A tale of two mice: A trans-Holocene record of Peromyscus nesodytes and Peromyscus maniculatus at Daisy Cave, San Miguel Island, California

Abstract

Rats and mice are among the most successful mammals on earth, with some of these species thriving in and around human settlements or areas disturbed by human activities. Here, we present morphological, taphonomic, and chronological data on two mice ( Peromyscus nesodytes [extinct] and P. maniculatus [extant]) from a trans-Holocene sequence at Daisy Cave, San Miguel Island, California. We explore the colonization history of each species, species abundance through time, taphonomic history, and the causes and timing of the extinction of P. nesodytes. P. maniculatus were probably introduced by humans to San Miguel Island ~11,000 years ago, 1000 years earlier than previous estimates, and P. nesodytes does not occur in Daisy Cave deposits after ~8000 years ago, some 7000 years earlier than reported at adjacent Cave of the Chimneys. Island P. maniculatus form a distinct morphological group from all other North American subspecies. These data highlight the importance of morphological analyses of archaeological and subfossil rodent specimens for understanding the evolution and natural history of island endemic species and their interactions with humans.