One of the most unusual-looking mammals on earth is the babirusa, a wild pig native to the Indonesian archipelago. Humans first colonized Sulawesi approximately 30,000 years ago and soon began hunting and eating babirusas. It’s thought that humans introduced babirusas to Sulu and Buru — although given the babirusa’s swimming prowess, it’s also conceivable that the animals made the journey of their own accord.
Male babirusa are known for their bizarre tusks, which, if they’re not worn down or broken in combat, will eventually grow long enough to pierce the animal’s skull.
Although their large upper tusks appear threatening, the babirusa does not use them as weapons, but rather they serve as a shield for the animal’s eyes during fights. Instead, they use their dagger-like lower tusks to ward off rivals. Since their lower tusks are dull from wearing against the upper ones, the resourceful boar sharpens them by rubbing them against trees.
When males fight, either over mates or territory, they stand side by side and push each other with their shoulders. Then, they face each other, rear up on their hind legs, and jab their heads upwards in order to gore each other with their lower tusks. Besides battling with each other, adult babirusa have few, if any, natural predators to defend against.