"You Look Good for Your Age"

By By Tamra Werner

Author of Koli, The Great White Shark books

This 400-year-old Greenland shark gives a new meaning to "you look good for your age!" So, how do scientists determine a shark's age, and what are the stages of a shark's lifecycle?

Scientists measure size, weight, length, and sometimes environmental indicators such as the nucleus of the Greenland shark's eye tissue to determine their age.

Are the gestation and life stages all that different between humans and sharks? Let's take a look.

Human Shark

Gestation Gestation

9 months 5-36 months, depending on the type of shark

Zebra 5 months (1-10 pups in egg cases)

Great White 12 months (2-12 pups live birth)

Tiger 13-16 months (10-80 pups live birth)

Hammerhead 11 months (6-50 pups live birth)

Basking 36 months (1-6 pups live birth)

Whale Shark unknown (300 pups live birth)

Newborn/Toddler Pup/Young of Year

Pre/Adolescence Juvenile

Adolescence /Teenager Sub-Adult

Adult Adult (reached sexual maturity)Senior Adult N/A

Maybe Greenland sharks need a new category of senior adults. Regardless, they sure look good for their age!

Koli's Birthday Adventure and Koli's Friendship Adventure books educate and entertain children about the marine ecosystem through Koli's adventures, friendships, and STEM learning sections.