Answer:
Determining the lifespan of sharks is a difficult task as they are very tough to monitor in the ocean because of their migratory and feeding patterns. Even more, the life expectancy of sharks in captivity is considerably shorter than those in the wild, making impractical to generate deductions from those individuals in aquariums.
Lately, GPS technology has provided a new approach to tracking migration patterns and life habits of sharks, providing more precise data about them.
Shark lifespan varies by species. Although most of them live 20 to 30 years in the wild, there are some that live much longer than others.
For example, the spiny dogfish has one of the longest lifespans on Earth with more than 100 years, while the blue shark in the wild has an average life expectancy of 15-16 years. Nevertheless, as we mention before, blue shark lifespan lowers down to 8 years when held in captivity, perhaps as a result of the inactivity inherent to captivity.
Whale sharks (Rhincodon typus) are also thought to live above 100 years, suggesting that the time to reach sexual maturity is long and the offspring will require more time to born. Some experts believe that the number of growth rings on a whale sharkâs vertebrae may be an indicator of its age. In captivity, whale sharks are not comfortable, and in a few cases they have died within days, but at most, they have reached only eight years.
Some scientists believe that the life expectancy of the Great White Sharks is around 30 years (Levine, 1988) but other research indicates that they can reach up to 40.
The lifespan of Tiger Sharks in the wild is believed to be 27 years in average, although some may live up to 50 years of age. Like with other species, tiger sharks in captivity do not live as much as in wildlife reaching only 17 to 20 years.
The repercussion of captivity in the lifespan of Leopard Sharks is certainly dramatic; if they are in small tanks, they have a low expectancy of approximately nine years while large aquarium tanks can help them to have a longer life that can reach up to 25. In the wild, their life expectancy is 30 years.
The typical lifespan in the wild for Hammerhead Sharks is from 20 to 30 years approximately.
Sandbar sharks or Brown sharks are considered to live between 20 and 30 years. Research made by Joung (2004) identified this to be about 20 years, while Sminkey (1996) mention that sandbar sharks can live more than 30 years.
Counting the quantity of growth rings that develop on their vertebrae can determine the age of the silky or Blackspot sharks as with other species, with each ring standing for around one year of life. Silky Sharks can live up 25 years in the wild.
Links to other pages in this site
How Much Do Sharks Weight?
Why Are Sharks Dangerous?
How Long Do Mother Sharks Carry Their Babies?
What Color Is The Hammerhead Shark?
How Many Years Does A Shark Live For?