Detroit Zoo has bought in an amphibian “sexpert” to encourage its creatures to mate. Experts predict half of the world’s known species of amphibians is threatened, with lack of breeding a major issue. She’s new to the job – but that’s not stopping Dr Ruth Marcec from getting up close and personal with her new friends at Detroit Zoo. In fact as director of the National Amphibian Conservation Centre, and reproduction expert, it’s what her new role’s all about. She’s been tasked with encouraging intimacy between creatures such as frogs and salamanders to encourage them to mate more. Experts estimate that around half of the world’s 7,600 known species of amphibians is threatened.