geez, it always seems to come back to the old "space issue" eh? sure, i can understand that it costs a reasonable degree of money to build even the simplest of tiger or great ape enclosures and this doesn't take into account the space that it takes up. however small mammals such as porcupines, bilbies, otters, agouti, patagonian cavies, marmosets, loris', tamarins, even tree kangaroos and binturongs are all very easily accomodated. i would like to see the zoos take one years time out from immersion exhibit building - just to spend the annual budget for such instead on building facilities, off exhibit if need be, to hold larger populations of so many of these species. it seems the apparent "lack of space" is just far too much a constant compromise on breeding programs for the issue not to be addressed in the short-term.