You are here:

Mice/Two mice chewed off their tails last night


QUESTION: I have never seen this before and I am quite dumbfounded. I was doing my routine checkup that I do every morning since two of my five mice are sickly. I noticed that two of my mice (one sickly mouse, and one healthy) had eaten off the ends of their tails and were sleeping in the food dish, somewhere they never sleep. I'm positive I feed them enough, but could this be the reason still? I gave them more food right away, but I have no idea what to do about their tails. I'm a rather squeamish person so this is not my forte. A vet can't exactly be in the question either, since an appointment was already planned to bring in one of my rats today and I'm on a budget. Is there anything at all I can do for their tails at home? It looks awful and I can imagine they're in pain. As an endnote, these two mice are sisters. I don't know if it has anything to do with this, but I've heard of mice having a psychological self-harm behavior.
Thanks for your help.

ANSWER: Hi Drea,

I haven't had a chance to think too long on this, but I wanted to respond very quickly in case there was any chance you hadn't been to your vet appointment yet.  Can you call your veterinarian and ask if you can save money by bringing the mice in for the same appointment as the rat?  I ask because the bulk of many vet appointments is the office call fee - if you are already going to be in there, they may only charge you an exam or medication fee for the mice and you can cut your bill in half of what it would be if they had their own appointment.  It's worth calling and asking them, just in case!  If not, you can always ask them questions about your mice or pick up antibiotics in the same visit without bringing them in.

There's a chance they didn't do it to themselves but rather to each other.  Do they or the other mice ever fight?  Some chasing can be normal, but squeaking, boxing (punching out), tail rattling (buzzing it against something hard), or biting hard enough to hang on or cause scabbing are all signs of serious fighting that needs to be stopped.  I feel like you would have noticed this earlier, but since they woke up sleeping separate from the rest of the mice, it's a possibility.

Were their tails totally normal before this, or is there a chance it's been going on for a little while?  If they had injuries to their tails, they could have chewed them away as a result of excessive pain or necrotizing tissue.  Sometimes a severe bite to the tail or an injury will result in the tail shriveling up and falling off on its own, but you probably would have seen it several days ago if that were the case.  I don't think this is the most likely possibility, since it happened simultaneously, but it is still one of the options.

While a mouse can develop a neurotic tendency toward self harm, the chance that both would develop it at the same time, even with them learning from each other, seems unlikely.

The last option that comes to mind is an injury.  This sounds gross, but can you find the tails?  They might point you to an area in the cage where it happened.  If they have a wire or open style wheel, it's possible their tails could both have been damaged while playing.  Is there anything else in the cage that they could have been pinched in?

As far as taking care of the injuries, you are going to need a twofold approach.  First, it is crucial that you keep the tail tips clean.  You will need betadine, gauze, ointment, and dixie cups.  Drip a few drops of betadine (a safe iodine mixture you can find in the pharmacy) into a cup of warm water until it turns the color of dark tea.  Then dunk the tail tip a couple of times into the solution (not the whole mouse!!).  Let it sit on the tail for a few seconds, then rinse away with a cup of warm clean water.  Dry completely with woven gauze.  Apply a very thin layer of triple antibiotic ointment over any broken skin 2-3 times a day.  They'll groom most of it away, but what is left will help to keep gross debris out of the wound.  You can clean the tail 1-2 times a day.

The second thing you'll need to do is get them on antibiotics.  The whole colony can be on them, but since we don't know if this was aggression or injury, you might need to separate them for treatment anyways.  A tail injury is major - there is a main vessel that runs down the length of the tail, and this puts them at a high risk for infection.  The best option is an antibiotic from your vet, but if you cannot get one, please let me know and I'll try to help you find something else like tetracycline.

If I think of anything else I'll revise this answer, but otherwise, please write me back with updates and I will do everything I can to help.  Best of luck to the little girls!


---------- FOLLOW-UP ----------

QUESTION: I cannot find the tails, and I think they've been eaten. I haven't noticed any serious fighting before now and their tails were perfectly fine. I've never seen any scabs or injuries other than this.
Unfortunately, I took my rat to the vet right after posting this question, so I have already been there. As for tetracycline, I have heard of treatments with it, but have not done it. How exactly would I go about using it?


Oh, darn.  I'd hoped I'd get to it fast enough - I'm sorry about that!  In any case, tetracycline can usually be found at pet shops in the fish section.  The instructions on how to use it are listed out by our other expert Natasha over here:

But just in case that link doesn't work, here's what it says about dosages and administering it:

"You are going to put some in her water bottle and try to get an initial dose inside her.  

If you have the capsules, empty one capsule into a large water bottle or one half into a small one.  Shake extremely well.  If you have the powder,  1/4 flat teaspoon measure is the same as 1 capsule.  If you have the tablets, completely crush them into fine powder with the back of a spoon and use as powder.   This should be her only water source.  It's fine for any other mice to drink the water too, unless they are pregnant or nursing, so it is good that you have two separate cages. Cover the water bottle with tin foil,  because the medication is sensitive to light.  They may chew on the tin foil, because some mice love it. Don't worry about that. It's great for their teeth!  Clean the bottle and change the water every few days for 10-14 days.

Next, take another capsule worth and mix it with one drop of water.  This will make a paste about the consistency of mustard.    You have plenty to play with, so if the mixture is too watery, try again.  Now pick up the mouse by the scruff of the neck.  This is the skin just behind her head.  This does not hurt her-- it's how her mama used to carry her-- but she will struggle valiantly.   Holding her gently but firmly,  quickly place a small amount, maybe 1/4 pea size, into her now open mouth.  This is hard.  Be careful of her nose!  Wipe a bit more onto her whiskers and chin.  She will ingest that when she washes herself.  If you couldn't get any inside her at all, wipe some more on her head and sides.  Put her back into her cage so she will wash herself.  Keep any other mouse from washing her, if necessary removing the other mouse for an hour."

If you don't think it was due to fighting, you can treat them all together.  Tetracycline will not harm the other mice.  Please keep me updated, and if you can't find tetracycline, write me back and I'll see what else might be available without a vet.



All Answers

Answers by Expert:

Ask Experts




I can answer questions regarding mice as pets, mouse behavior, color and coat genetics, breeding techniques, and general health questions. I can help with caging and setup, nutrition, social issues, and what to do in most mouse emergencies (such as unplanned litters, injuries, fighting, etc.). I can also assist with questions pertaining to orphaned mouse pups, weaning litters, and questions of mating and birthing. I cannot answer questions about exotic or wild varieties of mice such as spiny or pygmy mice. *****FOR EMERGENCIES, anything requiring immediate medical intervention, PLEASE take your mouse to a professional veterinarian or wildlife rehabilitator who works with mice as soon as possible! IMPORTANT RESOURCES: Raising Orphaned Mice: Orphaned Mice Videos: Natasha's Your First Mouse: General Mouse Help: Mouse Info and Exotic Breeds:


I have enjoyed the companionship of mice nonstop since 2004, and spent a year caring for them in a lab where I learned a great deal about their breeding, social needs, and health. I spent a few years breeding them, specifically working with albinos, marked mice, angora mice, and satins. My education never stopped - I am learning something new every day from current and well-established research thanks to the wonderful folks at the Jackson Laboratory, as well as from my wonderful mousey friends online. I also love learning from my terrific questioners here on AllExperts - you folks keep my passion for these amazing animals alive and well!

East Coast Mouse Association - expired, American Fancy Rat and Mouse Association - expired

Partial University for a B.S. in Microbiology, Partial University for a 2-year degree in Veterinary Technology (RVT cert), C.E. classes in pathogens, aseptic technique, genetics, and applications

©2016 All rights reserved.