Are pure-bloods actually a distinct species from Muggles?

Question

From this question I note that pure-bloods are not actually really pure blooded according to the following quote:

“So-called pure-blood families maintain their alleged purity by disowning, banishing, or lying about Muggles or Muggle-borns on their family trees. They then attempt to foist their hypocrisy upon the rest of us by asking us to ban works dealing with the truths they deny. There is not a witch or wizard in existence whose blood has not mingled with that of Muggles, and I should therefore consider it both illogical and immoral to remove works dealing with the subject from our students’ store of knowledge.”
_{^{- The Tales of Beedle the Bard}}

One of the answers also notes that pure-bloods generally lie about Muggles or Muggle-borns on their family tree so that they can give the illusion they are pure-blood. Although the other answer notes pure-blood may actually just mean no Muggles of Muggle-borns within X generations.

However, this led me to an interesting thought: was there ever a time when there was a witch and/or wizard who was truly a pure-blood i.e. no Muggle of Muggle-born in their family tree? If this is the case does that mean witches and wizards are technically a separate species from Muggles?

Answer 1

It’s very likely they aren’t distinct species.

It seems almost certain from what’s known that wizards and Muggles are genetic variations of the same species. In his book “Fantastic Beasts and Where to Find Them”, Newt Scamander describes both wizards and Muggles as humans.

“Werewolves spend most of their time as humans (whether wizard or Muggle).”
_{^{- Fantastic Beasts and Where to Find Them}}

Since “Fantastic Beasts and Where to Find Them” is a textbook based on science, it seems very unlikely that Newt would describe them both as humans if they were in fact different species. As Newt is a magizoologist and would understand what makes species the same or different, his statement would be based on their proper scientific classification rather than his own personal opinion on Muggles. Furthermore, lycanthropy only seems to be transmittable to wizards and Muggles (both types of human), but not to other types of creatures, so wizards and Muggles are somewhat biologically similar.

“Humans turn into werewolves only when bitten. There is no known cure, though recent developments in potion-making have to a great extent alleviated the worst symptoms. Once a month, at the full moon, the otherwise sane and normal wizard or Muggle afflicted transforms into a murderous beast. Almost uniquely among fantastic creatures, the werewolf actively seeks humans in preference to any other kind of prey.”
_{^{- Fantastic Beasts and Where to Find Them}}

In addition, there are certain types of creatures with powers that affect both wizards and Muggles, but aren’t mentioned to work on creatures other than humans.

“In some cases Muggle-Repelling Charms will not work, as the beast’s own powers will cancel them. Cases in point are the kelpie, whose sole aim in life is to attract humans towards it, and the Pogrebin, which seeks out humans for itself.”
_{^{- Fantastic Beasts and Where to Find Them}}

This implies a certain amount of biological similarity between wizards and Muggles, since they’re both uniquely susceptible to these creatures’ effects, which work seemingly only on humans (wizard or Muggle).

Answer 2

No, they are not

UPD. I actually addressed this question to clarify that. In short - it is observed that hybrids tend to become sterile in later generations even if they are born fertile. Back to liger example - ligers do exist, but only within a few generations.

Which backs up my answer below, that if Wizards and Muggles were different species, former would sooner or later die off either as a result of prolonged inbreeding or as a result of hybrid breakdown.

This states, that different species can only mate if they are really close (e.g. donkey and a horse), but the offspring will be sterile.

However, two mules cannot reproduce to produce a mule. They are sterile. ... It is possible to mate different species who are damn close, like a horse and a donkey make a mule, but that offspring is always infertile itself, so cannot make a new species.

Therefore if pure-bloods tried to mate with Muggles all of them would simply die off being unable to reproduce themselves.

Answer 3

In a strict biological sense, no

Different species can produce offspring but this offspring itself cannot reliably go on to mate. This rules out muggles and pure-bloods being separate species in the strict biological sense...however Professor Flitwick is said to have 'goblin ancestory' - unless Goblin's and humans aren't separate species then this wouldn't be possible.

What can we know?

• Magic is hereditary: We see a clear path in which wizards and witches are often born to magical parents - more often than they're born to muggle parents
• The gene appears be dominant: Hagrid's parents were a giantess and a wizard. Giants have no magic themselves so, if magic was a recessive gene, it wouldn't have been present in Hagrid
• There must be some gene (or protein) which suppresses it: Filch was a squib - two magical parents producing a non-magical child
• Witches and wizards born to muggle parents do occur but with a low chance - this must mean that magical blood and the 'suppressive gene' must both be present in most humans - it is only when a child contains only the magical gene and no suppressive one can muggle parents produce a non-muggle child

Different species though? It doesn't seem so. Much as hair colour, your ear lobes or ability to roll your tongue may set you apart from others it doesn't define you as a different species and magic appears to work in the same way.