Vocenoctum said:
Taking your logic though, the halflings are quite silly to live in the plains. They should be living in the jungles where their Mutant Powers would be beneficial.
Perhaps. But personally, I think you're overestimating both "mutant powers" and the effect culture has on racial statistics.
A halfling receives a +2 Dex and -2 Str. These are biological factors. It is a small creature incapable of lifting much weight.
A halfling receives a +2 to Climb, Jump, and Move Silently. This is described as being due to the fact that halfings are "agile, surefooted, and athletic" - not because "halflings are trained in stealth from an early age and perform regular calesthenics". In my opinion, this is a PHYSICAL trait - not a cultural one. With a -2 Str modifier, a halfling would normally suck at both Climb and Jump. This bonus says that not only do they not suck, they're actually sure-footed and quick. Their build is ill-designed for carrying heavy loads, but they are better climbers than raw strength would account for. An alternative approach would have been to allow them to use Dex instead of Str for Climb checks, like a monkey. I believe that the "monkey build" is what we're dealing with - one of the differences between gnomes and halflings, both small creatures with a -2 Str. Gnomes are small and stocky, receiving no bonus to physical skills. Halflings are quick and agile, making them better at climbing and jumping and much better at moving quietly (having both the racial bonus and the Dex bonus).
Tied to this, we have the +2 to Listen checks, because they have "keen ears". Personally, I take this to mean just that: the halfling sense of hearing is better than that of a human. Do you think that's the case, or that halflings are trained to eavesdrop as kids? A racial bonus is something that is possessed by all members of a race, regardless of how or where they are raised. Thus, I would assume that the Climb bonus is EXACTLY the same as the Listen bonus - the result of a physiological difference between humans and halflings, or halflings and gnomes. it doesn't matter if they grow up in the jungle, the city, or the plains - their build is well suited to climbing.
Now, a halfling in the Talenta Plains is more likely to take SKILL RANKS in Ride and Handle Animal than many other characters, because he encounters those things on a regular basis. But he has that bonus to climb whether or not he ever does climb, because it's part of who he is. A racial bonus to Ride would mean that all halflings are skilled riders, regardless of whether they grew up in the Talenta Plains, Sharn, or in a family of humans - and that seems like far more of a mutant power than having a build that's weak but agile.