Pequeña culebra de no mas de 30 cm de largo tomando el sol en las vias del tren.
Ratoncitos de hábitos nocturnos a los 4780msnm en el Parque Nacional Iztaccíhuatl-Popocatépetl
This species of mouse is abundant on rocky cliffs and boulders at around 5700' elevation and higher.
I have not identified this to species but think it is either the brush mouse, Peromyscus boylei, or maybe more likely, the white-ankled mouse, P. pectoralis, both of which occur in the habitat (DeBaca and Jones, Report on the mammals of the Davis Mountains Preserve, unpubl.)
The Cricetidae are a family of rodents in the large and complex superfamily Muroidea. It includes true hamsters, voles, lemmings, and New World rats and mice. At almost 600 species, it is the second largest family of mammals, and has members throughout the New World, Asia, and Europe.