What could be the cause of dandruff?

[purinpurin]

I saw a little bit of reddish "dandruff" on Loki's back last week (which went away when I bathed him), but it hasn't appeared since then. After consulting Chelle, she said that it was most likely lice, which I thought it was as well, and went to a vet, but he said it wasn't lice or mites, and that there isn't anything wrong with my four boys (I adopted two rats from Chelle early this month XD).

There doesn't seem to be anything wrong with Loki now; I don't see anything on his skin, nor the "red dandruff"-like things that I saw before.

Does anyone know what the cause might have been? I'm thinking of some possibilities, and I did give them crushed watermelon and cherry tomatoes the day before I saw the dandruff, but I'm not quite sure how it could possibly get on Loki's back... And one of my other rats (Sodapop) is also light-coloured as well (a fawn), but I didn't see anything on his fur.

So, I'm just a tad curious now, haha.

 

[DadRat]

Was it a yellowish color? Might just be some excessive buck grease from the little man.

 

[jorats]

Older rats may develop dandruff like flakes but like us, they're white in color.
Some males also get excess sebum like DadRat has mentioned.
Or, what I think it may be in this case... Porphyrin on the ends of the hair. That would explain why it washed off. However... Porphyrin does not appear as flakes but rather a coloration.

 

[purinpurin]

Ahhh, I see, thanks for the inputs. I guess maybe the porphyrin got on his fur, dried out and when he scratched himself, it fell off...? It sounds a bit far-fetched, but that's the best explanation I can come up with now. ;;

I also got a kitchen scale today and weighed them all... I can't tell if they're "fat" or not. I don't want them to be overweight as obesity isn't good in any species, so I'm wondering if I should cut down on the fruits. What are some signs that a rat is getting overweight?

Loki (approx. 3 months old) - 270g
Indy (approx. 3 months old) - 255g
Dallas (born on April 2nd, 2011) - 145g
Sodapop (born on April 2nd, 2011) - 155g

 

[jorats]

At their young age, I wouldn't worry about them being fat. And don't go by the scale right now because they are still growing and each rat will grow at their own rate and their particular size.