Three U.S. airlines banned the shipment of hunting trophies this week after the killing of Cecil the lion in Zimbabwe last month.
Delta Air Lines was the first to announce the ban on Monday. It was soon followed by American Airlines and United Airlines. The decisions come after similar measures were taken by Emirates and South African Airways.
It is not clear how many, if any, hunting trophies the U.S. airlines have transported in recent years.
The ban prevents carrying lion, leopard, elephant, rhinoceros and buffalo trophies on the flights of the U.S. airlines.
The measure came after an American dentist, Walter James Palmer, killed the well-known lion Cecil outside Hwange National Park in Zimbabwe in an allegedly illegal hunt.
Zimbabwe is seeking the extradition of Palmer from Minnesota, a major hub for Delta, who killed Cecil the lion in early July.
It is reported that Zimbabwe is also seeking the extradition of a doctor from Pennsylvania, Jan Casimir Seski, suspected of killing a lion in April.
There is an extradition treaty between Zimbabwe and the United States.
The killing of Cecil drew worldwide condemnation and drew further global attention when the United Nations General Assembly unanimously adopted a resolution last week aimed at combating illegal wildlife trafficking and poaching. It was the culmination of a two-year campaign led by Gabon and Germany.