HAMSTER Hamsters have cheek pouches used to transport and store food and to conceal a newborn litter when danger is present. Hamsters have hip glands, which are dark raised spots located on either flank or hip area. These glands secrete material used to mark its territory. These glands should not be confused with tumors. The life span is relatively short, 18-24 months and usually the males live longer than the females. Sexual maturity occurs at 6-8 weeks of life with pregnancy lasting 15 days. Litter size is 6-8 pups. Newborns are hairless, blind and have closed ears. Hair begins to grow at 8 days of age, pups can eat solid food at 7-10 days of age, eyes open at 1-15 days old and weaning is complete at 21-25 days old. Lack of experience in first time mothers and environmental disturbances may cause a hamster to eat its newborns. Diet: The natural diet consists of seeds and plant materials, however as pets, hamsters do very well on a pelleted diet or rodent chow formulated for rats and mice. A seed or a seed/dried- vegetable mix, should not be fed as the primary diet but is fine as a treat. Fresh vegetables can be fed in small amounts. Greens fed in small quantities. Sudden dietary changes may result in intestinal upsets and diarrhea which can be severe and may result in death of the pet. Hamsters carry food in their cheek pouches causing the pouches on either side of the face to bulge. They also hide food in their nest to eat at a later time. Housing: Wire cages, aquariums and plastic habitats (Habitrails) may be used for a home for your hamsters. Each cage should provide a safe escape proof home for your pet. Doors and tops should be well secured to prevent escape. The cage should be well ventilated to allow flow of fresh air to help prevent the build up of odor from urine, feces and spoiled food. Most hamsters will drink from a water bottle secured to the side of the cage with a lick spout to drink and to reduce spillage. The food bowl and water bottle should be cleaned daily and fresh food and water should be supplied daily. Cages should be cleaned at least on a weekly basis. Depending on the size of the cage and the number of hamsters housed in the cage, it may need to be cleaned more frequently. If the cage has an odor of urine or feces then it needs to be cleaned. Constant exposure of your pet to unsanitary conditions is unpleasant for the pet and can result in infections of the skin, eyes and respiratory tract. Dilute chorine bleach (1 part bleach to 10 parts water), is effective for sanitizing a cage. After cleaning with bleach solution, the cage should be rinsed thoroughly to remove all bleach residue. Do not use cedar or pine shavings as bedding. These woods contain aromatic oils that are very irritating to the skin and mucous membranes of the eyes, nose, throat and lungs. Safe bedding materials include recycled newspaper bedding, aspen shavings, hay and plain white unscented toilet paper or paper towels. Behavior: Hamsters are nocturnal (active at night) and may bite if awakened suddenly. Hamsters do not have good eyesight therefore the owner should always speak to the hamster before picking it up. This gives the hamster some warning that it is going to be touched and reduces the likelihood of you being bitten. The approach from above often triggers a defensive response. The hamster may flip onto its back and try to bite. The teeth are needle like and the bite can be painful, especially to a child. To pick up your hamster, cup your hands around it. Some will nip when picked up no matter what. In these cases, you can use a paper-towel tubes to slide over the hamster, then slide the hamster out the other end onto your hand. Hamsters are nocturnal animals which means they spend a lot of their daylight time sleeping and are more active at night. They enjoy running on an exercise wheel or you may use the clear plastic exercise balls sold for this purpose. Part 1:Handling and restraining hamster 1. Remove the hamster from the cage by allowing it to climb into a small cup or container. Coax it onto a flat surface.(Avoid surprising the hamster.) 2. Approach the hamster from behind and place a hand palm down over the hamster with the thumb near the head. 3. Close the hand slowly and grasp the loose skin over the neck and back, bunching it securely in the hand and pulling the skin taut over the thorax and abdomen.(Grasping more skin lessens the struggle and results in a more secure hamster.) 4. Lift the animal using the same hand to support the body of the hamster (Fig. 1.3.3). 5. Observe or inject the restrained hamster. Figure 1 Hamster handling and manual restraint. Place hand palm down over hamster (A). Grasp the loose skin over the neck and back, pulling the skin taut over the thorax and abdomen (B). Part 2: Injection and blood collection Below are peripheral vessels that are commonly accessed for blood collection or fluid administration. Recommended needle sizes are 23 to 27 gauge. Larger needles may be necessary for injecting large volumes or viscous materials. Vessels Comments Lateral saphenous vein (lateral tarsal 1. Accessing the lateral saphenous vein: vein) o Does not require anesthesia. o May be aided by sedation because vein visibility is enhanced by peripheral vasodilation (drug effect). o May be aided by sedation to reduce animal struggling due to distress. 2. Blood collection from the lateral saphenous vein does not involve cannulation of the vein lumen. Instead, the vein is punctured percutaneously and blood is passively collected as it pools on the skin. Jugular vein Performed under anesthesia because of restraint method and the need for animal immobilization. Cardiac puncture 1. These two methods require anesthesia. Carotid artery 2. Most often allowed only as a terminal procedure. 3. Check with your institution for guidelines on these routes of blood collection. Abdominal vena cava 1. Performed as a terminal procedure under Abdominal aorta anesthesia. 2. Vessel access involves a ventral midline incision and reflection of intestines. Retroorbital sinus 1. Retroorbital puncture is controversial because of the risk of injury to the optic nerve and other nearby structures. 2. This method is considered to be painful and may cause blindness. 3. Generally requires anesthesia. 4. Topical ophthalmic anesthetic is recommended post-procedure. Below are the nonvascular routes of injection that are commonly used in hamsters. Included are volume recommendations for the safe administration of fluids acutely in adults ( hamster, average 120 g). Recommended needle sizes are 23 to 27 gauge; larger needles may be necessary for injecting viscous materials. Subcutaneous (SQ or SC) - 3-4 ml in scruff Intraperitoneal (IP) - 3-4 ml Oral (PO) - 20 ml/kg Intradermal (ID) - 0.05 ml/site Intramuscular (IM) - 0.1 ml per site Cheek pouch - 0.1 ml instilled into wall of everted pouch. Volume recommendations for intravenous fluid administration and blood collection in adult hamsters: IV fluid volume Tot. blood volume Safe bleed volume Bleed-out volume (ml) (ml) (ml)a (ml)b max. acute admin. 0.3 ml 78 ml/kg 0.55 ml 2.9-5.2 ml Removing greater quantities of blood (exceeding 10% of total blood volume) can produce hypovolemic shock. Repeated collections of smaller amounts of blood will have the same effect. In such procedures, animals should receive warmed, physiological fluids to replace the volume of blood collected. In addition, monitor the animal’s hematocrit for anemia. Animals should be exsanguinated only under anesthesia.