The golden hamster has a compartmentalized stomach consisting of a forestomach and a glandular stomach. The forestomach is lined with keratinized epithelium and contains an active microbiol population capable of significant cellulolytic activity. This organ is not essential for life and is the first entrance point for swallowed feed. The hamster, while having a protein requirement like that of the rat, utilizes protein much differently. It ranks soybean meal above a fish protein concentrate and does not utilize added crystalline essential amino acids as such. Acceptance of the hamster as a nutritional surrogate of the rat seems unwarranted.