Alto is technically the highest male voice, which is higher than contralto. I know a couple of mature males who fit that category of voice.

I always thought I was contralto because I used to be able to really belt it out in the lower ranges, which most females I knew couldn't even reach. My high notes are hugely squeaky since they mostly disappeared when I was 12-13. But my voice is lighter in feel than contralto. *shrug*