Unfortunately, this does happen. The tusks on the upper half of a male babirusa’s snout grow up and curve back toward its eyes and the top of its head. Sometimes, an older babirusa will have upper tusks that are so long, they break through the top of this animal’s skull. This ingrown tusk eventually causes death. Keep in mind the babirusa would have to be very old to have tusks long enough to penetrate its skull.