Ask your guide: how long are the elephants chained for?
It's a sad fact of life, but any elephant in captivity - whether they are working in tourism or are in a sanctuary or orphanage, has been 'domesticated' and therefore cannot return to the wild. This is also because much of an elephant's natural habitat has vanished.
As large, wild and incredibly powerful mammals, they need to be confined for their and humans' safety. This often means they are chained up for some or the majority of the time (depending on how ethical the venue is).
An elephant ideally should only be chained at night, when their mahouts are sleeping. During the day, eles ideally would have the ability to roam, forage and socialise (with their mahout close-by) and only being chained when they are a risk to themselves or others.
This is why we recommend tourists don't bathe elephants, as the ele is often chained up in between baths, then walked to and from the same spot all day every day.