No your pocket is not the best place for your furry little friend to reside. I have been looking around for suitable cages for gerbils in particular. As they like lots of sawdust they tend to flick it out on the floor everywhere which is very tiresome to keep cleaning up, as they are small burrowing creatures. This cage is a good one for both hamsters and gerbils, gerbils especially as there is ample space and hidy holes for little curious burrowing creatures to feel perfectly at home . This cage is large and very spacious with lots of different huts to hide out in. The levels and houses are made out of good, which is good for both their feet and for chewing without the fear of your critter becoming sick.
Additionally there are lots of toys available that your gerbil or hamster can safely chew and gnaw till their little furry hearts content.