[medved]

That's a good question and in the particular case of the trex I couldn't rule it out on first principles. Some scientists still think sauropods lived in water since the square/cube problem is insurmountable, but that doesn't work for numerous reasons. A sauropod might get floatation in the center of a lake but there'd be nothing to eat there; he'd have to come to the edge of the lake to try to browse on vegetation growing there and, the first minute he did, his feet would go straight into the muddy lake bottom around the edge and he'd be stuck there for the rest of his life, which would be about two days starting from then.

Moreover, an adult elephant requires about 25 square miles of vegetation to eat on a yearly basis and a sauropod would require much more than that, and browsing around the edge of a lake wouldn't provide that kind of square mileage even if you forget about the problem with not having snowshoe feet.

[TigerLikesRooster]

Re #14

The picture of sauropod I saw has a long tail. Could this tail be used as swimming aid ? Besides, if the animal lowers both its tail and neck on the surface level of water, it can get good buoyancy in shallow water too. That way, sauropod can slither out of muddy shore like a semi-snake with fat mid-section. By the way, another possibility is that sauropod eats not leaves and trees but algae-like micro organism on lake surface. It is like one of those large whales or giant sharks which suck in huge amount of water and eats micro-organisms. If sauropod have similiar diet, all it has to do is sucking water and filter algae all day. I am not sure how well its teeth were develop. If they are not well-developed, we can say sauropod is scum-sucking all day and does not have to worry about navigating lake or land with that inconveniently shaped body. Sauropod looks to me an animal who do not want to go anywhere in a hurry, stays in one location most of the time.