How Long Do Dolphins Live? Lifespan in the Wild

How long do bottlenose dolphins live?

NOAA gives the lifespan of the common bottlenose dolphin as 40–60 years. Dolphins can live at least 40 years, and some females outlive males and reach 60 or more. On average, females live about 5–10 years longer than males.

These figures describe dolphins that survive to adulthood. The first year of life is the most dangerous: calves can be lost to sharks, disease, separation from their mother or the inexperience of a first-time mother, so the average age at death across a whole population is much lower than the maximum.

Bottlenose dolphins breed slowly, which suits a long life. Females usually have their first calf between 5 and 15 years of age, depending on the population, then give birth about every 3–6 years after a 12-month pregnancy. Females as old as 45 have given birth, and NOAA notes that bottlenose dolphins are likely among the few mammals that go through menopause.

The oldest known wild dolphins

Exact ages of wild dolphins are only known where scientists have followed the same animals for decades. The best example is the Sarasota Dolphin Research Program in Florida, which began in 1970 and is the world’s longest-running study of a wild dolphin population. Researchers recognize each dolphin from the nicks and notches on its dorsal fin, so they know when many of the local dolphins were born and when they died.

Over more than 50 years, the program has documented six generations of dolphins in Sarasota Bay, including Nicklo, the oldest known wild dolphin, who lived to 67. Long-term studies such as this, and similar ones in Shark Bay, Australia, and Scotland’s Moray Firth, are among the main sources of reliable figures on how long dolphins live.

Why do females live longer?

The gap between the sexes appears in many dolphins, including orcas, but the reasons are not fully understood. Male bottlenose dolphins compete hard for access to females, often in pairs or alliances, and fights leave rake marks and other injuries. Males, especially those in pairs, also roam over wide areas, which may expose them to more hazards, from sharks to boats and fishing gear.

Females, by contrast, tend to stay within familiar home ranges and in stable social groups. Whatever the cause, the pattern is consistent: in most long-term studies, the oldest dolphins are females.

How do scientists tell a dolphin’s age?

The classic method uses teeth. A dolphin’s teeth grow throughout its life, laying down a new layer of dentine each year. When a thin slice of tooth is stained and viewed under a microscope, the layers appear as bands that can be counted, much like tree rings. In 1989, researchers checked this method against teeth from Sarasota dolphins of known age and confirmed that bottlenose dolphins add about one layer group per year.

Tooth counts become less precise in very old animals, whose layers grow thin and crowded, so the ages of the oldest individuals may be underestimated. Researchers can now also estimate age from chemical marks on DNA, called methylation, in a small skin sample taken from a living dolphin. For dolphins followed since birth, photo identification gives an exact age.

What shortens a dolphin’s life?

Natural causes include predation, disease and food shortages. In Sarasota Bay, about 36% of dolphins carry at least one shark bite, mostly from bull and tiger sharks. Harmful algal blooms, such as Florida’s red tides, can poison dolphins through their prey.

Human activities often play a bigger role. Dolphins drown in fishing nets, become entangled in or swallow fishing line, and are hit by boats: about 1 in 20 Sarasota dolphins carries a scar from a boat strike. Pollutants such as PCBs build up in their blubber and are passed to calves in milk, and dolphins exposed to the 2010 Deepwater Horizon oil spill suffered lung disease and pregnancy failure.

How long do other dolphins and porpoises live?

Lifespans vary widely across the family. Larger species generally live longer than small ones.

Porpoises live fast and die young: a female harbor porpoise can breed at 3–4 years old and may calve every year, a very different strategy from the slow, long life of a bottlenose dolphin, as explained in dolphin vs porpoise. For whales, see How long do whales live?, and for record holders across the animal kingdom, see our list of the longest-living animals. For more on the species itself, visit our common bottlenose dolphin profile.