Uno et al., PNAS, 2013.
Longitudinal slices taken from an elephant molar for dating. Like tree growth rings, layers of enamel indicate the passage of time.
Can nuclear bombs help elephants?
This is Sandra Tsing Loh with the Loh Down on Science, saying, indirectly, yes.
Poor pachyderms! Their numbers are dwindling because hunters kill them for their tusks.
Ivory hunting was banned in 1989. But poachers still illegally slay 30,000 elephants each year. Uh!
Enter paleo-ecologists from Columbia University. They’ve developed a method to pinpoint a tusk's age. The key? Nuclear bombs!
See, during the Cold War, scientists exploded lots of nuclear bombs! These tests temporarily doubled the atmosphere’s levels of the radioactive element carbon-14. Scientists call this midcentury spike the “Bomb Curve.” Levels have been decreasing in a known way ever since. —Scientists have precisely charted it.
And that's useful how? Well, animals take in C-14 while alive but stop when they die. The researchers can check tusks for C-14 that corresponds to post–1989 levels. Meaning the animals died—and the tusks were acquired—post-ban. The test should be good for about fifteen more years, before C-14 falls back to pre–Cold War levels.
So beware, poachers. Elephant tusks never forget.
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