According to PBS, the average life span of a shark is 25 years. Life expectancy can vary among shark species. Sharks tend to live much longer in the wild than in captivity.
The longest-living shark is the spiny dogfish, which can live from 75 to 100 years, while its cousin, the blue shark, only lives 15 to 16 years in the wild. Great white sharks live between 25 and 30 years. Tiger sharks live for an average of 27 years, but have been known to live to be 50. When sharks are taken into captivity, their lifespan can decrease up to 50 percent.