In The ManTrap, nothing was said directly (as I recall) about salt being at all available on the planet's surface. For all we know, there may be dried ocean beds or some such sources. My question is: even if they had dumped the creature in some such place on the planet, with enough salt to last it the rest of its life...well, it would HAVE to need SOMETHING else! I have no idea what that would be, other than maybe some water? How could anything live on one thing?