Elephants (IMAGE) Princeton University Caption Male elephants of breeding age -- over 28 years old -- make up more than 5 percent of well-protected populations. Where populations have been over-exploited, this percentage declines to 1 percent or less. Males that resemble Amboseli National Park's "Tolstoy" are unlikely to live to pass on their genes for large tusks. Credit Joyce Poole/Elephant Voices Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.