[narby]

How would animals know it was warmer in the south?

How to geese know to fly south in winter?

Yes, mass extinctions occur, sometimes during climate changes. But rarely are those changes so swift that the normal year to year ranges of creatures won't gradually shift along with the climate.

You're grasping at straws, attempting to find problems for evolution. In 150 years, don't you think somebodys tried that attack on evolution yet?

[metmom]

Geese migrate because it's natural for them to do it. Migrating on instinct is not the same thing. I don't think those little goose brains think, "Oh, it's getting colder. Time to head for FL."

It's not natural for many other species to migrate and there would be no way for them to *know* that heading south would be warmer. It certainly isn't around here, the areas slightly to our north are virtually always 3-5 degrees warmer that the hills and mountains we're in to the south, so there would be no incentive to head in that direction *looking* for warmer climates.