Kojima shared some new information about the animals in Metal Gear Solid V: The Phantom Pain during Kojima Station. In the latest episode, Kojima looked back at the various animals that have appeared in earlier games in the series. Then, they talked a bit about the animals in The Phantom Pain, some of which we have already seen in trailers.
The animals will attack both you and your enemies. Kojima said he was checking the game recently, when a Soviet soldier was attacked and eaten by a wild animal. “When asked if animals will attack each other, Kojima nodded and smiled.” (translated by JunkerHQ). So you’ll need to be careful not only for soldiers, but for wildlife as well. But, you may also be able to use them to your advantage. “Kojima also said you can use the animal capture system to get them to attack enemies for you.” (JunkerHQ). It sounds like you may be able to drop them near an enemy to cause some mayhem.
The day/night cycle also has an effect on the animal system, the time of day will probably determine what wildlife you’ll run into.
Yet another element to play around with in the game, from the looks of it. Aside from using them to build you zoo, of course.
Source: Kojima Station Episode 28, Junker HQ Twitter