There is considerable variation between subspecies in the size of the antlers (e.g. they are rather small and spindly in the northernmost subspecies), but on average the bull reindeer's antlers are the second largest of any extant deer, after the moose. In the largest subspecies, the antlers of large males can range up to in width and in beam length. They have the largest antlers relative to body size among living deer species. Antler size measured in number of points reflects the nutritional status of the reindeer and climate variation of its environment. The number of points on male reindeer increases from birth to five years of age and remains relatively constant from then on. "In male caribou, antler mass (but not the number of tines) varies in concert with body mass." While antlers of bull woodland caribou are typically smaller than barren-ground caribou, they can be over one metre (3') across. They are flattened, compact and relatively dense. Geist describes them as frontally emphasised, flat-beamed antlers. Woodland caribou antlers are thicker and broader than those of the barren-ground caribou and their legs and heads are longer. Quebec-Labrador bull caribou antlers can be significantly larger and wider than other woodland caribou. Central barren-ground bull caribou are perhaps the most diverse in configuration and can grow to be very high and wide. Mountain caribou are typically the most massive with the largest circumference measurements.