Why do my pet rats do this?

I have two “medium” brown rats, not sure the type, both female. Their cage is of average size, with “a loft” that adds a small second floor, sort of. The food cup covers a circular hole in the loft. After they eat, they put bunches of their bedding on top of the leftover food. They have to go up a ramp to do this, so it can’t be an accident. The bedding I use is the leftover shredded paper from work- I know, not the best choice for bedding, but my job has tons of it- I’ll buy some of the good stuff when I get some money. But why oh why do this? I obviously did not use the right search words on Google…

They’re probably trying to bury it.

They are conducting an experiment on you to see your reaction.

Oh, I see you’re confused. Look, we experiment on them. Get it?

Maybe they’re hiding it for later.

Rats hoard food. Which is one reason why fresh food has to be carefully watched, in case they hoard it and it then goes bad.

Is there newsprint on the paper? Or is it blank? Newsprint= bad. Blank = OK. Other printing= I dunno.

Possibly Rat defensive behavior: burying noxious food.?

Is it a new brand of food?
Do they ever eat it once they’ve covered it?

Yep, they’re hoarding. Just muck it out regularly so it doesn’t spoil.

About the paper - newsprint isn’t all bad. Our local papers used vegetable based ink. I know because I called 'em and asked. Just avoid anything oil based. Offhand I’d say thoroughly dried printer ink should be okay, as long as it doesn’t come off on their fur.

The best thing is hay. They can eat it and sleep in it very comfortably. Just keep an eye out for fleas and mites if it’s been exposed to wild rats.

Yeah, that’s what they want us to think.

I, for one, welcome our new rat overlords.

They also think if they hide it and you can’t see it, then you’ll give them MORE.

I’ve done this-- open the cage door, start passing out treats one per rat, and all of them run off, hide the treat, and then come back all innocent and starving-looking. “Please give me a treat, I haven’t had one…I’m a totally different rat who looks the same as that other rat you gave a treat to!”

That’s what they want you think.

This is normal hoarding behavior (behaviour). Laboratory set-ups deal with this behavior by feeding blocks of rat chow that are suspended over the animal. The rats eat the food through the grate.

My rat had a similar behavior: she’d finish the food in her bowl and then fill the empty bowl with shavings. Sometimes she’d bury the food elsewhere if she didn’t finish it, but she’d still fill the empty bowl with shavings.

–FCOD