I'm looking for a story that I remember reading approximately 10-15 years ago, but the story itself is older maybe from the 60's/70's. The story was written in English and was in a paperback, possibly an anthology, but I don't remember any of the other stories if it was.
The details for this one story are a little vague but what I remember is as follows:
A spaceship is orbiting a planet and notes that there is nothing showing on any scanners except for a thin line of heat being around the oceans. As this seems to be the only evidence of activity on the planet and is unusual, one (or more) of the crew land inland of the "heat" line and set out to find out what it is.
As the crew get closer to the source of the heat signature they begin to see skeletons and then dead bodies. I think the ending has the crew crest the top of a hill and they see that the source of the heat signature..... all the humans/humanoids that make up the population are crowded around the shores and have evolved to be taller to try and reach the ocean. They fight and kill each other to reach the water I think
I remember the sense of quiet desperation of the story and would like to read it again, can anyone in the community help me with an answer to this question?