The Hamster

I. Origin of the Hamster.- 1 History of the Capture and Domestication of the Syrian Golden Hamster (Mesocricetus auratus Waterhouse).- 1. Introduction.- 2. The Early Years: Discovery and Description.- 3. On the Road to Jerusalem: Capture and Breeding.- 4. The Invasion of America: Dissemination and Proliferation.- 5. New Genes on the Line: A Reconnaissance Expedition to Aleppo.- 6. Conclusion.- References.- II. Reproductive Endocrinology.- 2 The Estrous Cycle.- 1. Introduction.- 2. Sexual Maturation-The First Estrous Cycle.- 2.1. The Ovary.- 2.2. The Pituitary.- 2.3. The Brain.- 3. Follicle Maturation and Ovulation.- 3.1. Time of Ovulation.- 3.2. Ovarian Steroids and Ovulation.- 3.3. Role of the Nervous System in Ovulation.- 3.4. Linkage of Sexual Receptivity with Ovulation.- 4. The Luteal Phase.- 4. 1. Pseudopregnancy.- 5. Seasonal Anestrus.- 6. Conclusions.- References.- 3 Endocrinology of the Pregnant Hamster.- 1. Copulatory Behavior in the Estrous Hamster.- 2. Pseudopregnancy in the Hamster.- 3. Pregnancy in the Hamster-General Considerations.- 3.1. Fetal, Placental, and Ovarian Weights.- 3.2. Number of Follicles Greater than 4l5? in Diameter.- 3.3. Induction of Ovulation in the Pregnant Hamster by 20 IU HCG.- 3.4. Growth and Regression of the Corpus Luteum.- 4. Peripheral Steroid and Peptide Serum Hormone Levels in the Pregnant Hamster.- 4.1. Progestins.- 4.2. Estrogens.- 5. Peptide Hormones during Hamster Pregnancy.- 6. Luteotropic Complex of the Pregnant Hamster.- References.- 4 Male Hamster Reproductive Endocrinology.- 1. Sexual Maturation.- 2. Endocrine Function in the Adult Male.- 3. Aging.- 4. Seasonal Changes.- 4.1. Photoperiod-induced Testicular Regression.- 4.2. Photoperiod-induced and Spontaneous Testicular Recrudescence.- 4.3. Hormonal Mechanisms of Seasonal Changes in Reproductive Function.- 5. Typical Hormone Values.- References.- 5 Pineal-Reproductive Interactions.- 1. Introduction.- 2. Pineal Morphology.- 3. Pineal Melatonin Synthesis.- 3.1. Photoperiodic Influences.- 3.2. Endocrine Influences.- 3.3. Influence of Age.- 4. Photoperiod, Pineal, and Reproduction.- 4.1. Males.- 4.2. Females.- 5. Pineal Hormones.- 5.1. Indoles.- 5.2. Polypeptides.- 6. Pineal and Seasonal Reproduction.- 6.1. Inhibition Phase.- 6.2. Sexually Quiescent Phase.- 6.3. Restoration Phase.- 6.4. Sexually Active Phase.- 7. Melatonin and the Seasonal Reproductive Cycle.- 8. Sites of Action of Pineal Hormones.- 8. 1. Neuroendocrine Axis.- 8.2. Gonads and Accessory Sex Glands.- 9. Concluding Remarks.- References.- III. Social Behaviors.- 6 Communication.- 1. Introduction.- 2. Postures Used during Social Interactions.- 2.1. Do the Dark Chest Bars Have a Communicatory Significance?.- 3. Auditory Communication.- 3.1. Sonic Signals.- 3.2. Ultrasonic Calling and Communication.- 3.3. Ultrasounds and Echolocation.- 4. Chemical Communication: Scent Signals and Scent Marking.- 4.1. Flank Glands and Flank Marking.- 4.2. Vaginal Secretions and Vaginal Marking.- 4.3. The Harderian Gland.- 4.4. Other Glands, Other Marking Behaviors.- 5. Functions of Scent Signals.- 5.1. Species Recognition.- 5.2. Sexual Recognition and Attraction.- 5.3. Reproductive State of Females.- 5.4. Sexual Arousal and Aphrodisiac Odors.- 5.5. Discrimination of Individuals.- 5.6. Defense of the Home Burrow.- 6. Directions for Future Research.- 6.1. Interaction of Signals.- 6.2. Neural and Neuroendocrine Mechanisms.- 6.3. Development of Responses to Olfactory Signals and the Related Neural Substrates.- 6.4. Comparative studies.- References.- 7 Sexual Differentiation and Development.- 1. Introduction.- 2. Morphological Differentiation.- 2.1. Differentiation of the Gonad.- 2.2. Ductal Differentiation.- 2.3. Brain Differentiation.- 2.4. Sexual Dimorphism in Reproductive Parameters.- 2.5. Sex Ratio.- 3. Maturation of Sexual Behavior.- 3.1. The Female.- 3.2. The Male.- 4. Behavioral Differentiation.- 4.1. Sexual Behavior.- 4.2. Aggressive Behavior.- 4.3. Parental Behavior.- 5. Summary and Conclusions.- References.- 8 Female Sexual Behavior.- 1. The Description of Female Sexual Behavior.- 2. Precopulatory Behaviors.- 3. Lordosis.- 4. Hormonal Factors Inducing Estrus.- 5. Factors Regulating the Duration of Female Sexual Receptivity.- 6. The Effects of Copulatory Stimuli on Female Behavior.- 7. Summary and Discussion.- References.- 9 Male Sexual Behavior.- 1. Introduction.- 2. Ontogeny.- 3. Description of Male Copulatory Behavior.- 4. Effects of Castration.- 5. Hormone Replacement.- 5.1. Testosterone.- 5.2. Androstenedione.- 5.3. Dihydrotestosterone.- 5.4. Estrogen, Progesterone, and Hormone Combinations.- 6. Induction of Female Sexual Behavior.- 6.1. Estrogen.- 6.2. Progesterone.- 6.3. Androgens.- 7. Effects of Mating.- 8. Pharmacological Effects.- 9. Aging.- References.- 10 Parental Behavior.- 1. Introduction.- 2. Chapter Objectives.- 3. Theoretical Framework.- 4. Pregnancy.- 4.1. Nest Building.- 4.2. Sexual Receptivity.- 4.3. Aggression.- 4.4. Maternal Responsiveness during Pregnancy.- 5. Parturition.- 6. The Postpartum Period.- 6.1. Postpartum Cannibalism.- 6.2. Maintenance of Mother-Litter Bond.- 6.3. Mother-Litter Synchrony.- 6.4. Maternal Aggression.- 6.5. Weaning.- 7. The Transition Phase.- 8. Responses of Maternally Naive Hamsters To Pups.- 8.1. Sensitization.- 8.2. Role of Sensitization.- 9. Conclusions And Future Directions.- References.- 11 Neural Basis of Reproductive Behavior.- 1. Introduction.- 2. Male Sexual Behavior.- 2. 1. Olfactory Systems.- 2.2. Forebrain-Hypothalamus.- 2.3. Summary.- 3. Female Sexual Behavior.- 3.1. Lordosis.- 3.2. Ultrasonic Vocalizations.- 4. Maternal Behavior.- 4. 1. Olfactory Systems.- 4.2. Forebrain-Hypothalamus.- 4.3. Summary.- 5. Conclusions.- 5.1. Male Mating.- 5.2. Female Sexual Behaviors.- 5.3. Maternal Behaviors.- References.- 12 Aggressive Behavior.- 1. Introduction.- 2. Behavioral Descriptions.- 3. Methodological Considerations.- 3. 1. Sex of the Opponents.- 3.2. Housing Conditions.- 3.3. Body Weight.- 3.4. Age.- 3.5. Other Subject Variables.- 3.6. Test Cage.- 3.7. Other Test Condition Variables.- 3.8. Measures of Aggression.- 4. Hormonal Effects: Female.- 4.1. Estrous Cycle.- 4.2. Ovariectomy and Estrogen and Progesterone.- 4.3. Testosterone.- 4.4. Other Hormones.- 4.5. Pregnancy and Lactation.- 5. Hormonal Effects: Male.- 5.1. Castration and Androgens.- 5.2. Estrogen and Progesterone.- 5.3. Other Hormones.- 6. Neural Basis.- 6.1. Limbic System.- 6.2. Olfaction.- 7. Peripheral Influences.- 7.1. Flank Gland.- 7.2. Vaginal Discharge.- 7.3. Urine.- 7.4. Chest Patches.- 7.5. Harderian Gland.- 8. Conclusions.- References.- IV. Development and Individual Function.- 13 Behavioral Development in the Syrian Golden Hamster.- 1. Introduction.- 2. Sensory and Motor Behaviors.- 2.1. Olfaction.- 2.2. Vision.- 2.3. Other Senses.- 2.4. Activity and Movement.- 3. Maintenance Behaviors.- 3.1. Thermoregulation.- 3.2. Ingestion.- 3.3. Waste Elimination.- 3.4. Grooming.- 4. The Family Group as a Special Feature of Hamster Development.- 4.1. Affiliative Behavior in Social Isolates.- 4.2. Early Family Relationships.- 4.3. Dissolution of the Family Group.- 4.4. Effect of Early Social Isolation.- 5. The Impact of a Brief Gestation: Is the Newborn Golden Hamster Pup "Immature" for its Age?.- 6. Summary and Conclusions.- References.- 14 Biological Rhythms.- 1. Circadian Rhythmicity and Regulation by Light.- 1.1. Entrainment and Phase Response Curves.- 1.2. Aftereffects.- 1.3. Phase Shifts and Transients.- 1.4. Masking.- 1.5. Activity and Rest Phases.- 1.6. Splitting.- 2. Chemical and Temperature Control of Circadian Rhythmicity.- 3. Neural Control.- 3.1. Photoperiodism.- 4. Other Rhythms.- 4.1. Reproductive Activity.- 4.2. Drinking.- 4.3. Body Temperature.- 4.4. Feeding.- 4.5. Aggression.- 4.6. Other Rhythms.- 5. Summary and Future Directions.- References.- 15 Regulation of Energy Balance in the Golden Hamster.- 1. Anatomy and Physiology of Hamster Gastrointestinal Tract.- 1.1. Stomach.- 1.2. Intestine.- 1.3. Cecum.- 1.4. Liver and Gallbladder.- 1.5. Pancreas.- 1.6. Synopsis.- 2. Endocrine Influences on Somatic Growth, Body Fat, and Feeding in the Golden Hamster.- 2.1. Insulin.- 2.2. Growth Hormone.- 2.3. Prolactin.- 2.4. Gonadal Hormones.- 2.5. Thyroid and Adrenal Hormones.- 2.6. Synopsis.- 3. Physiological and Behavioral Responses of Hamsters to Signs of Impending and Actual Disturbances in Energy Balance.- 3.1. Photoperiod.- 3.2. Ambient Temperature.- 3.3. Fast and Glucoprivation.- 3.4. Physical Activity.- 3.5. Variable Caloric Density and Texture of Food.- 3.6. Synopsis.- 4. Brain Mechanisms in Hamster Energy Regulation.- 4. 1. Weight Gain, Feeding, Hoarding, Nest Building, and Spontaneous Activity.- 4.2. Weight Loss, Anorexia, and Somnolence.- 4.3. Neurochemistry and Pharmacology of Feeding and Weight Regulation in Hamsters.- 4.4. Synopsis.- References.- 16 Visual and Somatosensory Processes.- 1. Uses of Vision in the Hamster.- 1.1. Visual Development and the Role of Visual Experience.- 2. Anatomy and Physiology of the Hamster Visual System.- 2.1. The Retina.- 2.2. Superior Colliculus.- 2.3. Thalamocortical Organization of Vision and Somesthesis.- 3. Summary.- 3.1. The Hamster Visual System as a "Simple System".- 3.2. Niche-specific Adaptations.- References.- Appendix: Characteristics of Mesocricetus auratus.