If we had the scientific capability to bring back extinct species should we do it? Which ones would we choose and why? How about woolly mammoths roaming across the Arctic tundra, or vast flocks of passenger pigeons – once the most numerous birds on earth – back in our skies again? Scientists believe they are on the threshold of the technologies that could make all this possible. But could the power to bring animals back make us more complacent about their extinction? And what might the consequences be for the habitats into which they’re introduced? On this week’s Newshour Extra Owen Bennett Jones and his guests take a step back from the global news agenda to consider one of the great challenges facing biological and environmental scientists today. (Photo: artist's impression of a woolly mammoth. Credit: Thinkstock)