Sexing
What is sexing? Simple: telling males and females apart! This is done with the intention to separate them, because hamsters are rodents and they breed fast. A pair can become a colony in a matter of months thanks to their short gestation periods, so unless you have the resources to rear them all, or have arranged new homes for them, breeding should be avoided.
But how do you tell males and females apart? I've read guides detailing how you should flip them over and look for tiny holes where their anuses should be, and I didn't personally find them helpful. First of all, they have hairy bottoms, and if your winter white is particularly furry, it would be a bit difficult to look for the so-called 'holes'. Adult males and females are easier to tell apart (you don't even have to pick them up), since adult males have visibly larger testicles than baby males. These are the two large lumps growing near their tails, and females obviously don't have them.
But like every other animal, hamsters reach sexual maturity and are able to breed at an early age - when they're 'teenagers'. In younger hamsters their testicles aren't so obvious, so here's where it starts to get confusing. Again, as they're younger, they're also a lot livelier, so prepare for lots of squirming. This is going to sound gross, but it helps if you feel around for their balls. Because of all the fur, I find it much easier to push away their fur, and then confirming that there are actually balls beneath them. Because of this furry reason, putting them in a transparent box and then peering from below is very risky and inaccurate method of sexing. If, like me, you've had them since birth, it's easy to make an estimation on how many males and females there are in a litter before their fur starts to grow. Why? Because the baby male's penis is easier to spot when it isn't obscured by folds of skin and fur. The reason why you can only see testicles in adults is because the male's penis is withdrawn. Not kidding.
After that, I simply use the elimination method to sex them. After confirming all the males are indeed males, then everyone else has to be female. I find it easier to do it this way since some females can be real butches with their 'holes' being further apart than usual.
Moral of story: Look for the balls! Holes are Plan B.
Sexual Maturity
Like puberty in humans, it hits at different ages, depending on the individual. Some hamsters, particularly pearl winter white males, have a higher rate of infertility, though that doesn't seem to be the case anymore (I've bred them successfully).
Females become fertile when they are around 4-5 weeks old, and males sometimes as early as 3 weeks. It is, however, not advisable to breed a young female - wait till she reaches around 4 months old; she'll be strong enough to nurture and care for her offspring.
Males mostly remain fertile throughout their lives, but females become sterile after 12 months old.
Mating
Now that you can successfully tell males and females apart, and when they hit maturity, mating ought to easy. If, unfortunately, your pet shop has incorrectly sexed your two hamsters, and you have a female-female or male-male combination, then obviously there aren't going to be any babies.
Female winter whites come into heat approximately once every 4 days, and notice I said approximately. Plus minus a day - sometimes it can get irregular. How can you tell if they're in heat? Some sites claim that females freeze/raise their tail when gently stroked down their backs with a finger, though this behaviour has never been displayed in my winter white before. She either started to turn and smell my finger, or arched her tail down due to the pressure of stroking, despite me being gentle. And these two happened on the day she was in heat, because she reacted differently to an actual male (as opposed to my finger. I don't think they're that stupid.)
The only way I think you can accurately tell if she is in heat is to place her in the male's cage, or on neutral ground. Never place the male into the female's cage - she might be territorial and turn aggressive towards him. If she is indeed in heat, she should be less aggressive/territorial compared to normal, and might stiffen and raise her tail to signal her willingness to mate. If the female is less aggressive than the male, then she should not squeal or run away from him. Again, all these may not happen immediately, so keep them together for about 30 minutes, unless vicious fighting occurs. Keep watch!
If the female accepts the male and isn't attacking or running away from him, then keep them together for a longer period. He will eventually sense her presence in the cage, seek her out, chase her, and then attempt to mount her. Between the actual mating, you'll find him trying to flip and sniff her (usually her ears). This is normal - he's just making sure she is really in heat, because the glands that tell him so are near her ears.
From my own experience, one mating session isn't enough. After about 5 unsuccessful sessions, I was starting to think that either one was infertile. I then came across a site (a site with an e-book preview, actually. Unfortunately I can't find the link, sorry) that mentioned a hamster's ability to prevent pregnancy when the male is kept away from her. Amazing? You tell me.
Basically, it had something to do with her being able to curb the development of the foetuses after sensing the male's absence through his scent and hormones (pheromones?). Why this? Because in the wild, the male stays to help defend and raise the pups! Once the female senses he's not there, it means he wouldn't be helping out. Remember, this is in the wild. It's a different story in captivity.
So if your female doesn't seem to be pregnant after a few mating sessions (by sessions I mean removing the male after he mates with the female every 4th day when she is in heat), then leave the female together with him. This is the tricky part. Will she fight and refuse to mate after every 4th day? It depends. Mine didn't. Anyway, after this method of prolonged exposure and mating with the male, she finally got pregnant.
Pregnancy
Well, I have very little to say about pregnancy. It is near impossible to tell if a female is pregnant, and I didn't know mine was until she pooped babies out! Unless a hamster is heavily pregnant and is about to produce a large litter, it is very hard to tell if she is pregnant at all, because unlike humans, her belly may be stuffed with five pups, but it doesn't create any noticeable bulge. Even if she were carrying a large litter, the bulge would only be noticeable about two days before birth. Winter whites have a gestation period of 18-21 days, though like I said before, they have the ability to delay their pregnancy if they are nursing a current litter, or if birthing conditions are not right. Some have also been known to reabsorb or miscarry if conditions are unfavourable for raising the litter. The average litter size is around 3-9 pups, although there can be as little as one, to as many as 14.
I have gathered a few pointers on the web to tell when a hamster is pregnant, but you should know that my own female displayed none of them. If she did, it was normal everyday behaviour (like hoarding food, building nests to sleep in, etc.). These signs include:
- drinking more water
- building/relocating nests
- raised nipples
- being more aggressive than usual
If you think your hamster is pregnant, give her more nesting material to build her nest, and remember to replenish her food and water supply. Remove any potentially dangerous objects like the wheel and any tubes. Try not to handle her too often, and also remove confined spaces. This is for your own convenience, for those who want a peek into the nest. You should check once in a while what happens after birth in the nest, since there are cases where pups die and need to be removed. Most of the time the mum will eat the dead (don't worry, they do this in the wild to prevent decomposition, which attracts predators and scavengers). If she doesn't do it, then you've got to step in, but make sure it's really dead (!). If you're sure it is, this is the only exception when to disturb the nest. Try to do it as quietly and as undisruptive as possible - use a spoon instead of your hand to move any babies if necessary. Remember to rub the spoon into the bedding to mask its foreign smell, and scoop up pups together with any surrounding bedding.
Also note that any bedding should not be changed for three weeks from the date of birth. If it is necessary to clear damp bedding, use the spoon method above. Therefore if you're sure your hamster is pregnant, roughly estimate the date she'll give birth, and clean out the cage before the babies arrive.
Birth
Rule of the thumb: DO NOT make any sudden noises or disturb the cage when the female is giving birth. Also: Remove the male before birth (winter white males play a part in raising the litter, but this is not crucial and best avoided if you don't intend to start a colony... more later).
Hamster births are clean affairs, and any blood shed are in such tiny amounts they're hardly noticeable. The female will give birth around the cage, so don't be alarmed if the pups are scattered about and not in one place or in the nest. The process can take as long as an hour, with about ten-minute intervals between each pup. Pups are not born consecutively, and the female will be active, walking about, eating, even exercising on the wheel between the birth of each pup. (This is discouraged, as any injury or fall from the wheel may complicate birth. Remove the wheel towards the end of the pregnancy if possible.)
The female will usually give birth at night, when they're more active. Also, pups may appear lifeless and unmoving, but that's normal (unless of course, they're stillborns). DO NOT TOUCH THEM. Resist from prodding or poking them, because the female may reject the pups, or cannibalise them as a defense. Touching them changes their scent, and the mum may be unable to recognise it as one of her own. New-borns are pink and born without fur; they are also deaf and blind. They may remain extremely still for some time, then start wriggling, then remain still again.
When all the pups are born, the female may wash herself, gather her pups, clean them, and then start suckling them. Some of the pups may wriggle out of the nest, but don't worry - the female will gather them together again. There can be more than a single nest, so pups may be scattered in groups in different nests. Do not move the babies if they wander! While suckling, you can see the pup's stomach through their thin layer of skin - look for a white patch on their bodies - this is a full stomach of milk!
Remember I mentioned to remove the male before the female starts giving birth? There are actually several reasons why. Firstly, we can't predict how the mum would react to the dad in such an enclosed space (how big can an indoor cage be, compared to acres of land in the wild?). She could get aggressive, attack the dad, and kill the pups in defence. Or, the dad could kill the pups. Or, the dad could kill the mum, leaving the pups without their precious supply of warmth and milk. You can never be too careful.
Secondly, the mum does fine raising her kids alone without the dad's help. A much better alternative than to leave the dad in.
Thirdly, the mum goes into heat immediately after giving birth (I can never understand why evolution is this crazy), and the dad would most likely mate with her again. Yes, the female just had a litter, but besides having the power to prevent pregnancy, she is also just as capable delaying it. She could raise the first litter, then give birth again, but either way I'm sure you wouldn't want to end up with a colony in such a short time. Not to mention the kind of stress on the mum's health to be nursing two consecutive litters. Babies grow up weaker, have birth defects, et cetera, so... no. Remove the dad. It's the lesser of two evils.
Rearing the Pups
Hamsters are independent creatures, in case you're still unconvinced. They clean up after themselves no problem, and don't go into labour like humans. You won't have to do much to rear the pups - in fact just the opposite. Disturb the nest as little as possible, except to refill water and food. Needless to say provide the nursing female with extra food, particularly foods high in calcium and Vitamin D. The mum will do the rest, and at this point what the pups need is warmth, and milk. The female may take turns feeding the pups if it is a large litter, and she may once a while wander off for 'alone time', leaving the nest to clean and feed herself. This is normal - she is not abandoning the litter! They can survive without her warmth for a while. The female will later return to the nest after her break, and suckle them again.
Help! My hamster is eating her young!
Cannibalism, though a horrible concept, is part of a female hamster's defence for her offspring. "If I kill and eat them first, you can't eat them." It doesn't make sense, but that's nature for you sometimes. If you're lucky, she's just temporarily stuffing them into her cheek pouches to protect them, but why even give her any reason to? She'll do that when frightened, startled, or alarmed, so once again: don't touch the babies, and don't disturb the nest! I can't emphasise this enough.
Sometimes though, cannibalism happens, whether its your fault or not. Chances of this happening increases when:
- There is not enough protein in her diet.
- The litter is too large for her to care for every one of them.
- The pup is weak or deformed - she is "pruning" the batch.
- She feels defensive because of an intrusion or a disturbance.
- She is an inexperienced mother, or a first-timer, or a young mother.
If this happens - and I have never experienced it so this is my logical opinion speaking, not experience - remove the dead body, if the female hasn't already finished it first. Do not remove the mum or agitate her further, and do not separate her from the remaining pups - they need her milk and warmth. There's nothing much you can do, really, if she goes on and cannibalises the entire litter. Unless you're willing to and experienced enough to care for them without their mother (providing a source of warmth and dropper-feeding them milk every two hours, even through the night), then chances are they're not going to survive even if you remove the mother.
The pups' chances of survival increases each passing day, and most of them do survive if the mum knows what to do - so here's a summary of their development for the next three weeks. Note that some babies may turn out to be runts and develop at a much slower rate than usual - this is because they aren't getting adequate amounts of milk (large litter size, problem with the female's teat, etc.). I've never dealt with this, so I'd rather not comment.
Litter size: 3-9 (1-14)
Gestation period: 18-21 days
3 days
- skin darkens
6-8 days
- fur appears
- start to regulate their own body temperature after 7 days
10 days
- ear-flaps start to open
10-14 days (2 weeks)
- eyes open
- start to explore nest
- start to take solid food
- can handle
16 days
- clean cage
3-4 weeks
- fully weaned and totally independent
- sex them and separate
4-6 weeks
- sexually mature
4-7 weeks
- separate from parent
16 weeks
- optimum breeding age for females
Here's a list of what to feed the female for extra protein and calcium:
- carrots
- dog food
- cheese
- veggies
- egg white
- hard boiled egg
- nuts
- sunflower seeds
- fresh cooked meat
- tofu
Apparently bath sand is toxic to newborn pups, so remove any from the cage. Better be safe than sorry - I have never tested it, but it's something to note.