Introducing Rats to Other Rats

Rats of all ages and backgrounds can be introduced to others (of the same sex!), and can happily live in large groups.

It is essential to introduce unfamiliar rats on neutral territory, which doesn't smell of either one e.g., a room which the rats don’t normally play in.

A bed or settee can be good places to introduce rats, or the bath but perhaps put an old towel in the bottom as rats don’t seem to appreciate the slippery surface.
It’s not always wise to use a cage, as if things go wrong it may be difficult for you to intervene.

NB. Behaviour displayed towards other rats through the bars of a cage is not always a reliable indication of how they will interact outwith their cages.

Stay calm - rats are very sensitive to human emotion, if you are anxious, they will pick up on it and react accordingly.

Things that can help keep everyone calm (including you!)–

•Chamomile tea

•Cucumber

•Bach’s Rescue Remedy

When they meet –

Some tussling is needed to establish the pecking order (social hierarchy). The general rule of thumb is ‘no blood, no foul’, but check your rats over carefully after any altercations, as bad bites can lacerate the skin but cause little or no bleeding.

Things to watch for –

•Puffed fur – a sign that the rat is stressed/anxious/going to become aggressive.

•Writhing tail - a sign that the rat is stressed/anxious/going to become aggressive.

•Hissing – often territorial aggression but can also be nerves/anxiety

1. •Scent marking - one or both rats rubbing themselves on every available surface.
   

2. •
   

Once in close proximity rats may –

•Sidle up to one another and push against the other.

•Kick one another with their back legs

•Stand up and box at one another

•Stand up and stare at one another

•Freeze

•Try to get under the other rat to sniff their 'privates'

•Chase/flee

•Young and submissive rats may roll over and present their bellies

•Mounting - to exert their dominance.

These behaviours can go either way depending on how the other rat reacts. Some rats will take turn about displaying these behaviours, some will run away and others will try to dominate proceedings.

When things get lively –

Rats may bite at one another. Generally bites to the rump and underside can be seen as aggressive, whereas bites to the back of the neck tend to be less serious and are often no more than tugging.
However, if the rats do decide to fight, what began as a well aimed bite can land anywhere. If one or both rats are biting the wounds can get pretty serious and introductions need to go back a step and proceed slowly and with great care.

Rats may pin one another..
This involves the dominant rat pushing the underdog onto his back and either holding him there or standing over him preventing him from getting up.
If your underdog lies there without struggling, then they have usually accepted their place in the hierarchy and there ought to be limited tussling from now on. However if they struggle and try to reciprocate then dominance is still being vied for.

When to intervene –

This is often down to personal choice and experience. It’s worth noting that rats can squeak a lot, and it can sound quite distressing especially when babies are being introduced to adults.
Try not to intervene for that alone as it is something that should pass once the rats are more familiar with one another.

Rats NEED to go through a lot of the behaviours listed above before they can be housed together.
However if one rat automatically flies at the other and they end up as a rolling ball of fur, then it’s time to intervene. You may want to use oven gloves or a tea towel when handling them. A plant spray, or water pistol full of water may also be useful. If any fights ensue, squirt the rats. They should stop fighting to wash themselves.

NB. Intact boys can need at least an hour for their hormones to subside. Therefore, if you have to handle a worked up, hormonally aggressive, intact male, do so with care and leave him alone for at least an hour before attempting to interact with him as you normally would.

If any blood is shed, or there are other serious injuries, then it’s also time intervene.

Try to end each meeting before things get to the stage where you need to intervene, and gradually increase the time the rats are together. This can begin with seconds and work up to minutes and finally hours.

Living Together –

Ideally you should let the rats meet on neutral territory, several times before attempting to house them in a cage together. This gives them ample opportunity to agree on the hierarchy between them, and gives you time to ensure they are getting along for extended periods.

When you feel they are ready to try living together there are a few steps which can make the move less stressful for everyone.

If it is obvious that one rat is more dominant than the other (e.g. an adult and a baby), put them in the passive rat’s cage (without cleaning it out). The weaker rat will feel more confident and the dominant rat will be less aggressive.

Some people suggest putting each rat in the other's cage in turn before you introduce them, so that they get used to each other's smell. However, rather than confining each rat to a strange cage, which may make it frightened, try just leaving the empty cage open while the rat wanders around, so it can explore and leave again at leisure. Rats don't have a 'colony odour' that can be transferred onto new rats.

If using the more dominant rat’s cage, then clean it thoroughly to remove all smell of the previous resident. Biological washing powder is supposed to be very good at removing smells, but remember to rinse thoroughly.
Rearranging the shelves and providing new accessories will also help.
These precautions help reduce the chance of the previous occupant displaying territorial aggression, because the cage will no longer be as familiar and scent marked as his.

You need to remain observant of your rats’ behaviour. Watch for territorial behaviours ie. try to control the food bowl, sleeping arrangements etc. Some rats can end up bullying a very submissive cagemate without resorting to fighting.
The other rat may become very quiet and withdrawn; get nervous around you; lose weight; get recurrent bouts of mites; begin barbering themselves.

•Sleeping together

•Eating together

•Sharing the water bottle

•Grooming one another

Problem solving –

Male rats are often cited as the most difficult to introduce to one another. However hormonally aggressive males can often be helped enormously by castration.
This removes the testosterone and the rat becomes much more subdued but does not lose any of their personality.
Neutered males can happily live with entire males, and also with females. Aggression is generally much reduced two weeks after neutering, although some males seem to benefit instantly, and others take a while longer.

Tardak is also an option, but only as a temporary measure. More information on tardak at www.ratz.co.uk/tardak.html.

Female rats are generally very accepting of one another and new girls can move into the colony very quickly.
However sometimes one (or two) rogue girl will be awkward whilst the rest are getting along.

In these situations it is often helpful to remove the aggressive girl and allow the new rat to move in and establish herself in the colony with the others.
Sometimes this takes several hours, sometimes several days.
The aggressive rat can then be put back into the cage and is generally accepts that the new girl is now part of the family.

Mana Rattery 2005

Thanks to  Einstein and Lloyd, Dhillon and Ling, Hannah, Switch, Kimi  and Hazel, Sandy, Ski Whisker and Pi for  the photos.