One of the Major Systems of Nature is the constancy of Change. In big ways, in small ways, things are moving forward, or backward, or wayward, but that is how it is.
An element of this policy is that there will be many hellos for a Rhino. And many goodbyes, however dear and essential those folk or places may have been.
Change is not always easy. Sometimes it hurts or seems unjust. But no Rhino is exempt.