New record of leucism in the North American opossum (Didelphis virginiana) from Mexico

Leucism in Didelphis virginiana

Abstract

Presence or absence of melanin determine pigmentation and color pattern in mammals. Excess or deficit of melanin production generates coloration anomalies, one of the most common is leucism. Leucistic mammals have total or partial absence of pigmentation in the body except for maintaining eye color. The North American opossum, Didelphis virginiana, is a widely distributed marsupial present in northern and central America and that have adapted well to urban environments. Recently, the first record of leucism in the North American opossum was reported from Quintana Roo, Mexico. We perform wildlife rescue in the Guadalajara Metropolitan Area as part of the activities of the Tlajomulco de Zúñiga’s Wildlife Rescue Unit. This unit receives daily reports of wildlife in urban areas. On June 17, 2025, we received a call regarding a young D. virginiana wandering in the street. Herein we present the second record of leucism in D. virginiana, a young female from the Guadalajara Metropolitan Area in Jalisco. The individual was found in an urban environment and had signs of errant behavior and blindness. Although presence of this species in the region is common, living in urban areas could be a challenge and may cause genetic and nutritional problems that could be responsible for the coloration anomaly, affecting directly the individual’s survival. This record is the starting point of further research that can help us use wild mammals as bioindicators and generate local conservation strategies for urban wildlife.