Temperament Scoring

Up until now I’ve just judged my rats’ temperament by the overall feel of them, but the other day I found a grading system for temperament and decided to write a similar one to use on my own rats and future babies. (Feel free to use/modify it as you like!) A lower score suggests a rat with a less ideal temperament and a higher one suggests a calmer, more laid back rat.

Test 1: Hands
Put your hand in a limp fist in the rat’s cage and observe what it does.

  1. Runs and hides and does not come out, or bites
  2. Ignores you, does not approach
  3. Cautiously sniffs but does not touch your hand, or touches but uses more teeth than you’d like
  4. Touches/sniffs but backs off of you move your hand
  5. Touches/sniffs/licks, does not react in a nervous manner if you move your hand

(Sorry for the rubbish quality, but here are a bunch of 5s)


Test 2: Scruff
Pick the rat up by the scruff, hold for 5 seconds.

  1. Lots of squirming, squeaking and general uncomfortable signs
  2. Less vigorous squirming which may start after a second or 2
  3. Squirms for a second or 2 and then stops and holds still
  4. Holds still
  5. Tucks back feet into tummy, is limp, relaxed, and still

(Azriel, Mouse and Otter: 4.5, 4.5 and 5)

Test 3: Fingers
Poke a finger through the bars of the rat’s cage and observe how the it reacts (skip this if you know you’ll get chomped though!)

  1. Biting (not gentle nibbles, actual biting)
  2. Runs away/does not engage with you
  3. Runs away at first but then comes back to have a look
  4. Sniffs fingers cautiously
  5. Licks fingers/grabs with paws/gentle mouthing

Test 4: Upright hold
Wrap your fingers around the rat’s shoulders and hold it upright with its back feet either dangling or on the palm of your other hand.

  1. Vigorous wriggling and trying to get away without giving up
  2. Wriggling, but not as committed to escaping as a 5
  3. Mild wriggling, or stays still for a few seconds but then tries to get away
  4. May wiggle for a few seconds but then stays still
  5. Stays still and relaxed, does not mind what is happening

Test 5: Lie Back
Hold the rat in two hands and lie them on their backs between your hands with fingers holding them in position.

  1. Vigorous wriggling and trying to get away without giving up
  2. Wriggling, but not as committed to escaping as a 5
  3. Mild wriggling, or stays still for a few seconds but then tries to get away
  4. May wiggle for a few seconds but then stays still
  5. Stays still and relaxed, does not mind what is happening

(Azriel can be a 3, 4 or a 5 depending on how silly/sleepy he’s feeling)


Test 6: Noise
Clap loudly and watch the rat’s reaction.

  1. Jumps, runs around, climbs walls (general panic that does not stop within 10 seconds)
  2. Jumps of freezes and then finds a place to hide, does not come out within 30 seconds
  3. Jumps of freezes but recovers when touched, distracted, or reassured
  4. Freezes, but only for a few seconds and recovers without interference
  5. May freeze or pull back for a second but then comes over to investigate

Test 7: Unfamiliar area
Place the rat somewhere it hasn’t been before (either in another room of the house or, preferable, outside somewhere you know it will be safe)

  1. Jumps, runs around, climbs walls (general panic that does not stop within 30 seconds)
  2. Searches out hiding places or huddles in a corner
  3. Becomes clingy, looks to a person or another rat for comfort
  4. Cautiously explores
  5. Confidently explores


Test 8: Food manners
Offer the rat a small amount of food (try with both wet and dry food) from your fingers.

  1. Bites on purpose (not because it is mistaking your fingers for snacks)
  2. Takes the food carelessly biting your fingers in the process, or runs away scared
  3. Sniffs the food but may be too nervous to take it, or snatches and runs
  4. Cautiously, but gently takes the food
  5. Confidently comes up and gently takes the food

Test 9: New rats
In a neutral area, introduce the rat to another of the same sex and observe its reaction (to make this a fair test it’s better to try this with a new rat that you know plays nice with others)

  1. Attacks or acts extremely aggressively
  2. Puffs up, crab walks, acts defensively but does not actually attack
  3. Runs to a person for comfort, or runs away
  4. Sniffs and then ignores the new rat
  5. Sniffs and takes friendly interest in the new rat

Test 10: New people
Get someone that the rat has not previously meet to handle it. They should try picking it up, patting it, allowing it to sniff their hands etc.

  1. Attacks or acts aggressively
  2. Is excessively wary and mistrusting, struggles to get away when held
  3. Acts somewhat wary, wont approach the new person but allows them to pick it up
  4. May be a little wary but allows the person to touch and pick it up without resisting
  5. Sniffs and takes friendly interest in the new person, is relaxed and trusting when picked up

The maximum a rat can score is 50. A nice, friendly rat should score at least a 4 in most categories though there are some (like lying back) that are harder for most rats to score highly in.


Rats are social animals and need to live with at least one friend. However, it can sometimes be a bit of a process introducing a new rat to into a group. I have found that, usually, new rats are happily living with the others within a few days, but sometimes it can take a few weeks to get them settled, and I know of some rattie combinations that have taken even longer to become comfortable in the same space.

Here is what I do when adding a new rat to my group.

Step One: Put the cages side by side but not so close that someone could get bitten through the bars. They should be interested, but not super aggressive.

Step Two: Switch the rats into each others cages to let them get a good sniff of their future friend.

Step Three: Allow the rats to meet in a neutral area (out of their cages). Watch for any signs of aggression, particularly from the dominant rat. Some people do this in the bathtub but my rats are a bit scared of being in the bath so I let them all meet on the floor after making sure there’s nowhere they could get lost or stuck. It’s a good idea to have a towel handy in case you need to break up a fight (an aggressive rat might bite you without thinking about what it’s doing, so be careful). Hopefully the rats are interested in each other but not violent. The new rat may squeak when it’s approached by the others, and the others may try to roll the new rat onto it’s back. If the new one starts looking terrified, put everyone back in their cages, let them look at each other through the bars, and try again the next day. After they’ve been together without anyone getting too mean for at least 30 minutes you can move on to the next step.

Step Four: Let all the rats hang out in an area your original rats usually play when out of their cage. Watch for your dominant rat showing sights of aggression – an arched back, raised fur, ‘crab walking’, or chattering. Put the rats on your knee or on your shoulders to get them close to each other and show the others that you like and accept the new rat. If they can go 30 minutes without a problem they are ready for the final step.

Step Five: Give your cage a really good clean and rearrange things a bit so that it feels like a new cage and not your original rats’ territory. Put the rats in the clean cage and watch closely. You’ll probably see the new rat being flipped over and pinned quite a bit, as well as being held down and licked. You may hear squeaks as they sort out a new pecking order.  If you see the new rat constantly being chased around the cage, or you think the fights are too rough, move the new rat back to a separate cage and redo step four. Most of my newcomers have picked a ‘safe’ place in the cage and have mostly hung out there for a day or so. I make sure that they have easy access to food and water from their chosen spot and avoid feeding anything too delicious for a few days to lessen the risk of food related arguments.

Usually I can get through step one to four in a day and complete the process the following day. Having a big-ish group of rats and a big cage means no one cares that much when someone new moves in. My dominate girl has her hands full keeping everyone else in line so she doesn’t have a lot of time to terrorize newcomers. However, it can take much longer so be prepared to take it slow if you need to.