I have been trying to find a story that I read 20-25 years ago in a science fiction anthology about frontier planets. In the story, a big game hunter has come to a planet to hunt the most dangerous game. He goes to a bar to hire a guide. There is a trophy of the animal over the bar, a small wormlike creature. What makes it so dangerous is the fact that it is normally shape shifted into a large lion like creature that lives in packs. The hunter hires a guide who takes him out and over the course of the hunt tells him stories about the creature and other things. The hunter realizes that the creature he is hunting is actually highly intelligent and telepathic and if rejected by his pride will end up dying of loneliness. Unless it ends up shapeshifting into another form and forming other telepathic bonds. He also realizes that his guide is one of the creatures that has done just this.
A story with some strong matches and some strong mismatches is worth an answer, in case memory distorted or conflated some scenes. (It is a good story in its own right too.)
Thinking that some details make "Hunting the Snark" by Mike Resnick a mismatch, here are some of the matches:
"a big game hunter has come to a planet to hunt the most dangerous game."
He is an employed safari leader:
At that time I worked for Silinger & Mahr, the oldest and best-known firm in the safari business.
We pros wanted to hunt new worlds every bit as much as the clients did.
"He goes to a bar to hire a guide.”
He hires several guides native to the planet, best tracker among them Chajinka.
The twelfth was my regular tracker, whose name–Chajinka–always sounded like a sneeze. "Ugly little creature," remarked Mbele, indicating Chajinka. "I didn’t pick him for his looks." "Is he really that good?" "The little bastard could track a billiard ball down a crowded highway," I replied. "And he’s got more guts than most Men I know."
"...to hunt the most dangerous game..."
It proves itself the planet's most dangerous lifeform when necessary:
He paused. "An entire family of brown cats–at least four, perhaps five–fled from a single animal that hunts alone." "You’re sure he’s a solitary hunter?" He studied the ground again. "Yes. He walks alone. Very interesting."
"The hunter realizes that the creature he is hunting is actually highly intelligent and telepathic...."
He finds out:
I felt something like an electric surge within my head, and suddenly, though I’d never experienced anything remotely like it before, I knew I was in telepathic communication with the dying Snark. Why did you come to my land to kill me? he asked, more puzzled than angry.
“…. and if rejected by his pride will end up dying of loneliness.”
Well, with telepathic contact he finds out -- everything:
. . . because he wasn’t a he at all; he was an it. The Snark was an asexual animal that reproduced by budding. Its final thought was one of enormous regret, not that it would die, for it understood the cycles of life and death, but that now its offspring would die as well.
As for the mismatches: there is no trophy over the bar; it has been a long time since I read it but I have found no reference to shapeshifting. And although the lifeform was so dangerous it scared off entire prides of lions or big cats, and although Chajinka did pick up a large worm and eat it, these were parts of the story and not aspects of the lifeform.
But, memory can distort and conflate some details. So there is a story that may or may not be a match.
I found two published anthologies called "Frontier Worlds" on ISFDB. Neither of them contains "Hunting the Snark", but the story titles in them look like one of them could match the question, if "Hunting the Snark" is not it.