Although all but unknown in the lands north of Hoenn, Taillow are known throughout the tropics and subtropics as the great colonists of the pokemon world. There is no warm island known in the pokemon world large enough to contain a tree and worms which Taillow have not once roosted on. Although they are often driven out by more powerful native pokemon, the courage with which they fight has often allowed them to establish themselves as one of the most common pokemon of the area; wherever they are expelled from by superior predators, they will always return to fight for food and pride another day.
Even in this age of stable climates, the journey of an individual Taillow can be easily mistaken for that of the great naval explorers of old; most can claim to have circumnavigated the earth at least once. But in times when Heatran filled the sky with volcanic ash that blotted out the Sun, Taillow could find nowhere to land. In these awful years, they flew through the freezing cold like Delibird, carrying flame orbs and growing stronger for them until they landed where they could find warmth, in Sinnoh near the very mountain where Heatran had erupted.
It was these journeys which carried Taillow as far north as Sinnoh, and many other pokemon to boot. Taillow are known for eating eggs and seeds, but their digestive system often does little more than drain a few nutrients, leaving the pokemon inside very much alive. Likewise, the larva of many bug pokemon cling to them as parasites.
The Poke Radar of Sinnoh operates by using traces of Taillow DNA to find the rare and foreign pokemon they introduced to that land which have spread beyond Stark Mountain and the Battle Zone.