Influence of Season on Reproductive Characteristics of Woodchucks in Virginia

Reproductive characteristics of110 woodchucks (Marmota monax) were examined between 13 March and 30 November in 1974 and 1975. Ovulation rates averaged 4.73 in adult females examined between March to June. Less than 50 percent of yearlings ovulated during this period compared to 100 percent of adults. Preimplantation loss of embryos averaged 0.5 per pregnancy. Corpora lutea persisted until August in one female but was a reliable indicator of ovulation only until July. Placental scars persisted until September in one female. The peak of spermatogenesis seemed to occur earlier in adult males than in yearlings. Spermatogenesis were ceased in all males before June.