The Muppets are a veritable cornucopia of different species. Some are obviously Muppet versions of humans, like [Statler and Waldorf][1]...

[![enter image description here][2]][2]

... although it appears there's a distinction to be made even between a Muppet version of a human and an actual human, judging by the song _[Man or Muppet][3]_ from _[The Muppets][4]_ (2011).

[https://www.youtube.com/watch?v=cRTjksM3YAs][5]


As for other Muppets, some are apparently meant to belong to other subsets of the animal kingdom, like [Kermit the Frog][6], who's been clearly identified as a frog at various times, like in _[The Muppet Movie][7]_ (1979) (credit to PlutoThePlanet for this one), or a more recent interview with Ellen DeGeneres.

[https://www.youtube.com/watch?v=2fwq7YY2Suc][8]

[https://www.youtube.com/watch?v=1_AUn5poOmA][9]

Some are clearly identified as fruit or vegetables:

[https://www.youtube.com/watch?v=OuB4Jfw5n_8][10]

And some are altogether alien, like [Gonzo][11], whose extraterrestrial origins were revealed in _[Muppets from Space][12]_.

[https://www.youtube.com/watch?v=Lx2jYCltuQo][13]


  [1]: https://en.wikipedia.org/wiki/Statler_and_Waldorf
  [2]: https://i.sstatic.net/0ZVoU.jpg
  [3]: https://en.wikipedia.org/wiki/Man_or_Muppet
  [4]: https://en.wikipedia.org/wiki/The_Muppets_(film)
  [5]: https://www.youtube.com/watch?v=cRTjksM3YAs
  [6]: https://en.wikipedia.org/wiki/Kermit_the_Frog
  [7]: https://en.wikipedia.org/wiki/The_Muppet_Movie
  [8]: https://www.youtube.com/watch?v=2fwq7YY2Suc
  [9]: https://www.youtube.com/watch?v=1_AUn5poOmA
  [10]: https://www.youtube.com/watch?v=OuB4Jfw5n_8
  [11]: https://en.wikipedia.org/wiki/Gonzo_(Muppet)
  [12]: https://en.wikipedia.org/wiki/Muppets_from_Space
  [13]: https://www.youtube.com/watch?v=Lx2jYCltuQo