rosmarinus officinalis and Thymus vulgaris, with these patterns matching natural browsing behaviour in the field. Importantly, our results show that chemical traits—particularly protein, fibre, and mineral content—play a much stronger role than physical resistance in shaping feeding choices, highlighting that deer prioritise nutritional quality over plant toughness. These findings provide valuable insights into plant–herbivore interactions in Mediterranean ecosystems and offer practical implications for wildlife management, especially in areas where increasing deer populations may significantly impact vegetation dynamics and biodiversity.