Underpaid, ill-equipped and outnumbered, park rangers fight a one-sided war against vicious gangs of poachers. Hundreds have been murdered in the defence of endangered wildlife, and their deaths leave their own families in jeopardy. David Smith reports from Zambia.

http://www.guardian.co.uk/theobserver/2013/jun/15/poachers-africa-thin-green-line?