Species Longevity

I’ve never had but one wrinkle, and I’m sitting on it.

Figure 1: A bowhead whale breaches off the coast of western Sea of Okhotsk (Olga_Shpak).

Figure 1: A Bowhead Whale Breaches
off the Coast of Western Sea of
Okhotsk (Olga Shpak).

I am always surprised when I read about how long some members of the animal kingdom live. Back in 2007, I saw an article about a bowhead whale (Figure 1) that was confirmed to have lived ~130 years. In fact, there is some chemical evidence that one bowhead whale may have lived to be 211 years old.

The whale that died in 2007 was able to be more precisely aged because it had been wounded back in the 1880s by a harpoon with a specific type of harpoon head (Figure 2), which was left behind in the whale and could be dated to the 1880s. Generally, whale ages are difficult to confirm because they can only be roughly aged by protein rings that makeup the lens of the whale's eye (Figure 3).

Figure 1: 1880s Harpoon Head Found in Bowhead Whale That Died in 2007.

Figure 2: 1880s Harpoon Head Found in Bowhead Whale That Died in 2007.

Figure 3: Whale Eyes Have Rings Like Trees.

Figure 3: Whale Eyes Have Rings Like Trees.

Today, I saw the following graphic that shows the ages of some long-lived species (Figure 4). You can see that the bowhead whale's lifetime is just a bit more than half of the ocean quohog, a type of clam.

Figure 4: Longest Lived Animals.

Figure 4: Longest Lived Animals.

There is a well-known speculation, called the Heartbeat Hypothesis, that every animal has a limited number of heartbeats – it is also called the "billion beat hypothesis" because most species seem to get ~1 billion heartbeats in a lifetime. Here is a PBS video that does a good job describing the hypothesis. The video also does a nice job explaining the  quarter-power scaling principle, which some folks use to explain why larger organisms (e.g. turtles) tend to live longer than smaller ones (e.g. shrews).

The maximum longevity of a species can be quite different from the average. A great illustration of this point comes from the famous tale of Jeanne Calment, the oldest woman in history, who died at 122 years old.

One interesting story about her involved an man who wanted the rights to her apartment when she died, which is a common arrangement in France. When she was 90, the man paid 2500 francs per month for the rights to her apartment when she died. He had no idea she would outlive him. Here is a quote from the Wikipedia on the subject (see also the New York Times article on her).

In 1965, at age 90 and with no heirs, Calment signed a deal to sell her apartment to lawyer André-François Raffray, on a contingency contract. Raffray, then aged 47 years, agreed to pay her a monthly sum of 2,500 francs until she died. Raffray ended up paying Calment the equivalent of more than $180,000, which was more than double the apartment's value. After Raffray's death from cancer at the age of 77, in 1995, his widow continued the payments until Calment's death. During all these years, Calment used to say to them that she "competed with Methuselah".

This entry was posted in General Science. Bookmark the permalink.