Do you really need the money?
If not, then hold onto the name. Chances
are if one person is interested then more would
be. The name has two good key words for an
animals/pets category, the hyphen is a drawback
but it's still a dot com.
You could make a nice animal website or forum out of a
name like that.
I see you've already given a counter offer, so if
they accept I guess the sale is done. But if
they say no then hold onto the name for more down
the road.
I'm not a big fan of selling good domain names for cheap
prices, the exception being if you need to raise some quick cash.