@PAT They really do make for a fabulous exhibit. I dream of the zoo importing an unrelated male (the two brothers have been sterilised I believe), and housing a functional breeding group again. They're stunning monkeys, and their exhibit has to be one of the very best for primates in the region-- a shame it's just the four siblings up in that massive tree now.
Spectacular photo @marmolady . After seeing the group of ten François' Langurs at Taronga last year, it really made me think that langurs need a much stronger presence in our zoos (like virtually every other Old World monkey).