Hedgehogs are seldom overtly aggressive, but the maxim "anything with teeth may bite" certainly applies. In order to know how to manage that behavior, it's important to look at why the hedgehog is biting. The most common reason is because there is something on your hands that smells yummy, and they want a taste. In this case, they will often lick first, and the bite is more of a nip. Keep in mind, hedgies can find some strange things yummy, like tobacco smells or soap smells, so this may be occurring even if you have just washed your hands or haven't recently had anything you'd consider yummy. Probably the best way to manage this kind of biting is what behaviorists call response prevention. Watch carefully, and if hedgie licks or shows any other sign of biting, move your flesh so hedgie simply can not bite.
In young hedgehogs, biting/nipping may be a way of exploring the environment. This may or may not be preceded by a lick. To discourage this behavior in babies we think have gone overboard with the exploratory nibbling, we use a mildly aversive "air puff" technique. We watch the hedgie carefully, and as soon as it begins to open its mouth we blow a puff of air toward the hedgie. The hedgie's natural response is to lower the visor or ball up. It can't bite when it's doing that, and it usually only takes about 2 to 4 times of doing this for hedgie to learn that trying to bite something that smells like human flesh leads to something uncomfortable, and to stop.
In hedgies who don't normally bite, biting is probably a way for the hedgie to communicate something. Your challenge is to figure out why. Some hedgies do not like to be handled for very long, or may become uncomfortable in a noisy environment, and the bite is their way of saying, "This is too much. Put me down." Usually the hedgie will squirm and otherwise let you know it's not happy with the situation before it bites, so learning to be attentive to what hedgie does before the bite can help you to keep hedgie happy so he or she doesn't have to bite to express displeasure.
There are a small number of hedgies who just seem to bite very consistently and for no apparent reason. It is also very important to rule out health concerns as a possible reason, as some hedgies may bite because they don't feel well and don't want to be messed with. Out of the several hundred hedgies who have passed through our home in the last 5 years, I think there have only been two that really fit this category of determined biters with no health problems and consistent biting behavior. One of them appeared to have been hormonally driven. He was a male who came from a line of very friendly hedgies, but he would constantly bite, even going so far as to bite through cloth. Once bred, he completely stopped this behavior and in almost 2 years has never fallen back into his biting pattern. The other was a life-long, incorrigible biter. We found that with her, if we didn't put flesh in front of her, she didn't bite. So, I learned quickly to pick her up in a way that kept her happy and my fingers out of danger.
Although I have not had to use aversive techniques to manage biting in hedgehogs who fall in that category of incorrigible biters, I have heard of others who have had success. The technique that was described to me involved keeping a q-tip dipped in rubbing alcohol (a very unpleasant smell) handy. When the hedgie bit, the person would touch the q-tip just above the nose. This gave the hedgie a very nasty smell to associate with the biting, while not endangering sensitive nasal tissues by actual touching of the alcohol to the nose. The report I got is that this person's hedgie stopped biting after just 2 or 3 trials. As a trained behaviorist, I would recommend trying to apply the aversive (alcohol smell) before the bite happened, as I would rather teach the hedgie not to bite without actually having to be bitten. I would also caution that if the biting continued after 4 or 5 trials, the technique should be considered a failure and discontinued. I would also attempt the puff of air technique before trying this technique, since it is always best to use the least level of aversiveness possible. If hedgie's biting continues after all of these techniques have been tried, you may want to ask your veterinarian if he or she has any ideas, or if there is an animal behaviorist in the area that might be willing to consult.
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