The Manzanita Project
- Selected images of locally endangered species.
- http://www.calacademy.org/research/library/manzanita/html/selected.htm

California - San Francisco Garter Snake
- Environmental Impact on Endangered Animals - San Francisco Garter Snake (Thamnophis Sirtalis Tetrataenia).
- http://library.thinkquest.org/2878/ca_san_francisco_garter_snake.html