Those poor elephants
In August 1943, the administrator of Tokyo, Shigeo Ōdachi, ordered that all "wild and dangerous animals" at the zoo be killed, claiming that bombs could hit the zoo and escaping wild animals would wreak havoc in the streets of Tokyo. Requests by the staff at the zoo for a reprieve, or to evacuate the animals elsewhere, were refused. The animals were executed primarily by poisoning, strangulation or by simply placing the animals on starvation diets. A memorial service was held for the animals in September 1943 (while two of the elephants were still starving) and a permanent memorial (built anew in 1975) can be found in the Ueno Zoo.
Also wtf
Shortly after the March 1945 bombings of Tokyo, the Japanese placed U.S. Army Air Force navigator and bombardier Ray "Hap" Halloran on display naked in a Ueno Zoo tiger cage so civilians could walk in front of the cage and view the B-29 prisoner.