View image in fullscreenA robber fly is photographed in Puerto Jiménez, Costa Rica. Also known as “assassin flies”, they are aggressive aerial predators, known for intercepting and capturing other insects in flight. They have even been known to attack humans when threatenedPhotograph: Ronen Tivony/NurPhoto/ShutterstockShareView image in fullscreenYoung punks … an egret tends to its chicks in their nest on the outskirts of Ajmer, IndiaPhotograph: Himanshu Sharma/NurPhoto/ShutterstockShareView image in fullscreenTwo brown bears at the Arcturos bear sanctuary in Nymfaio, northern Greece,