[Jack Garcia]

They make good pets, but they have some special needs. To do well long-term, they need a heat lamp and a slightly different diet (higher in protein if I remember correctly). I traveled with about a million of them (or so it seemed) to the last Rodent Fest. They are weird but cute little critters.

 

[Jack Garcia]

It's also more difficult to sex them, as males aren't as "gifted" as are normal male mice. It's also harder to neuter them. I know a male spiny who was (supposed to have been) neutered but then got his cagemate pregnant!

 

[Jack Garcia]

I didn't have any problem sexing mine.
The males I've seen, have a dark patch on their testicles, so it's pretty easy to identify males from females, even when the 'bits' are pulled up inside.

Yeah, my impression is that pulling them up inside is what makes it difficult to sex them sometimes, as females can have a dark genital area, too. It's also what makes them more difficult to neuter than regular mice: even when they're unconscious, they pull their testicles in!

It's a side-effect, I think, of cold temperatures. At least, it feels cold to them. If you keep them warm, it's easier to sex them but of course all operating rooms are naturally cold to prevent spread of germs.