how old are sea turtles

How Old are Sea Turtles

Sea turtles are one of the oldest living creatures on earth. They can live for over 100 years in some cases, and tend to reach sexual maturity at around 50 to 70 years of age. It is very hard to accurately determine the age of a sea turtle, as they do not possess internal rings like those of a tree or have cartilage like those of bony fish.

Age Inticators

Due to the difficulty in aging sea turtles, investigators have studied and developed methods to estimate the age of these animals. Below are some of the age indicators used to determine the age of a sea turtle.

  • Size – The size of the animal is used to estimate its age. In general, the bigger the turtle, the older it is.
  • Osmoregulation – It has been found that marine turtles reach a full size faster in areas with higher salinity and reach their full maturity quicker in areas with lower salinity.
  • Value adders – Researchers also incorporate chronologies from satellite images, historical photographs, published reports, and other methods to estimate a turtle’s age.

Age Hypotheses

There are several hypotheses that researchers have made to more precisely estimate the age of sea turtles.

  • Odontogenic Hypothesis – According to the odontogenic hypothesis, bony deposits form the inside of the shell with age, therefore the shell thickness is used to cycle through the size of each annual growth layer and estimate the age of the turtle. This hypothesis is yet to be proven with scientific studies.
  • Weight-Length Hypothesis – The weight-length hypothesis is used to estimate the age of the turtle by analyzing weight and length measurements. This hypothesis has been studied the most and is based on the assumption that all turtles, regardless of species, have a similar body-length to weight ratio.
  • Incisive Ridgy Hypothesis – This hypothesis suggests that rings are visible on the incisive ridges (ridge-like teeth) of the upper and lower jaws of older turtles. However, this hypothesis has been largely discredited as there is no consensus on the existence of visible rings in turtles.


Sea turtles are the oldest living creatures on earth with some of them capable of living to over 100 years of age. There is no easy way to accurately determine the age of a sea turtle, so researchers have developed methods to estimate their age. These methods generally include size, odontogenic, weight-length and incisive ridgy hypotheses.

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