Frankie

Question
I got my pet rat Frankie 9 months ago, he was a half hairless rat, not a full breed.On the same day I got another hairless rat. They were both baby boys and they were in the same cage until i noticed that when they got older they started fighting alot. Frankie had scratches all over him, so I separated them. Then i noticed that Frankie's head had a strange tilt to it. it didnt seem to bother him and he was still healthy as far as I knew... I called him crooked head. So about 7 months later I woke up one morning and Frankie was laying on his side dead. The previous day he slept a little more than normal and would only respond to me after I woke him up, when normally all i had to do was say his name and he came to me. But once he woke up he was eating and drinking normally.Then the next day he was dead. What couldve happened to my rat. He was loved very much and seemed to be very happy. it doesnt make any sense.

Answer
A 'half hairless' is not a variation type. Some hairless varieties have a thin layer of coat, and there's also double-rexes that have a short, thin, soft coat. A rat can carry hairless and be furred or be hairless but half hairless is an incorrect term - it's like saying you're half straight haired or half brunette. Was he hairless/naked, or did he have fur?

When puberty hits male rats, they often vie for attention and cage space and can begin fighting pretty bad. More than likely, Frankie kaboshed his head and injured either his neck or his brain itself, causing swelling and that head tilt. Hairless rats are more prone to injury and fragile, and over time, their head tilt can begin to worsen until eventually they're just a shell of their former self.

However if you noticed nothing out of the ordinary until he was 16 months old and then he just died, it may have been something entirely unrelated to the head injury - like heart disease, respiratory failure, liver or kidney failure, etc. -- there's really no way to be totally sure without a necropsy. The sleepiness the day prior sort of indicates to me that it might have been a sort of organ failure.

I'm sorry for your loss!

Edited to Add - I'm sorry if you feel like I stepped on your toes with that; that wasn't my intention. My intention was to clarify whether he was in fact a hairless or a furred, considering that hairless are considerably more fragile than furred. I'm sorry for not phrasing it better, it wasn't my intention to hurt your feelings or irritate you -- but thanks for making me feel like an ass.