Grab the biggest shotgun you can find because there's a new reason to revisit Bethesda's final expansion for Fallout 4. The Mutant Menagerie—Nuclear Safari mod populates Nuka World with lots of new animals and creatures to hunt including giraffes, flamingos, zebras, and best of all, elephants.
Granted, these animals are all gross and mutated—the flamingos have a few extra eyes and the elephants in particular look like they'd been deep fried in orange juice—but that sort of thing tends to happen when a bunch of nukes get dropped on the world.
If it's been a while since you've played Fallout 4, Nuka World was the last expansion for the game and included a massive, raider-controlled amusement park for high-level (30 and above) characters. As for why the mod adds a bunch of new animals, it's because Nuka World also features a zoo, and these modded creatures will randomly spawn in the area as if they escaped during the war and mutated—like Fallout's ghouls, they got extremely ugly yet could live for centuries. Makes sense to me: If radiation can make hermit crabs the size of a city bus, I don't see why there can't be a few crispy elephants running around, too.
Not everything in the mod is hostile. There are some passive creatures who won't cause you trouble, like the flamingos and giraffes. Some creatures, like elephants, will only become hostile if you attack first. And there are plenty of beasts eager to kill you on sight, like several variations of rats, irradiated hyenas, and "nighthunters," which are a deadly hybrid of a mountain lion and rattlesnake. On the plus side, killing some of these horrifying creatures will provide you with resources and recipes fit for a theme park, like "bug nuggets" and nuka burgers. Yum!
Nuclear Safari is itself an expansion to the long-running Mutant Menagerie mod series, which has steadily brought new creatures and horrors to Fallout 4's map, including areas added by DLC packs like Far Harbor. You can see some of the creatures in Nuclear Safari in this video by Degenerate Dak on YouTube below, and you'll find the earlier Mutant Menagerie mods here.