Behavior Enrichment For Rodents

Enrichment is a big buzzword in the field of animal behavior. According to the Encarta Dictionary,” enrichment” is defined as “to enhance or improve the quality of something usually by adding something else to it.” Whether this term is applied to the behavior of a dog, cat, bird, fish, or other animal, the notion is the same: enrichment is the provision of items or activities that improve the quality of that animal’s life.

When people hear the word “rodent,” they generally think of pesky vermin scurrying around. But actually, many rodents are common pets such as guinea pigs, chinchillas, hamsters, gerbils, mice, domesticated rats, and degus (in the rat family). All of these animals can make great pets when they are cared for properly with the right diet and proper housing.

Unfortunately, many people get these animals as pets and don’t realize that in addition to good food, a safe cage, and clean bedding, these pets – just like cats and dogs – need environmental stimulation to be happy and to thrive. Many wild rodents are very social animals living with numerous others of their own kind in their normal habitat. In the wild, they have “jobs” – searching for food, finding mates, and building nests. Most rodents nest in communities and share parental responsibilities. They spend 30-50% of the time they are awake grooming each other. When young rodents are separated from their mothers, they often show an increase in disease, are more anxious and aggressive, and are less likely to play.

Captive rodents that are kept caged and not given anything to play with or to chew on commonly develop behavior problems including barbering (chewing hair off themselves), repetitive behaviors (such as cage bar chewing, jumping, digging, and running in patterns), fighting, cannibalism (of their mates and babies), and repetitive teeth chattering. Studies have shown that rodents provided with different forms of environmental enrichment do not develop these undesirable behaviors.

If you have a pet rodent, there are many ways to provide enrichment. Here are just a few:

Social interaction

In general, many pet rodents, depending on their species, do better in groups. There are species differences, though. Mice normally live in groups with 1 dominant male and several females and young. Mature males housed together may fight. Rats generally do better living in same-sex groups. Guinea pigs may be housed together but mature males also may fight. Gerbils live in large mixed-sex colonies in the wild, so they generally can be housed this way in captivity but must be monitored for overcrowding and fighting. Finally, hamsters are usually not social and can be housed individually.

If you are planning to introduce a new rodent into another one’s territory, there are a few important things to keep in mind.  First, scent or smell is a very important sense in these animals; new individuals should be introduced only into partially cleaned cages so that they can smell the original animal before actually meeting him. Second, the cage must be large enough to house more than one animal. Twice the number of animals means twice the needed space. Overcrowding can lead to fighting, injury, and even death.  Third, all introductions should be done gradually and monitored carefully. Don’t just put the new pet in and leave, expecting cage-mates to work it out. Both the new and the original animals may be stressed initially – sometimes hiding and not eating for a day or two. These animals must be watched closely to ensure that neither becomes ill and that eventually they both settle in. If not, they may not be compatible. Finally, realize that if you house opposite sexes together, you will definitively end up with babies unless you neuter one of the pair. A rodent-savvy veterinarian can give you advice about the best strategy to deal with this if you are faced with this situation.

Light exposure

Many rodents are nocturnal or crepuscular (most active during dawn and dusk). For these animals, in particular, the presence of flickering fluorescent-type lights or long periods of daylight may induce stress. Short-term exposure (10-20 minutes, 1-2 times/day) to low-level natural sunlight is best for most rodents. This can be accomplished in warm weather by placing the cage next to an open window or moving the cage with a wire mesh top outside so that direct sunlight can come through it. Remember, if you do take your rodent’s cage outside or put it in a window, be sure to protect your pets from predators, don't allow them to overheat, and provide them with hiding spots. Rodents benefit from short periods of direct sunlight not only because of the behavioral effects but also because of the health effects. Direct sunlight exposure may decrease bone density problems by promoting vitamin D production in the skin. So, short periods of sunlight can be beneficial both behaviorally and physically.

Substrate enrichment

Substrate is the material that you provide at the bottom of the cage. Different species have different preferences for substrate. Mice, gerbils, and hamsters like deep bedding for nest building and to maintain their high body temperatures. For these animals, bedding colored close to their fur color should be provided so that they feel safer blending into their environment. Types of bedding that work well for these pets are shredded paper or newspaper, tissue, and commercially available soft paper bedding such as Carefresh.®  Guinea pigs may be housed on flat surfaces covered with paper bedding and hay. Chinchillas need to be kept at cooler temperatures since their thick coats make them overheat easily. They may be housed on flat surfaces covered with paper bedding and hay. They also need to roll around in fine sandy dust (available in most pet stores) to remove oil and to decrease moisture on their skin. This dust mimics the material they bathe in the wild to clean their fur. If it is very humid, they may actually require a dehumidifier to maintain their skin and coats.

Regardless of the species, to increase the enrichment experience, you can provide more than one type of substrate in different areas of the cage at different times of the day. Substrate should be changed regularly to decrease ammonia build up from urine, but since familiar scent is so important in decreasing stress in rodents’ lives, only partial bedding changes should be performed so they don't have abrupt changes in smell.

Toy enrichment

All rodent species live more happily and have fewer behavioral problems when provided with toys. All species like to run on wheels. Wheels should be smooth-sided inside to ensure safe footing (without holes to get feet caught and without a rough surface that can be abrasive to feet). If there is more than one rodent in a cage, there must be an adequate number of wheels for everyone, or cage-mates may fight for access. In addition to wheels, hiding areas are essential for rodents.  They are especially important in making animals feel safe. Cardboard boxes and tubes (from paper towels and toilet paper) and plastic hide-outs (Tupperware containers with a door cut out) work well. Hiding spots are environmentally enriching to rodents, but their use may need to be limited if they subdivide the cage and promote territoriality and aggression.

Foraging enrichment

Providing small objects to interact with is essential for all rodents.  For smaller species (mice, rats, gerbils, hamsters), great things to try are pine cones (which must be free of parasites and sap from untreated trees) and deep bedding for tunneling. For guinea pigs and chinchillas, items to try are grass cubes and straw to gnaw on (hay woven into small huts, tunnels, mats, and twists commercially available from Oxbow® Animal Health work great) and cardboard hide-outs. Ensure there are an adequate number of hide-outs to prevent fighting for access. For all rodent species, small wood branches from untreated trees free of sap and parasites can be terrific foraging toys. Other great foraging toys for rodents are commercially available, as well, from sites such as www.BusyBunny.com and www.bio-serv.com.

The best thing about many rodent toys is whether you make your own enrichment toys or purchase them, they can serve as a food source, a hideout, and a play object all at once. Now, what other species can be so versatile? Rodents really are neat little pets.