Relatively slow testicular growth characterizes the first 6 years of life. Following this period, gonad development is rapid and by 9 to 11 years of age the testicular components reach adult percentages.
A division of the seminiferous epithelium into spermatogonia and Sertoli cells was found in a 1-year-old specimen. The interstitium, however, appears to remain undifferentiated until 2 years of age.
Curves depicting the history of each testicular cell type are shown. Cellular abundance stabilizes at adult levels by the time the testis reaches a weight of 700 g.
The pubertal period seems to involve approximately 4 years. The start of puberty is individually variable over an apparent range of 3 to 14 years of age. This broad pubertal span appears to be involved in variations of testis weights and testis- to body-weight ratios within the collection series.
The heaviest testis encountered in this study weighed approximately 2 kg. Based upon an earlier report, maximum testis weight in the African elephant probably approximates 4 kg. Comparative testis- to body-weight ratios for a variety of mammals indicate that elephant testes are small in relative terms.
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