Recently I found quite interesting information about the history of the two zoos in Nagoya. This also describes the history of the elephants of the zoos:
名古屋市立動物園100周年
http://www.higashiyama.city.nagoya.jp/anniversary/img/panel.pdf
名古屋市立動物園100周年
http://www.higashiyama.city.nagoya.jp/anniversary/img/panel.pdf