Wrong exhibit after birth:
Whenever an animal inside a water tank exhibit gives birth, occasionally it will have its baby in another exhibit other than one with a water tank. For example, a dolphin born in a koala exhibit.
Dolphins glitch:
Glitched dolphins appear when you have two dolphins, male and female, and at least one other animal cage that is not a sea animal. Normally when the other animals have a baby, a dolphin appears with it. The dolphin will appear to be swimming, even when on land. When you click on the dolphin, the game will freeze. However, there is one way to view the glitch dolphins heath stats. First, tap any other animal in the cage (unless there are multiple glitched dolphins, in that case tap a regular animal), then press the L or R until the arrow lands on the glitched dolphin. You can now view its stats and go to Zookeeper mode. Note: It is best to save your game before attempting this, because the entire screen will turn black after you are done in Zookeeper mode. There is only one way to get rid of the glitched dolphins. First, build a sea animal tank. Second, try to move the glitched dolphins to the tank. After that, save the game. Finally, try to sell the glitched dolphin(s). Note: On the first try, your game will freeze.