Baby gerbils could be weaned by 4-5 weeks, some larger litters will take
longer and some babies just don't mature as fast. If the mother doesn't mind
the babies sitting around with a new litter you might as well leave them.
There can be problems with 2 litters, some of the problems I have encountered
over the past many years are: a female that would always abandon the new
litter if old babies were still in the cage, a female that would chase bite
and eventually kill the older litter before the new litter was born. In each
of those cases I had to remove the babies at 4 wks to ensure no one died,
these are both fairly uncommon but can happen.
Doug
