Orange mice? I never have seen an orange mouse, though some can be beige or tan. Most I have seen are not solid colored in tan or beige, other than a more tan looking agouti type color/coat.
The only yellowy/orange rat I have seen turned white once it was full grown and turned out to be a siamese point white/charcoal grey points.
Personality wise, rats are more easily handled than mice and more intelligent. Mice tend to be more skittish when handled but can be tamed down and will calmly walk and climb all over you. They do have the annoying habit of going to the bathroom all over you. So far I have not heard of anybody able to train a mouse not to do this. Rats however, can be easily trained not to eliminate on you. Most just do it naturally, once they get over their initial nervousness (even when nervous they tend to only poop). Male rats will 'dribble' urine as they walk but if you don't mind a few spots of urine on your clothes, then it's easily tolerated. Females don't do this dribble thing that I have noticed.

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PHLdyPayne