Reproduction for the California Meadow Vole can occur year round with a general breeding season that ranges from 270 to 320 days that is most common during the months of March through April. This breeding season is likely brought on by interactions with environmental and social cues while the end of the season may be due to a lack of water (Cudworth and Koprowski 2010). Microtus californicus appear to exhibit monogamous relationships with mates when population sizes are small. Denser populations will sometimes exhibit polygamous traits and will breed with multiple partners (ADW 2002). This is known as being “socially moderate,” where it is a midway between the two behaviors. It is most common for male voles to pursue females into mating but rare instances have been discovered where the female will pursue a male (Cudworth and Koprowski 2010).

                Ovulation in females occurs after copulation within 15 hours after mating. Pregnancy can be achieved after only one round of copulation but multiple rounds are usually necessary. Once pregnant, the gestation period for M. californicus is roughly three weeks, more specifically 22 days.  As soon as fifteen hours after birth, females can mate again. Litter sizes are variable, producing anywhere from 1 to 11 young, but averaging 4 to 5 (ADW 2002). Females can have several litters over the course of their lifetime.

                Young are born blind, deaf, and lack fur and pigment however their eyes can sense light. The auditory function occurs in the wild as soon as 5 days and the eyes begin to open after 9 days. An average mass for newborns is 2.8 grams but they grow quickly. Juveniles go through several stages of pelage molts, or shedding of fur,  until they obtain their adult coat. M. californicus have been observed to display more parental care to their young than other species. Both sexes brood their young together participating in duties such as sitting on the nest, manipulating nest materials, along with licking and retrieving pups. The young pups are weaned from their parents at two weeks of age. Females reach sexual maturity before males do (Cudworth and Koprowski 2010).

Next, read out the Interactions of the California Meadow Vole.