Charina bottae

The Society for the Study of Amphibians and Reptiles (Nicholson 2025) recognizes a single species with two subspecies, the Northern Rubber Boa Charina bottae bottae and the Southern Rubber Boa C. b. umbratica. Previously, Rodríguez-Robles et al. (2001) concluded that C. b. umbratica should be elevated to a full species distinct from C. b. bottae and this was adopted by Crother (2017). According to Nicholson (2025), "Based on morphological data from hundreds of additional specimens, Hoyer et al. (2019) expanded the geographical distribution of C. umbratica, which was corroborated by Grismer et al. (2022) using a genome-wide SNP dataset. Grismer et al. (op. cit.) found that C. umbratica was morphologically distinct from C. bottae, but recognizing umbratica as a full species would make bottae paraphyletic. Additionally, they found that C. umbratica was composed of several distinct lineages occurring in sky islands across southern California. The authors recognized umbratica at least as a subspecies in the interest of having it as a recognized taxon listed under the Federal Endangered Species Act." Both Hoyer et al. (2019) and Grismer et al. (2022) noted additional taxonomic research is needed.

This species is widespread in western North America and is locally common in suitable habitat. The population has been in decline due to habitat loss, collection, and variety of types of habitat degradation. The species continues to be threatened by habitat loss, habitat degradation, and the loss of habitat suitability due to climate change.

The range extends from southern British Columbia and Alberta, Canada, south to west-central California (probably southward to San Luis Obispo County), central Nevada, and southern Utah, from the Pacific coast east to north-central Wyoming and western Montana, USA, from near sea level to about 3,050 meters (10,000 feet) (Stewart 1977, Stebbins 2003, Pearson 2010, Reynolds and Henderson 2018). Distribution is spotty in many areas, particularly at the southern and eastern fringes of the range. Charina populations in the southern Sierra Nevada, Tehachapi Mountains, and on Mt. Pinos, Mt. Abel, Mt. Alamo, and Frazier Mountain are of uncertain taxonomic status.They have some umbratica characteristics but based on mtDNA data were included in the C. bottae (northern rubber boa) clade by Rodriguez-Robles et al. (2001), whereas Stebbins and McGinnis (2012) assigned these populations to C. umbratica. Using Global Biodiversity Information Facility (GBIF) (2026) records, range extent is estimated to be 2 million km² (RARECAT 2025).

This species is represented by many occurrences or subpopulations. For example, Stewart (1977) mapped over 200 collection sites rangewide.

This species is not threatened in most of the range, however, some sub-populations may be impacted by habitat degradation due to agriculture, urban development, forest management practices, recreation (mainly off-road vehicle use), rock formation (hibernacula/shelter) disturbance by collectors and hobbyists, habitat drying due to increased drought, wildfire, and temperature associated with climate change, mortality from road crossings, and fuel wood harvesting (USFWS 2021). By 2100, 43% of rubber boa habitat is projected to become unsuitable due to climate change (Pilliod et al. 2024).