I mean seems pretty obvious why. Like the size ofcourse but also how is one supposed to feed a baleen whales, let alone a group of them? Like with orcas, belugas and dolphins its easy enough getting enough fish for them, but baleen whales, depending on size eat literal tons of zooplankton every dayPlanet Zoo didn't even have whales and fish yet so why blue whale? Anyone knew or guess why there weren't whales that were bigger than orcas in captivities?