Students caught a Walking Stick

Hello,
My students (kindergartners) found a walking stick yesterday while we were on the playground. They insisted that we take in because they were certain it would freeze to death outside. I called around to some petstores and they informed me that he/she would eat rose petals and small crickets. We have it in a large tuperware container with Plastic Wrap over the top with small holes for air. My questions are, can you tell if its a boy or girl? And what kind of substrate should I use for his enclosure? I figure he/she won't live long in captivitiy, but its probably longer than out in the freezing cold weather.


Tracie
Kindergarten teacher Extraordinaire