Studies of 399 cottontails (Sylvilagus floridanus mearnsii) taken during the winter and spring of 1958 through 1961 have established the early portion of the breeding season for the species in Iowa. Males attained breeding condition starting in February. Pregnant females occurred late in February. Most females became pregnant for the first time in March. All females examined after April 1 were pregnant. Differences in commencement of the breeding season from one year to another were noted. A statistically significant difference in average size of first and second embryonic litters was noted. Litters from northern Iowa averaged larger than those from southern Iowa. This difference was statistically significant at the 0.20 level of confidence.
Proceedings of the Iowa Academy of Science
©1962 Iowa Academy of Science, Inc.
Kline, Paul D.
"Vernal Breeding of Cottontails in Iowa,"
Proceedings of the Iowa Academy of Science, 69(1), 244-252.
Available at: https://scholarworks.uni.edu/pias/vol69/iss1/41