Columbian mammoth
Columbian mammoths had very long tusks (modified incisor teeth), which were more curved than those of modern elephants. The largest known mammoth tusk, long, belonged to a Columbian mammoth, and others range from long. Columbian mammoth tusks were usually not much larger than those of woolly mammoths, which reached . The tusks of females were much smaller and thinner. About a quarter of the tusks' length was inside the sockets; they grew spirally in opposite directions from the base, curving until the tips pointed towards each other, and sometimes crossed. Most of their weight would have been close to the skull, with less torque than straight tusks would have generated. The tusks were usually asymmetrical, with considerable variation; some tusks curved down, instead of outwards, or were shorter due to breakage. Columbian mammoth tusks were generally less twisted than those of woolly mammoths. At six months of age, calves developed milk tusks a few centimeters long, which were replaced by permanent tusks a year later. Annual tusk growth of continued throughout life, slowing as the animal reached adulthood.