Growth and development of the western harvest mouse, Reithrodontomys megalotis megalotis

• Main Author: Richins, Gary H.
• Format: Others
• Published: BYU ScholarsArchive 1973
• Subjects: Mice
• Online Access: https://scholarsarchive.byu.edu/etd/7859; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=8859&context=etd

Growth rates, gestation period, litter size, reproductive age, sex ratios, and development were studied on 198 litters of Reithrodontomys megalotis megalotis. Growth was characterized by several standard skull and body measurements, and was partitioned into four phases of 1-3, 4-12, 13-22, and 23-70 days. Growth was best described by measurements of tail length, ear length, and dried eye lens weight. Reproductive activity began as early as 38 days for females and 59 days for males. Gestation period was 22 days and mean litter size was 3.83 (range 1-7). Sex ratio was 53.49% males to 46.51% females. Reproductive efficiency was 53.53%. The development of R. m. megalotis was very similar to that of R. m. dychei. Early breeding, post-partum estrous, year-round breeding, high reproductive efficiency, and a short gestation period contribute to a high reproductive potential in R. m. megalotis.