
First and foremost you have to make sure what ever you use to help keep them cool will not be toxic or a danger to them in any way.

- (UPDATE EDIT 7/26/2020) I never found the sweet spot for filling them with water because a few still broke even if half full. I now put smaller plastic bottles in freezer but then put the frozen bottles into the larger glass jars works GREAT!) I fully expect my husband to come home and question me as to why we have a half of dozen glass jars 3/4 full of water in the freezer. My reasoning is, even though we have a couple window units in our home, a malfunction could occur, or there could even be a power failure. I choose glass because I stick them in the cage and do not want my chewers to cause a flooded mess. If my a.c. doesn't work well enough on the triple digit days, I will put a couple of them in the cages on different levels so the ratties can snuggle up if they are too hot. (Make sure to leave a few inches from the top of the jars when filling with water, I also leave the lids off the jars until I take them out of freezer to be extra safe - water expands when frozen)
- We also have several marble tiles for the rats to lay on (or rather puddle on like they have melted) These I can rotate in the freezer as well. Though the marble is the same temp as the surrounding air it does feel cooler to the rats because it is more efficient at absorbing their body heat. Pulling them out of freezer/fridge will give them the quick option to cool off even more.
- Freezing peas, fruit and other goodies into ice chunks for the rats to chew and eventually splash in to stay cool. It is pretty funny watching a rat pull an ice cube out of bowl and drag it up to their hammock to chew and cool off.
- We have also misted their tails with cool water to help keep them cool.
To begin with, rats cannot sweat nor do they pant to release heat. They actually use their tails as a thermal-regulator. Here is a great link that talks about how that works. The rats will begin to show signs of being too hot at around 80*+ This is when they start to lay flat on the shelves spreading out to help cool themselves. At above 90* the rats will be extremely uncomfortable and will need you to provide extra cooling relief. If your home hits above 104* the rats could actually die from the heat. These are in the case of a healthy rat. If you have a rat that is older, obese or struggling with URIs they will be even more sensitive to the temperature fluctuations.
Things to look for:
- Puddle Rat - This really needs a visual but I do not have one. If you have ever seen a rat melt onto a surface you will know what I mean by Puddle Rat. This is when they lay on a flat surface, spreading out all of their body trying to get cool.
- General lethargy and slow movements - Our rats are all over the place normally. Like us, when they get hot, they really do not want to move around. This is the first warning sign that your rats may be getting overheated.
- Stop eating and/or begin drinking excessive amounts of water - Like us, as they overheat they will crave fluids at first.
- Their Tail, Nose or Ears become hot. I have only read this. I have not experienced this. Make sense to me those will become hot in the event the rat is becoming overheated.
A rat's condition can turn quickly. If your rat actually goes unconscious from heat stroke, this is considered an EMERGENCY, your rat can die! You will need to immediately cool it off and call your vet for EMERGENCY help. To cool it off, I have read first thing to do is to immerse the rat up to its neck in cool water (NOT ICE). Do not submerge it's head.
I hope NO ONE has go through this, which is why I am also including a few links and other ideas I have seen online to help keep the rats cool!
*Keep your rats on the lower levels of your home*
This goes almost without saying. However, the lady I mentioned above had her rats in the upper story of her home. If it is too hot for you it is WAY too hot for them!
*Fans are great but do not blow them directly on the rats cage*
Rats have very sensitive respiratory systems, the constant air on them may dry out their nasal passages and/or stir up excessive debris in their cage that can get into their lungs.
*Make a rat air conditioner over a shelf or hammock (According to several people this works well)*
Ice Packs (if above the cage out of their reach)
IF doing this on a shelf in the cage make sure to use glass jar of frozen water
A smaller mixing bowl or small plate
A larger mixing bowl
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Put ice container in small bowl/or small plate
Set small bowl over cage (or on shelf) where there is a hammock below it.
Place the larger bowl upside down over the smaller bowl/plate. This allows the cool air trapped in the larger bowl to flow down to the hammock directly beneath it.
*A link to make your own A.C. for around $8.00*
*Cover your cage with towels and keep them wet (warning they will get chewed and pulled in)*
Hope this all gives you some ideas on how to keep your furbabies cool!