Are Earth Pony, Unicorn and Pegasi seperate sub-species?

[SteveMorison 404]

A subspecies is a category of at least 2 of the same species but still some very distinct anatomical features. Don't normally breed together but is possible.

[colt_following 169]

Are they not just different 'races' under a single species, like humans? Or (without my attempt to Google this) are 'subspecies' basically the same as 'races'?

 

I'm a human, but unlike many other people, I have dark skinned, a wide nose and nappy, knotted hair, but I guess contextually we don't have subspecies.... I dunno. NOW I'll Google it cuz I'm curious.

[cider float 2,535]

In Hearth's Warming Eve they are described as tribes. Tribes can mean anything nowadays in the fictional world but most of the times it's groups with different cultures and nationalities.

[Concerned Bystander 2,901]

There is clear evidence of interbreeding between the various pony tribes/races.  The Cake's children for example, both of the older cakes are Earth Ponies but they have one Unicorn child and one Pegasus.  They explain this in an episode that somewhere in their ancestry there was a Unicorn on one side and a Pegasus on the other, I forget the exact details but I remember it being covered.

 

So they are clearly all the same species, but but clearly each of the three is distinct from the other two.  It would seem that the Unicorn horn and the Pegasus wings are a dominant genetic feature as there doesn't appear to be any hybrids as such, unless of course this is why Scootaloo has such tiny wings and is unable to fly?

[yisetab28 89]

I'd say they are like dog species. They're actual different races, but of the same species. Saddle Arabian horses/ponies, actual horses and the 3 types of ponies may be subspecies of an equine species.

[Kyoshi Frost Wolf 40,304]

I would consider them more like races, which I suppose would honestly be the same thing almost. I say this because of what Concerned Bystander pointed out, the fact that the different pony types can inter breed. That is pretty much the best indicator to me.

[manic 121]

Definitely more like races, prime evidence is the Cakes.