How Long Do Frogs Live? Lifespans of Common Frog Species

Why most frogs never grow old

Frog life starts with huge losses. A female common frog may lay 1,000–4,000 eggs, and an American bullfrog up to about 20,000, yet in a typical pond only a few percent of the young survive to become froglets. Fish, newts, dragonfly larvae, water beetles, birds and drying ponds account for most of the rest.

Froglets then face another dangerous year or two on land, when they are small enough to be eaten by beetles, birds, shrews and snakes. Only a small fraction live to breed. As a result, if you count every egg, the “average” frog lives just a few weeks. Lifespan figures for frogs therefore describe the animals that make it to adulthood. To see how the early stages work, read How do tadpoles turn into frogs?

Lifespans of common frog species

The table lists typical figures for well-studied frogs. Wild figures refer to adults; captive figures are the longest reliably documented records.

How long do common frogs live?

In the wild, most adult common frogs live a few years, and some reach 8 years or more. They become adult at 2–3 years old, so a typical frog may breed in only a handful of springs. Many are taken by herons, grass snakes, otters and other predators, and in some places diseases such as ranavirus or heavy road traffic shorten lives further.

Climate makes a clear difference. In cold mountain and northern populations, frogs are active for only a few months each year, grow slowly and mature late, but they also live longer. The oldest wild common frogs aged by scientists, about 14 years old, came from such populations.

How long do bullfrogs live?

The American bullfrog is a large, long-lived frog. In the wild, adults commonly live about 7–10 years, and the longest documented lifespan is around 16 years for a frog in captivity. Bullfrogs also have one of the longest tadpole stages of any North American frog, often one to three years in the north, which means a big adult bullfrog may be quite old.

Small frogs and short lives

Small frogs tend to have short lives. The wood frog of North America, which survives winter frozen in the leaf litter, rarely lives more than about three years in the wild, and many breed only once or twice. Many small tropical frogs, such as tiny leaf-litter species, probably live only one to a few years, though they are much less studied.

Size is not the whole story, though. Toads often outlive frogs of a similar size, partly because their toxic skin protects them from many predators. The common toad can live about 12 years in the wild and has reached about 40 years in captivity. For more on toads, see How long do toads live?

The longest-lived frogs

Captive records are always longer than wild ones, because a frog in a zoo or laboratory is safe from predators, drought, freezing and many diseases. Among the longest documented frog lifespans are about 45 years for an African bullfrog and about 30 years for an African clawed frog, a species that has been kept in laboratories for decades.

Claims of frogs living for centuries sealed inside rocks or tree trunks, which appeared in old newspapers, are myths. No such case has ever been confirmed, and a frog cannot survive for years without food, water and air.

How scientists tell a frog’s age

Unlike trees, frogs do not show their age on the outside, and size is only a rough guide because growth depends on food and temperature. Instead, scientists use skeletochronology. They take a thin cross-section of a small bone, usually from a toe clipped from a frog that is then released, and stain it.

In frogs from places with cold winters or dry seasons, growth stops each year and leaves a dark line in the bone, called a line of arrested growth. Counting these lines, like tree rings, gives the frog’s age in years. This method has shown that frogs in harsh climates, such as high mountains and the far north, often live longer than frogs of the same species in warm lowlands, because they grow and mature more slowly.

Threats that shorten frog lives

Today, human activities add to the natural dangers. Habitat loss, pollution, road traffic, introduced predators and diseases such as chytrid fungus and ranavirus all reduce how long frogs survive in many places. Amphibians are among the most threatened groups of animals on Earth, and protecting ponds and wetlands gives frogs the best chance to live out their natural lifespans.