The formula for age.

This is aparently old news from the historic land of 2007. But it’s the first time I’ve heard of it.

Life is short for small creatures, longer in big ones. So algae die sooner than oak trees; elephants live longer than mayflies, but you know that. Here's the surprise: There is a mathematical formula which says if you tell me how big something is, I can tell you — with some variation, but not a lot — how long it will live. This doesn't apply to individuals, only to groups, to species. The formula is a simple quarter-power exercise: You take the mass of a plant or an animal, and its metabolic rate is equal to its mass taken to the three-fourths power. I'll explain how this works down below, but the point is, this rule seems to govern all life.

A 2007 paper checked 700 different kinds of plants, and almost every time they applied the formula, it correctly predicted lifespan. “This is universal. It cuts across the design of organisms,” West says. “It applies to me, all mammals, and the trees sitting out there, even though we’re completely different designs.”

This is so, although the relationship is not linear. When Doofus asks Scallywag for his dinner, Scallywag informs him that, say, he has 30 minutes to wait. But in Doofus time that is about 4 hours, which to some extent explains his whining.

It is common knowledge that smaller dog breeds tend to live longer than the larger ones.

All dog breeds are still the same species though, and the variation in life expectancy between different breeds isn’t huge.


There are many exceptions to the rule, e.g. parrots live quite ling for animals their size. As do humans, for that matter. Studying such exceptions may well be instructive: perhaps there is also some simple rule involved.

Well, it does say that the formula estimates a species’ metabolic rate, rather than its lifespan, from an average individual’s weight. Lifespan is thought to be inversely proportional to basal metabolic rate and the ‘constant’ of proportionality will vary from species to species, explaining the exceptions and anomalies. See here.


toitoises? guess their metabolic rates are slooooow…but the big ones are quite heavy.

Yes I’ve heard this before. Humans have a longer possible life span as to what the formula predicts
but the key here is sociability also has an influence on a species life span.

There is a jellyfish that is biologically immortal.

Turritopsis nutricula, the immortal jellyfish, is a hydrozoan whose medusa, or jellyfish, form can revert to the polyp stage after becoming sexually mature.
It appears that heaven is not in the sky, but in the sea.

But isn’t a jellyfish a symbiotic colony of different organisms, which can be ‘hot-swapped’, so the jellyfish itself cannot be said to be immortal? Mind you I suppose you could say the same thing about us–I don’t think I have a single cell in my body that was there in the original new-born.

There’s actually a human cancer harvested from a woman in the 50’s that seems to be immortal as well

EDIT: Radiolab did a really riveting piece about it.

There’s a fascinating book about Henrietta Lacks. Her cancer was the origin of the immortal HeLa cell line. I wish I could remember the quote properly, but apparently the number of HeLa cells propagated in labs around the world would fill a warehouse (sorry, can’t remember what size!)

The Wiki entry on HeLa cells mentions that the infectious cancer decimating the Tasmanian devil population is also caused by an immortal cell line.

That’s exactly what the Radiolab piece is about.

They claim the cells that have been created from the tumor now outnumber the number of cells that were originally in her body.

Fascinating stuff. I also remember that the HeLa strain divides so virulently, that they landed up contaminating lots of other cell experiments in several labs around the world.