Long-Lived Animal Species and What They Reveal About Aging

Researchers estimated that the largest Greenland shark in a radiocarbon study was between 272 and 512 years old. The sample came from the core of its eye lens, tissue laid down before birth that keeps its early carbon signature. Even the low end puts this shark’s lifespan on the scale of centuries.

One ocean quahog collected off northern Iceland lived for 507 years, according to its shell. The researchers first estimated it at about 405 to 410 years. Matching patterns of annual growth among shells alongside closer reading of the increments helped produce a longer count. Even a good shell can be difficult to read.

Old whaling implements recovered from bowheads suggested that some animals had lived more than a century. Eye lenses provided a way to estimate ages using changes in the molecular form of aspartic acid. The estimates for several whales exceeded a century, giving independent evidence of a lifespan out of reach for most mammals.

Aldabra giant tortoises can live for more than a century. Their documented time in human care can be easier to pin down than their birth dates. Two Smithsonian residents arrived in 1976 and were already adults, so the zoo gives an age estimate for them. A dated arrival is a firm anchor for a long, partly unrecorded life.

A captive colony gave researchers decades of records on this cave salamander. The oldest animals had been followed long enough for a lower bound of 48 years, with their earlier ages unknown. A projection based on those records put the maximum lifespan beyond 100 years. The long observation and the longer prediction answer different questions.

In captivity these small rodents have lived beyond 30 years. In a study spanning about 35 years of age, their risk of dying at any given time stayed low across the observed ages. That population measure can tell us how the pace of aging differs from the number of years a single animal lives.

A large red sea urchin can live past a century. Researchers compared growth estimates from marked animals with radiocarbon signatures in pieces of the jaw skeleton. Carbon from mid-century nuclear testing supplied a date marker. The two kinds of evidence let researchers check whether slow growth could really yield such old animals.

Monorhaphis chuni This deep-sea glass sponge anchors itself with a long silica spike. By comparing chemical changes across layers of one spike with past ocean temperatures, researchers estimated about 11,000 years of growth, with uncertainty of about 3,000 years in either direction. The green-tinted photograph in the comparison figure shows the sponge on the seabed.

An Alaska rockfish first identified as a rougheye was assigned an age of 205 from a section of an otolith, a hard structure in the inner ear. Some growth marks were difficult to distinguish, and the author gave about 170 years as a lower reading. Later work separated two similar rockfish species, another reason to read that famous figure with care.

The gap between two captures can be more informative than the animal’s appearance. A banded bat from Siberia was caught again 41 years after it was first marked, giving a firm minimum. The paper called it a Brandt’s bat. The population at the site is now assigned to the Siberian bat.

Lake sturgeon can live more than a century, and counting the growth marks on a fin spine can give an age that is too young. A study checked counts against known-age fish and the radiocarbon marker from nuclear testing. The error increased with age, while counts from inner-ear structures worked better across the ages the team could check.

The Laysan albatross shows what a long-running banding program can establish. Wisdom was already breeding when biologists first banded her at Midway Atoll in 1956. Because Laysan albatrosses aren’t known to breed before age five, later sightings tell us she had lived into her seventies even though nobody recorded her hatching.

In a study of freshwater pearl mussels from Finland and Sweden, the oldest estimates varied widely between populations. Shell growth records gave maxima from 54 to 254 years in the sampled groups. The variation matters as much as the upper end when we talk about the lifespan of a whole species.

New Zealand’s tuatara can live for many decades. So how slowly does the risk of death rise with age? In a comparative study of wild reptiles and amphibians, data from the study’s one tuatara population pointed to a very shallow rise. That is a population result from repeated observations, distinct from the age estimated for an individual.

A Pacific geoduck adds annual growth marks even after its shell stops getting much longer. Researchers matched the timing of those marks across shells and found one record spanning 179 years. The gap between a clam’s size and its age helps explain why a measuring tape gives a different answer from a shell section.