Solitary or gregarious?
Al l animals can be put into one of two categories, depending on their behavior towards others of their kind. Some animals live in groups, just as humans. We call these gregarious animals. These groups can have very simple structures, where the animals live next to each other, but more of less live their own lives. We see this with mice, for example. There are also animals which live in groups with very clear, strict rules. The prairie marmots, for example, have real group leaders, which are respected and obeyed by the other group members. Very often, each animal has a certain task to fulfill within the group. Most rodents are gregarious animals.
Some rodents are solitary, which means that they prefer to live on their own. They only meet up for mating in the reproduction season. The male has to make sure that it gets away quickly after the mating, as the female can injure it badly. A solitary lifestyle is often led by animals which live in dry grassland and desert areas, such as some desert mice and some special gerbils. Solitary animals often have a very strong territorial instinct. This is also obvious with some squirrels. It is very obvious that gregarious animals are very forgiving. When observing a group of mice, you can see that they have reconciliation signals: turning the head away and/or closing the eyes. The willingness to compromise aims to prevent injuries and deaths in the group.
When an animal is willing to succumb, it is not likely to be attacked. This assumes that the animals have got enough room to escape from each other. When gregarious animals are forced to live together in a very small cage without escape options, it can cause fights. This can also happen when two gerbils that are not familiar with each other are put in one cage.
If you can to keep rodents, it is therefore very important for you to know whether your chosen animals are gregarious or solitary. A solitary rodent, which is forced to live with others, will feel constantly threatened by this situation. The animal will be unhappy and become aggressive. On the other hand, it is wrong to keep a gregarious animal on its own. It will be very unhappy and will finally pine away. It should be obvious that you should never keep a gerbil on its own. It does not only need a partner to play with, but also to scratch each other. Gerbils are just like humans in this respect: they need protection and affection.
Gregarious animals often live in colonies, which may consist of just three to eight animals, or of several thousand. Mice and rat colonies are usually very big; gerbil colonies are a little smaller. A group of Mongolian gerbils usually consist of three grown male, two to seven grown females and several young and adolescent animals. The colony behavior is vitally important for the existence of the group. The members of the group build a system of burrows with nesting and storage rooms. While the group rests or looks after the young, a few members watch out or dig around a little. As soon as danger approaches, they begin to drum the ground with their back paws to warn other animals. Another function of group behavior is to ensure a good rest. When colony animals sleep, they pile up in a heap. The youngest animals are on top. As little warmth as possible can escape, and the strongest animals protect the weak young. In cold times, the small animals with very little body volume cannot keep themselves warm. If they were not covered by others, they would die of hypothermia. Colonies have no set pattern. Animals with a free order, such as mice and rats, constantly change their composition. With smaller (and therefore closer) colonies, this takes much longer. An alpha male of a gerbil colony therefore keeps his position for two years. He is then too old, and a younger male will take over the lead. Adolescent males cannot normally measure their strength against the adult males. They are therefore often thrown out of the group and swarm around in small bachelors’ groups, until they can found their own colony. If no young females are found, the young males stay together.