Animales Exoticos

MEDICINE OF SMALL PET RODENTS

R. Avery Bennett, DVM, MS, Diplomate ACVS

University of Florida, College of Veterinary Medicine, Gainesville, FL

HAMSTERS

CLASSIFICATION

Order Rodentia, Family Cricetidae

Mesocricetus auratus - Golden or Syrian hamster

Cricetus cricetus - European hamster

Cricetulus griseus - Chinese hamster

All hamsters sold as pets are descended from 1 male and 2 female siblings which were captured in 1930. Color varieties include wild type, cinnamon, cream, white, piebald, and long haired teddy bears.

HUSBANDRY AND NUTRITION

Hamsters do well on a pelleted rodent diet. Because they have a blunter nose than other rodents, they may not be able to eat through wire or slotted food hoppers.

Hamsters should be provided with a deep layer of wood shavings as bedding. They are great chewers and escape artists. They are primarily nocturnal but do have brief periods of daytime activity. Of the rodents commonly kept as pets they tend to be the most pugnacious but usually only bite after being roughly handled or surprised. Hamsters are solitary animals and prefer to be caged alone. Females will attack males unless they are introduced during the sexually receptive time. Hamsters of the same sex may be housed together but fighting may still be a problem. When temperature and day length decrease, hamsters "pseudohibernate". During this period they gather and store food and become relatively inactive. Hamsters are very good at escaping and do not return to their cages as rats and gerbils do. Hamsters life span is 1.5-2 years. The short life span and their mean behaviors make hamsters my least recommended rodent pet.

RESTRAINT

Though hamsters are not naturally aggressive, they will bite and may feign biting. Hamsters may be picked up by getting them to enter a small can or by cupping them in the hands. When restrained, the scruff of the neck is grasped and the excess skin is gathered in the hand so that the hamster can not turn around in its skin and bite the holder.

OTHER DATA

Life span - 1.5-2 yrs

Body weight - 80-130 g (m); 95-150 g (f)

Body temperature - 98.5-100.5oF

Respiratory rate - 35-135/min

Heart rate - 250-500 bpm Blood volume - 78 ml/kg

BLOOD COLLECTION - Orbital sinus, toenail clip, and cardiac puncture may be used.

REPRODUCTION

Males - The testicles of adult males can be exposed by applying gentle pressure to the abdomen. The scrotum gives the rump of the male a more rounded appearance compared to the more pointed female's. Males have a greater anogenital distance and a pointed genital papilla with a round opening when compared with females.

Females - Hamsters become sexually mature at 32-42 days age. Except for a few hours of the 4 day estrus cycle the female is unreceptive and will attack an introduced male. As estrus approaches, a thin, stringy translucent mucus discharge can be drawn from the vulva. On the morning following estrus an opaque thick stringy mucous is present. A receptive approach toward a male in the early evening indicates the time is right. The male should be removed after copulation also. The gestation period is 15.5-16 days. Litter size is 5-9. Pseudopregnancy does occur occasionally. Nesting materials such as tissue paper should be provided a few days prior to parturition. Hamsters have a non-fertile post-partum estrus and a fertile estrus 2-18 days post-weaning.

Pups - Litter abandonment and cannibalism are common during the first pregnancy and during the first week post-partum. Because of this, the nest should not be disturbed and the pups should not be handled for the first week. It is best to put a week's food and bedding in at 13 days post-mating so the mother need not be disturbed during the first week. Young are usually weaned at 20-25 days age.

TEETH - Hamsters have 2 continually growing upper and lower incisors and 3 permanent upper and lower molars. Overgrowth is usually a sequel to malocclusion. Mice, rats, and gerbils have the same dentition.

GERBILS

The Mongolian gerbil - Order Rodentia, Family Cricetidae, Meriones unguiculatus. Gerbils are usually agouti but black, white, dove, piebald, and cinnamon colors are also available.

HUSBANDRY AND NUTRITION

Gerbils are active, burrowing social animals with cycles of activity during the day and the night. They are relatively odorless desert animals and rarely bite. Gerbils are more inquisitive than other rodent pets. They are social and live well in groups. However, an established group may be aggressive toward a newcomer. About 50% of gerbils develop epileptiform seizures which may be precipitated by excitement, noise, handling, a new environment, or other stresses.

Gerbils are active chewers and cages should be designed to prevent escape. They should be lined with a deep layer of bedding to allow burrowing. A balanced high protein rodent diet should be fed through a feed hopper. Though they are a desert species, clean water should always be available.

RESTRAINT

Gerbils may be picked up by the base of the tail and placed in the hand. They may the be grabbed over the back with the first 2

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