Their tusks are also teeth, the second set of upper incisors become the tusks. They are used for digging for roots and stripping the bark off trees for food, and, fighting each other during mating season, or defending themselves against predators. They weigh from 50-100 pounds and may be from 5 to 8 feet long. However, a result of poachers killing elephants with the biggest tusks has been a survivor population with much smaller tusks. Both bulls and cows have tusks.