Further observations on savannah elephant tusks

Abstract

The paper analyses weights of 2,425 tusk pairs, and lengths of 398 pairs obtained between 1965 and 1969 from two East African savannah elephant populations, one in Uganda, the other in eastern Kenya and north-eastern Tanzania. They are presented as averages in five-year age cohorts. Separately, length, weight and gender showed no significant differences between the use of the right and left tusks. If neural lateralization exists in elephants, it is concealed by the dynamics of tusk growth and wear, which are described. The fact that average asymptotes at age are only 31% (female) and 38% (male) of the theoretical asymptotes is explained by weathering and wear. Contrary to expectations that single tusks, having to do the work of two, would be shorter than the pair average, they are not, but stay within pair length parameters. Evidence is presented that declining tusk growth occurs in both sexes with advanced age. The longer-tusk pairs have a tight curvilinear relationship to average shoulder height, rising evenly from 24% (females) and 26% (males) under 6.5 years to 58% and 76% respectively in the oldest age classes. That is, they relate to an elephant’s height.