Pushed to the brink

Dozens of elephants have been killed for their ivory in recent months in Botswana - a country that has been considered elephants' last stronghold in Africa. Conservationists are alarmed are Botswana is home to more than 130,000 elephants-about a third of Africa's savanna elephants-and appeared to have largely escaped the recent ivory poaching crisis.

Isabel Fraser speaks to Rachel Bale, investigative reporter at the National Geographic Society.