By Debbie "The Rat Lady" Ducommun
It's very difficult to hand raise a baby rat less than 2 weeks old. The best thing is to find a nursing rat to serve as a foster mother. As long as the babies are about the same age as her own, mother rats are almost always willing to adopt orphans. The best way to locate a foster mother is to contact local breeders or pet shops.
If a foster mother isn't available, the only alternative to save an orphan is to raise it yourself. When attempting to raise an infant rat, there are three elements to consider: warmth, hygiene, and diet. Until their fur grows in, baby rats can't regulate their own temperature. The best place to keep an orphaned rat is in a small box on a piece of felt large enough
to also form a blanket over the baby. Felt has no threads that can get wrapped around the baby's legs. Warmth can be supplied by either a hot water bottle, a lightbulb, or a heating pad. The important thing is to keep a thermometer next to the baby so you know exactly what temperature it is experiencing. Use a small weather thermometer, not a medical thermometer, as the latter can't record drops in temperature. Keep the temperature around 100-102 degrees F. Use heating pads with extreme care as they can get very hot. Use on the low setting only and place only one end of the box on the pad so the baby can crawl away from the heat if necessary. You may even have to put a towel between the pad and the box to keep it from getting too hot. At two weeks of age you can start gradually reducing the temperature.
Infant rats can't go to the bathroom by themselves. They're stimulated to go only when rubbed around the genitals and anus. This is so the mother can ingest the waste and keep the nest clean. Massage the rat's genital area with a warm damp cotton ball for several minutes before and after every meal to take care of this important hygiene matter. If you fail to do so, the rat will die of toxic poisoning from its own wastes. Also clean the baby of spilled food with a damp cotton ball after meals and give him a full massage after every meal just as its mother would lick it to stimulate its circulation and help it to grow.
Now comes the hard part: feeding the baby rat. I recommend using human soy baby formula. The nutritional requirements for rats are closer to that of humans than dogs or cats. Buy the powdered formula, because the liquid will quickly go bad. Follow the directions for mixing it for babies, but the first few feedings, dilute it more than usual to give the baby rat a chance to gradually get used to the diet. Most nursing bottles sold for orphaned animals have nipples too big for rats. You might be able to find a doll bottle that will work. You can try using a dropper, but it's easy to get too much in the rat's mouth at one time which can cause choking. One of the best methods is to use a tiny piece of rag and form a nipple from one corner. Start by dipping the "nipple" in the formula and squeezing drops into the baby's mouth. Once the baby starts sucking on the rag, you can drip formula little by little onto the rag with a dropper so you don't have to remove it from the baby's mouth. Sterilize the feeding equipment every morning in boiling water. Mixed formula can be refrigerated for 24 hours before you need to discard it. Warm only the amount of formula you need to feed by placing it in a small container sitting in a cup of warm water. Do not microwave the formula! Test the temperature of the formula on your wrist before feeding it. It may take a while to get the baby used to nursing on the new nipple and the new taste. Hold the baby upright with a tissue under its chin to catch spilled formula. Be careful not to give the baby too much formula at once, or it can choke, causing formula to come out its nose. Newborn rats normally nurse about every 2 to 3 hours. You'll need to feed your baby every 3 hours during the day and once in the middle of the night for the first week and every 4 hours the second week. Overfeeding can cause stomach upset. During the first week, stop the feeding session when you can see that the baby's stomach is full of white formula(it will show through the baby's translucent skin. Later, the baby will let you know when its had enough by turning away from the bottle.
The Weaning Process
When the baby is a week old it will start to get hair and may be ready to try slurping some baby cereal mixed with formula off your finger (mix it soupy). At two weeks of age, when its eyes open, most of your work will be done because the baby will be able to eat baby food and rodent blocks soaked in water. At
this age you can stop the night and bottle feedings and offer the formula mixed with baby cereal in a dish (jar lids work great.) By 3 weeks of age the rat will be eating mostly solid food, although it wouldn't be weaned yet, so you should still be offering some formula. At 4 weeks you can completely wean your baby and congratulate yourself on a job well done!