Tepig's body design is most likely based off of a baby Japanese wild boar.
Tepig's Japanese name is derived from ぽかぽか pokapoka, warmth circulating through one's body, combined with 豚 buta, pig; or ブー bū, "oink". Its English name comes from "tepid" and "pig".
Tepig is the third starter Pokémon to be a mammalian, with the first two being Cyndaquil and Chimchar. It is also the third Fire-type Pokémon to be mammalian, continuing the trail, though it is broken by the Water-typed Otter Pokémon Oshawott, both in the same region.
A silhouette of Tepig, Snivy, and Oshawott was released on May 9, 2010 during an episode of Pokémon Sunday. An actual photo of the three starters was shown in an issue of Cocoro magazine on May 12. It was shown again on November 22 for the official English names.
Tepig is the only Unova region starter to be quadruped, being that Oshawott and Snivy both walk on two legs. When it evolves into Pignite and Emboar it walks around on two legs as well.
Tepig is the only Unova Starter to gain a second type as it evolves.