|Robust cottontail range|
The robust cottontail or Davis Mountains cottontail (Sylvilagus robustus) is a species of cottontail rabbit endemic to four mountain ranges in the southwestern United States and adjacent Mexico. It was long considered to be a subspecies of the Eastern Cottontail (S. floridanus), but has recently been promoted to species level due to morphological analysis.  Genetic data have confirmed the uniqueness of S. robustus.  S. robustus and the subspecies of S. floridanus are distinguished primarily by size, dental, and cranial differences. These rabbits typically average a total length of 42 cm, and weigh between 1.3 and 1.8 kg. This species is restricted to dry, brushy, mountains above 1500 meters. Despite its rarity, currently no governmental agency provides protection or listing for this species.
Historically, this species was known to be endemic to four mountain ranges. In Texas it was known in the Guadalupe Mountains, Davis Mountains and Chisos Mountains. In New Mexico it was known from the Guadalupe Mountains. And in Coahuila, Mexico it is known from the Sierra de la Madera. It is believed to be extirpated from the Chisos and Guadalupe Mountains.
- Ruedas, L. & Smith, A.T. (2009). "Sylvilagus robustus". IUCN Red List of Threatened Species. Version 2009.1. International Union for Conservation of Nature. Retrieved 2009-08-20. Database entry includes a brief justification of why this species is endangered
- Systematics of Sylvilagus Gray, 1867 (Lagomorpha: Leporidae) from Southwestern North America. Luis A. Ruedas. Journal of Mammalogy, Vol. 79, No. 4 (November 1998), pp. 1355-1378.
- Lee, DE; Pfau RS; Ammerman LK (2010). "Taxonomic status of the Davis Mountains Cottontail, Sylvilagus robustus, revealed by amplified fragment length polymorphism". Journal of Mammalogy.
- The mammals of Texas: 2nd edition By David J. Schmidly, William B. Davis. 2004. pp. 466-467. University of Texas Press.