The better half and I went to the Zoo on monday, you can go in through open gates on the south side of the Zoo.
The pics on page 2 of this thread are quite a contrast to the ones I took on monday.
tiger enclosure
folder with all the pics I took, theres nearly 60 pics, all worth a look at, any questiosn just ask.
http://www.renault-turbo.com/chris/glasgow%20zoo/
The place is a real state now, when we were there tyres were still smouldering beyond the tiger enclosure.
If your a female I would advise you not to go alone.
People ARE living there between the bear enclosure and the old gift shop.
There are also a lot of neds there, monday was a bank holiday so probably that made the ned count higher.
Some of the zoo just ends in the construction yards so you need to turn back.
I would advise seeing it now before its all but gone.
Parts beyond the tiger enclosure and the 'lagoon' filled with tyres are pretty quiet as they are out of the way. However its a bit rough so don't break your leg or anything.