Brown bears received large frozen treats filled with fish, fruit and vegetables, while elephants cooled off with water sprays and showers from keepers. The initiative comes as much of Europe experiences a spell of unusually hot weather, with forecasters warning that temperatures could rise further over the weekend. At the zoo, keepers threw the frozen blocks, known as "ice bombs", into the bears' enclosure, encouraging the animals to enter the water and search for food hidden inside the ice.