Giraffes must be listed as endangered, conservationists formally tell US

Five environmental groups point to 'trophy' hunting - largely by Americans who travel to Africa - among key threats to animals

Conservationists have lodged a formal request for the US government to list giraffes as endangered in a bid to prevent what they call the "silent extinction" of the world's tallest land animal.

A legal petition filed by five environmental groups has demanded that the US Fish and Wildlife Service provide endangered species protections to the giraffe, which has suffered a precipitous decline in numbers in recent years.