LizBonninpresentsacontroversialandprovocativeepisodeofHorizon,investigatinghownewscientificresearchisraisinghardquestionsaboutzoos-thefilmexploreshowandwhyzooskeepanimals,andwhethertheyneedtochangetokeepupwithmodernscienceorultimatelybeconsignedtohistory.Shouldzoosculltheiranimalstomanagepopulations?LiztravelstoCopenhagenZoo,whokilledagiraffeandfedittothelions,towitnesstheircullingprocessfirsthand.Theythinkitisanaturalpartofzookeepingthatisoftensweptunderthecarpet.Shouldsomeanimalsneverbekeptincaptivity?Inaworldexclusive,LizvisitsSeaWorldinFloridaandasksifcaptivitydroveoneoftheirorcastokillhistrainer.Butcouldzoosbetheanswertoconservingendangeredspecies?Lizexaminestheirrecord,fromhelpingbreedpandasforthewildtoeffortstosavetherhinos.Shemeetsoneofthelastsurvivingnorthernwhiterhinosanddiscoversthefutureofthisspeciesnowliesinamultimillion-dollarprogrammetoengineerthemfromstemcells.VeteranconservationscientistDrSarahBexelltellsLizthescienceofcaptivebreedingisgivinghumanityfalsehope.