Groups of up to 500 have been observed in California. Both sexes may roost together in the non-breeding season, but roost separately during spring and summer. Copulation occurs from September to November. Delayed implantation is followed by births from May to June. The single litter has 1 young.
Twins are rare.
The precocial young suckle for 1 mo. No longer occurs in coastal regions, and most records currently are from mountain ranges bordering the Colorado River. Species No. 1. Arnold, L. W. 1943. California winter records of Macrotus californicus Baird.