The sambar deer is a herbivore, with a diet consisting of a variety of plants. It grazes or browses on a range of plant species depending on forage availability at the time, and this allows it to have great habitat flexibility (1) (3). In India alone, the sambar deer has been reported to eat between 130 and 180 different plant species (1). This deer regularly uses mineral licks, which provide essential mineral nutrients, and it is never found far away from a source of fresh water. The sambar deer can easily swim with its body fully submerged and only its head above water (3).
The sambar deer reproduces year-round, but breeding usually peaks seasonally. When in breeding condition, the male has a strong odour and a swollen neck. The male often sprays his body with urine and, standing erect on his hind legs, rubs his odour on trees. Due to regular wallowing in wet spots, the male is usually covered with mud, accentuating his dark fur, and he often acts aggressively during this time (3) (4). During fights, stags may lock antlers, but also rise on their hind legs and crash downwards into their opponent (4).
The female sambar deer reaches sexual maturity at around 18 to 24 months old, and usually gives birth to a single calf after a gestation period of about 8 months (3). Female sambar deer usually occur in small groups, which are often dominated by a single female. Young males group together close to females, while males over six years of age are typically solitary. Group size is normally at its largest near water holes (3).
The sambar deer is fairly shy and is mainly active at twilight or at night (3). This species is very alert and silent, and will freeze instantly if disturbed. The sambar deer is one of the few deer that attacks sizeable predators, and it prefers to hold confrontations in shallow water (4). When confronting predators, the sambar deer produces a loud alarm bark and the hair on its neck erects. A female sambar deer is also incredibly protective of her young and, if confronted, will stomp and warn off attackers (3).
Sambar deer have a sex ratio greatly favouring females, due to the high mortality of males. This is mainly due to predation by animals such as the leopard, tiger and wolf (4). Predation by tigers (Panthera tigris) is a major cause of sambar deer mortality, with the sambar deer making up a large proportion of tiger prey in many areas (1).