Either food scarcity or excessive hunting can threaten a population of animals  If the group faces food scarcity, individuals in the group will reach reproductive maturity later than otherwise  If the group faces excessive hunting, individuals that reach reproductive maturity earlier will come to predominate
Ttherefore, it should be possible to determine whether prehistoric mastodons became extinct because of food scarcity or human hunting, since there are fossilized mastodon remains from both before and after mastodon populations declined, and
it can be accurately estimated from fossilized remains when mastodons became extinct