Lifespan Of Rocks
Investigating the lifespan of wild animals is extremely difficult. Since 1986, some rock ptarmigans in the Tateyama region have been fitted with leg bands, making it possible to recognize individuals, and in this way we have been able to understand a little bit more about their lifespan. However, there are too many variables to be able to establish a definitive average lifespan. Sometimes nests are attacked by stoats, or flooded by severe rains, preventing eggs from hatching. Chicks and juveniles have a high rate of early death from cold or attack by predators, so the average lifespan may actually be only a few months. What is now known is that for both males and females that live through their first winter, the average length of survival is about four years.There are, however, many records of individuals living for long periods of time in Tateyama. The longest-lived individuals observed to date are a male that lived for 13 years and a female that lived for 12 years. These records are the longest for any rock ptarmigans found in Japan.
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