I think they are both based off of the same Japanese legend, hence our Pokemon Ninetales and the Naruto nine-tailed fox. Same reason why there is an Entei in Inuyasha too - it's all about the Japanese culture and its legends having an influence on the Anime of Japan.
Wasn't there some similaries like this with digimon and monster rancher? It has been a while so I can't remember because I have only seen those shows a few times.
I thought there was a resemblance but I never gave it a second thought, that clears that up. Also "Digimon" and "Monster Rancher" shared some similarities but jeez there were both just bad and I'm glad there both not as 'popular' as Pokémon.