SENSES
Sight
Being nocturnal, vision is less important than hearing, olfaction, and sensation. The hamster has a panoramic visual field. A large orbital venous sinus is present and this is used for blood sampling in laboratory animals (Bivin et al.
1987).Hearing and touch
In common with all rodents, hamsters have large tympanic bullae giving them a keen sense of hearing (Fig. 11.4). Sensitive vibrissae are the main channel for somatic sensory input.
Taste
Hamsters dislike saline solutions but love sugary foods (Carpenter 1956). They will also show preference for ethanol, which unlike most other rodents they can metabolize well on account of their having two to three times more alcohol dehydrogenase in their liver than do rats. It is thought that this may have evolved due to the storage of fermentative grains hoarded underground in their burrow. This high tolerance to alcohol means that scientists have been unable to use the hamster as a model for alcohol-induced diseases (Newcomer et al. 1987).
Olfaction
Being nocturnal, hamsters have a keen sense of smell and this is enabled by the extensive olfactory epithelium in the caudal nasal cavity and the vomeronasal (Jacobson’s) organ.
Jacobson’s organ is a 7 mm long tubular structure that is located bilaterally in the rostroventral nasal septum and completely enclosed in a bony capsule. The cranial end communicates with the nasal cavity rostrally. The medial wall of the lumen is lined by sensory olfactory epithelium with the vomeronasal nerve lying just beneath. Caudally, it connects with olfactory receptors lying in the ethmoturbinates (Bivin et al. 1987). This organ may play a role in pheromone behavior as well as olfaction as removal of the main and accessory olfactory bulbs completely removes sexual behavior (Bivin et al. 1987).