At jersey zoo they are just left to roam around the forest. That is good for the animlas as they have a very large area but bad for the visitors as you can't see them. It is ironic that a smaller zoo such as Jersey gives it's tamains larger areas than london which must have more than 20 times the budget of Jersey./QUOTE]
I doubt whether free-ranging Tamarins/marmosets would work at a big Urban Zoo like London- they would possibly get stolen in no time at all! Jersey has overall a very different sort of visitor to London Zoo- mostly older people and genteel holidaymakers so there is a more 'cultured' and relaxed atmosphere and little risk of theft there. City zoos tend to have a higher percentage of the type of visitors who are likely to get up to mischief.