Grandparents, life and soul of species

IN the August edition of Scientific American, Rachel Caspari of the University of Michigan claims that old people made a vital contribution to the early development of our species.

Her article ‘The Evolution of Grandparents’ is subtitled ‘Senior citizens may have been the secret of our species success’.

Tooth quality is a good indicator of a person’s age. The first, second and third molars erupt from the ages of six, 12 and 15 years respectively. The teeth wear steadily from then on and by carefully examining them, it’s possible to tell with reasonable accuracy how old their owner was when he or she died.