THE KALINGOI (or Calingi) were an extremely short-lived Indian tribe who reached maturity at the age of five and died of old age at eight.

Pliny the Elder, Natural History 7. 30 (trans. Rackham) (Roman encyclopedia C1st A.D.) :
"Duris [a Greek historian C3rd B.C.] says ... that among the Calingi, a tribe of he same part of India, women conceive at the age of five and do not live more than eight years."

Sources:

• Pliny the Elder, Natural History - Latin Encyclopedia C1st A.D.