Posted: December 13, 2008, 5 a.m. EDT
Q: We have had two male gerbils from the same litter since January. In the past few months, they have started having disagreements. These began in September and have gotten more frequent. One of the gerbils is dominating the other one. There is a lot of squeaking and then violent chasing around the cage. We have separated them and tried reintroducing them, but the separation times are getting longer. Each time we try to reintroduce them, the chasing begins immediately. When I tried to split them, the dominant one locked on my finger and hurt me.
They are housed in a gerbilarium with three shelves suitable for two gerbils. They still sleep together and groom each other. We let them out to run over us and they have a playpen. The first time it happened, we thought they were fighting over dominance of a treat so we made sure to split the treat in two. We put in two separate food bowls for them. They have not injured each other, no blood has been drawn.
I’m afraid their fights will turn lethal if I leave them together. At one point, I noticed the one that gets chased trying to mate with the dominant one, which I thought might start a fight, but so far they had been getting on well that day. Do you have any suggestions? Do we need to keep doing what we have been, separating and reintroducing? Do they need a bigger tank? We usually don’t take them out at night if they are sleeping. Should we make sure they get out every night?
A: You bring up several good questions. First, here are a few facts about gerbils that may be helpful. Gerbils are social animals, so keeping two littermates together, as you are doing, is a good idea. Gerbils recognize one another only by scent. Sometimes, if they are playing outside their housing, they will get an unfamiliar scent on them. And if you separate two gerbils, they start to lose scent memory of each other. Also, some gerbils can get territorial if their housing (whatever size) has many levels or hiding spots.
This is what I would recommend that you do for your two boys.
- Move your gerbils into a single level house: a 10-gallon, 15-gallon, or 20-gallon tank, with a wire mesh cover.
- Give them plenty to do — use twisty ties to hang a wheel from the tank top, provide deep litter to dig and tunnel in, and give them a small cardboard box or paper towel tube to gnaw up every day. And make sure your gerbils have plenty of food and water. You may want to put the daily handful of food directly in the center of the tank so they can forage for it and build a food store. Plus, no bowl means one less thing to fight over!
- Give them only one wooden nest box in one corner of the tank, so they sleep together inside it and don't set up separate territories.
- After they play outside the tank, put the less dominant gerbil back into the housing first. Give him about 10 minutes to get the familiar bedding smell on him. Then put the other gerbil back in.
- If you need to separate them again, put the more dominant one in a wire mesh cage inside the larger tank. This lets the gerbils keep scent memory of each other and stay safe. Don't worry about dominance mounting — this is a way gerbils show which is stronger without anyone getting hurt.
- Permanent separation is only necessary if they draw blood, and never put your bare hand into a gerbil fight! It is an automatic reaction for fighting gerbils to chomp whatever touches them. Keep a glove near the tank or use an object to push them apart.
I think your boys will be fine. Males hit adolescence at 6 to 10 months. Once they work through which one is the leader and which one is the follower, they will be the best of friends again.