Because we have studied the Sarasota dolphins for decades, we now know the ages of most of the community members.
Regular SDRP boat surveys let us observe new calves soon after birth, when they are closely associating with their well-known mothers. Ideally, they acquire natural markings before they leave their mothers 3-6 years later, so that we can identify them for the rest of their lives.
For dolphins of unknown age, we can estimate their age if a tooth can be examined. Like the growth rings in trees, dolphin teeth have annular layers. Annual layers are added from the outside in, gradually filling up the cavity in the middle of the tooth.
Female dolphins live longer than males, and may give birth when they are as old as 48 years of age. The oldest dolphin we know in the Sarasota Bay dolphin community is a female named Nicklo, who was estimated to be 60 years old in 2010.
Males may live into their forties. Our most long-lived male dolphin, nicknamed Jimmy Durante, was 50 years old when last seen in 2009.
We also sadly watch dolphins as they near the end of their lives. The photo at left was our last opportunity to see the 54-yr-old Ms. Mayhem alive. Her body was recovered just nine days later.
Hohn, A.A., M.D. Scott, R.S. Wells, J.C. Sweeney and A.B. Irvine. 1989. Growth layers in teeth from known-age, free-ranging bottlenose dolphins. Marine Mammal Science 5(4):315-342.
Wells, R.S. and M.D. Scott. 1999. Bottlenose dolphin Tursiops truncatus (Montagu, 1821). Pp. 137-182 In: S.H. Ridgway and R. Harrison (eds.), Handbook of Marine Mammals, Vol. 6, the Second Book of Dolphins and Porpoises. Academic Press, San Diego, CA. 486 pp.