Observations from the 2019 Red Deer Rut As summer draws to a close, and the nights draw in, the temperatures begin to drop, and the leaves start to change colour. Autumn is upon us, and so brings this years Red Deer Rut. Physiology Red Deer ( Cervus elaphus ) is Britain's largest native land mammal, with the male Stags reaching 1.2 meters (48 inches) high at the shoulder, and up to 240kg's (530 lb) in weight. From around 10 months old, Stags grow antlers in the spring of each year, and as the stag ages, their antlers grow larger. Young stags at around two years old, known as 'prickets', will have grown just the two main antler 'beams'. In successive years, the antler grows thicker and longer, and develops spikes, or 'tines' on the beam. The older the stag, the more 'tines'. On their own, the antlers can reach up to 1.15 meters (45 inches) in length and 5kg (11 lb) in weight, each! In order to compensate, the stag's neck muscles thicken in o