The average tusk size of African elephants has halved since the mid-19th century. A similar effect has been spotted in the Asian elephant population in India.Researchers say it is an example of Darwinism in action, caused by the mass slaughter of dominant male elephants - but whereas evolution normally takes place over thousands of years, these changes have occurred within 150 years.
Zoologists at Oxford University fear that poaching and hunting of the largest male elephants, which also have the largest tusks, has changed the natural breeding behaviour of these animals. Their research has shown that the hunting of these large males for their ivory allows smaller males with shorter tusks to produce more calves. Over time the average tusk size decrease
Source: Telegraph
