From Mesa, Ariz., at a meeting of the Society of Vertebrate Paleontology
Tusks of juvenile mammoths carry a chemical record of the animals' environment and behaviors, including how quickly they became weaned from their mothers, scientists have found.
As the tusks of modern elephants do, a mammoth's tusks grew continuously from birth. Features in the ancient ivory, analogous to the growth rings of a tree, chronicle years, weeks, and even individual days in a mammoth's life, says Adam N. Rountrey of the University of Michigan in Ann Arbor. The proportions of nitrogen and carbon isotopes present in tusk material reflect what an ani