Rwandan veterinarian Olivier Nsengimana tells us about his mission to save the endangered grey-crowned crane, an elegant bird that represents wealth and prosperity but has been poached for people to keep as a pet.

The whale shark is the largest fish in the world, recognisable by its celestial markings. Australian scientist Brad Norman has been tracking this elusive and endangered creature by using technology designed to study stars, as well as images collected through ecotourism. Norman is based in Perth,...