In the wild, tigers mostly feed on large and medium-sized animals, preferring native ungulates (horses, cattle, pigs, giraffes,camels, deer, and hippopotamuses) weighing at least 90 kg (200 lb). They also prey on other predators, including dogs, leopards, pythons, sloth bears, and crocodiles. Sambar deer, chital, barasingha, wild boar, gaur, nilgai and both water buffalo and domestic buffalo, in descending order of preference, are the tiger's favoured prey in India.
In Siberia, the main prey species are Manchurian wapiti and wild boar (the two species comprising nearly 80% of the prey selected) followed by sika deer, moose, roe deer, and musk deer. Asiatic black bears and Ussuri brown bears may also fall prey to tigers, and they constitute up to 40.7% of the diet of Siberian tigers depending on local conditions and the bear populations.
In Sumatra, prey includes sambar deer, muntjac, wild boar, Malayan tapir and orangutan. In the former Caspian tiger's range, prey included saiga antelope, camels, Caucasian wisent, yak, and wild horses. Like many predators, tigers are opportunistic and may eat much smaller prey, such as monkeys, peafowl and other ground-based birds, hares, porcupines, and fish.
Tigers generally do not prey on fully grown adult Asian elephants and Indian rhinoceros, but incidents have been reported. Tigers have been reported attacking and killing elephants ridden by humans during tiger hunts in the nineteenth century. When in close proximity to humans, tigers will also sometimes prey on such domestic livestock as cattle, horses, and donkeys.
Old or wounded tigers, unable to catch wild prey, can become man-eaters; this pattern has recurred frequently across India. Although almost exclusively carnivorous, tigers will occasionally eat vegetation for dietary fibre. The fruit of the slow match tree is a favorite.
They generally hunt alone and surprise attack their prey as most other cats do, overpowering them from any angle, using their body size and strength to knock the prey off balance. Successful hunts usually require the tiger to almost simultaneously jump onto its prey, knock it over, and grab the throat or nape with its teeth.
When hunting larger animals, tigers prefer to bite the throat and use their powerful forelimbs to hold onto the prey, often simultaneously wrestling it to the ground. The tiger remains latched onto the neck until its target dies of strangulation. By this method, gaurs, and water buffaloes weighing over a ton have been killed by tigers weighing about a sixth as much. Although they can kill healthy adults, tigers often select the calves or infirm of very large species.
Tigers also prefer hunting at night time and their night vision is 6 times powerful than that of humans. After killing their prey, tigers sometimes drag it to conceal it in vegetative cover, usually pulling it by grasping with their mouth. An adult tiger can go for up to two weeks without eating, then gorge on 34 kg (75 lb) of flesh at one time. In captivity, adult tigers are fed 3 to 6 kg (6.6 to 13.2 lb) of meat a day.