You fell in love with a cuddly little baby teddy bear hamster at the pet store...so it was probably a shock to realize your new furbaby is about to have babies of her own. This is a common discovery for new hamster owners. You need to be aware of a few basic Syrian hamster facts to get Mom and babies safely through gestation, birth and the first few weeks of life.
The Syrian or Golden Hamster
The first thing you need to know is what kind of hamster you actually have. This is pretty important because Syrian and dwarf hamsters—the only types you'll find in a pet store—are different species with different gestation and different needs. Luckily, telling the difference is pretty easy: if your pet was called anything besides "dwarf hamster," you have a Syrian hamster. Syrians are also commonly called golden or teddy bear hamsters, or just plain hamsters.
Syrian hamsters are extremely solitary animals. They evolved in a harsh desert, have ranges that cover up to a square mile each and will attack and kill each other at a moment's notice. The female tolerates the male for only around 20 minutes while mating, and tolerates her own young for only about two months. With these restrictions on family life and romance, how do so many coexist in one cage at the pet store and how did your new friend end up in the family way?
How This Happens
The baby hamsters you see peacefully cohabiting in pet stores are all under 8 weeks old. However, these little balls of fluff can reproduce by the time they turn 4 weeks old and they go into heat every three to four days. They're also not picky—getting it on with close relatives doesn't bother them one bit. (In fact, they're all descended from only four siblings caught in 1930.) Combine these facts and a majority of female hamsters are pregnant before they even leave the pet store for their forever homes. Alternately, you may have gotten two hamsters so they could keep each other company—something they'll object to violently when they're over 8 weeks old. In the meantime, it turns out your "two girls" or "two boys" are actually one of each and you're about to have a whole lot more hamsters.
Hamster pregnancy lasts from 14 to 18 days—most give birth 16 days after doing the deed. Hamsters have a dual uterus (bicornate or "two-horned" uterus) and double vagina. The eggs and sperm meet near the ovaries and travel into the uterine horns on day three following fertilization. The embryos implant by burrowing into the uterine lining late in the morning of day three. This is when you'll see your mom hamster's behavior start to change as she begins gathering materials to build her nest. All of the fetuses' limbs and organs are present by day eight. The last five and a half days of pregnancy, days 10 to 16 or so, are the most active ones for the unborn hamsters. They double their weight during this time and Mom needs plenty of high-fat, high-calorie, high-protein food to keep up with them. This may be the first time you see any physical changes in your pregnant hamster. Pregnant hamsters need plenty of high-quality food and lots of nesting material to get ready for their babies. You shouldn't handle your hamster or her stuff any later than day 14 of pregnancy, to avoid stressing her and endangering her babies. Experienced hamster keepers recommend cleaning her cage and shaking droppings from her nest, then replacing it and stocking up on food and clean water at this time, then leaving Mom alone until at least 10 days after her babies are born.
It's possible for hamsters to have up to 18 young, but it's much more likely yours will have between four and eight. The babies will be completely bald, blind and helpless at birth. Mom needs peace and quiet to care for them safely—it's best to keep your distance for the first two weeks. At around 2 weeks old the babies will have fur and open eyes and they'll be crawling all over the place. By four weeks they'll be weaned and old enough to make even more babies, so they should be re-homed by this time.
You've probably heard that nasty rumor about hamsters eating their babies. It's rare, but it can happen. Hamster moms who sense danger drag their babies or stuff them into their cheek pouches to move them to safety. Sometimes humans misinterpret this and step in to "save" the baby. Other times this evolutionary behavior goes haywire and the mom freaks out and does eat the baby. The best way to avoid this is to avoid stress for your hamster. Keep all other hamsters out of the area and make sure Mom has plenty of nesting material, clean water, food and privacy.
- hamster image by Vasiliy Koval from Fotolia.com