Do tigers mostly die of starvation in old age?

Yes. When a carnivore becomes incapable of hunting due to injuries, age or sickness, they resort to scavenging or turn towards non-natural prey such as humans. When all else fails, the result is slow, painful starvation to death. read more

Old age leads to degradation in hunting skills. As a result, looking for easy prey like village cattle and animals. Villagers retaliate and lead to tigers death. If easy prey is not so easy to get, starvation sets in. Another reason is younger ones making a claim for their territory. Fighting with younger tigers can lead to injuries, broken canines. read more

In a sense, this is dying of old age, but I think you mean "left alone to die with no interference." This would depend on lots of things, including the ratio of predators to prey, which is highly variable. read more

Workers, in most species, die after a few months. Although some insects do die of old age in the wild, nature is harsh. Most freeze to death, overheat, starve or become someone’s lunch. Insects who die of old age are lucky, and they combat high mortality rates by making lots of babies. read more