Stop using "race" and "species" interchangeably. Race is a subset of species (like breed, or subspecies).
If they can breed with humans, then they're biologically human themselves (this goes for Neanderthals, Denisovans, or any other extinct races of human who could breed with humans living today.)
The only way some species from another planet, that is, a completely different natural petri dish of evolution would be able to "breed" with humans is if they had some massive genetic engineering chops under their belts (which is likely, if they can cross interstellar space) - but shit, that would be like humans wanting to splice their genes with horses or bears, and shit, they'd complain if you tried to see if chimpanzee zygotes can cross in a fucking test tube.
Even shit-ass Star Trek sorted this out with Spock's World (a novel), which specifically detailed that making Spock was NOT a natural - or cheap - endeavour. He was made in a test tube. The problem with the last season of Enterprise is, it shouldn't have been humans bitching about crossing with Vulcans, it should have been Vulcans disgusted at being mixed with hairless chimps!
Liger: The liger is a hybrid offspring of a male lion (Panthera leo) and a female tiger (Panthera tigris)
Liger: Species: P. leo♂ × P. tigris♀
See the problem with all discussions regarding, race, species, subspecies, etc... is that everyone uses the words wrong. Humans do in fact consist of different species. There's about 3-4 distinct species. Then tons of hybrids and many subspecies. I am suggesting that there does exist an alien race that is a different species but the same Family or Genus such that they can mate with humans but are so distinctly different, no one can deny they are a different species, unlike how everyone today denies the existence of different species of humans.
Taxonomy is a mess, and was invented in the first place by a CREATIONIST, not someone thinking along evolutionary lines. If two creatures can make babies that are fully viable and interfertile, then they're the same species.
Keeping in mind that speciation is a process and not an event, of course you're going to find animal groups along a SPECTRUM of how well they can breed with each other, but the cut-off should be set fucking hard at "viable but not fertile" (ie, mules, or that European arthropod group that spawned a parthenogenic new species about 25-30 years ago).
Race? Well, if you can tell the difference between one group and another, and those groups tend to prefer themselves to breed and associate with, you probably have two races. It's more than skin deep, and a race is just a stepping stone on the way to speciation. The first thing to split a species is probably communication and behaviour, with looks (ie, skin or coat colour) just being a visual marker (and there may be scent markers as well.) Races themselves would start out as "evolutionary variants within a population" that simply became common enough to become self-perpetuating (ie, they can find and mate with each other and don't have to settle for breeding with the majority.)
The reason sci-fi has human-alien hybrids is because of the CREATIONIST myth that if something looks the same, then they must be the same (even though Linne erroneously made dogs, wolves and coyotes different species, which they are most certainly not, and the only difference between them is looks and lifestyle - same as humans. But that twit was so afraid of recognizing human closeness with other apes, he deliberately gave them each their own genus because of religious reasons and his own personal sense of taste. Add to that the conceit that anything "smart" has to look like a human, well. It's garbage, and should be classed as "space fantasy" rather than "sci fi".
I mean, seriously, using Linne's own logic and rules, imagine we're "starfish" aliens from some distant planet, studying the creatures of Earth. We take a human from England, and a human from Japan (and let's say the year is roughly 1000 AD, or earlier.) We know that the way they make their hives looks a little bit different, and they come from islands on opposite sides of the planet. They even look a bit different, and like different foods. Are they different species? Let's put them in a cage and find out. Oh, look, the female rejected the male. Oops, the male killed her. Different species! Yep, that's the logic he used to put wolves and coyotes as different species. Even though they can make babies. But dingbats like him don't think that "animals" can be "racist". At the very least, genetics studies are starting to force them to realize where they went stupid. Oh, and there's only one species of rabbit, and one species of hare, but they both have many races. And apparently, North America only has one species of bear.
Let's just cut to the whole point. You're saying Tigers and Lions are the same species. Cool. Every single person on the planet considers them two distinct animals. Same species or not. No one thinks of Tigers and Lions as being the same. They hunt differently, the look completely different, they live in different areas. Everyone just understands they're a type of big cat but they are a distinct animal.
All I'm trying to get at is that humans are the same. A negro, an asian and an aryan are distinct animals. We are not the same. We are as different as a lion and a tiger more-or-less. However, that is not what most people think. Most people think if it weren't for Male Lion Supremacy oppressing the Tiger, that the two animals would be identical in every regard except the color of its fur. This is simply not true.
All I'm suggesting is maybe we encounter an alien as different as a Lion is from a Tiger but another humanoid as different from humans on Earth that no one could deny they were distinctly a different "animal" like how no one disputes that a Lion or Tiger is different.
Humans are NOT all the same. A white guy with expensive equipment DOES hunt differently from a fucking Sentinelese. Anyone thinking some numbnuts modern Inuit with his high powered rifle, Goretex tent, and Fucking Snowmobile is doing anything at all fucking "traditional" is a goddamned retard.
Sigh. I'm arguing that BEHAVIOUR is a horrible way to define species, and only a retarded fucking creationist would even think of doing it that way.
Stop using "race" and "species" interchangeably. Race is a subset of species (like breed, or subspecies).
If they can breed with humans, then they're biologically human themselves (this goes for Neanderthals, Denisovans, or any other extinct races of human who could breed with humans living today.)
The only way some species from another planet, that is, a completely different natural petri dish of evolution would be able to "breed" with humans is if they had some massive genetic engineering chops under their belts (which is likely, if they can cross interstellar space) - but shit, that would be like humans wanting to splice their genes with horses or bears, and shit, they'd complain if you tried to see if chimpanzee zygotes can cross in a fucking test tube.
Even shit-ass Star Trek sorted this out with Spock's World (a novel), which specifically detailed that making Spock was NOT a natural - or cheap - endeavour. He was made in a test tube. The problem with the last season of Enterprise is, it shouldn't have been humans bitching about crossing with Vulcans, it should have been Vulcans disgusted at being mixed with hairless chimps!
Tiger: Species: P. tigris
Lion: Species: P. leo
Liger: The liger is a hybrid offspring of a male lion (Panthera leo) and a female tiger (Panthera tigris)
Liger: Species: P. leo♂ × P. tigris♀
See the problem with all discussions regarding, race, species, subspecies, etc... is that everyone uses the words wrong. Humans do in fact consist of different species. There's about 3-4 distinct species. Then tons of hybrids and many subspecies. I am suggesting that there does exist an alien race that is a different species but the same Family or Genus such that they can mate with humans but are so distinctly different, no one can deny they are a different species, unlike how everyone today denies the existence of different species of humans.
Taxonomy is a mess, and was invented in the first place by a CREATIONIST, not someone thinking along evolutionary lines. If two creatures can make babies that are fully viable and interfertile, then they're the same species.
Keeping in mind that speciation is a process and not an event, of course you're going to find animal groups along a SPECTRUM of how well they can breed with each other, but the cut-off should be set fucking hard at "viable but not fertile" (ie, mules, or that European arthropod group that spawned a parthenogenic new species about 25-30 years ago).
Race? Well, if you can tell the difference between one group and another, and those groups tend to prefer themselves to breed and associate with, you probably have two races. It's more than skin deep, and a race is just a stepping stone on the way to speciation. The first thing to split a species is probably communication and behaviour, with looks (ie, skin or coat colour) just being a visual marker (and there may be scent markers as well.) Races themselves would start out as "evolutionary variants within a population" that simply became common enough to become self-perpetuating (ie, they can find and mate with each other and don't have to settle for breeding with the majority.)
The reason sci-fi has human-alien hybrids is because of the CREATIONIST myth that if something looks the same, then they must be the same (even though Linne erroneously made dogs, wolves and coyotes different species, which they are most certainly not, and the only difference between them is looks and lifestyle - same as humans. But that twit was so afraid of recognizing human closeness with other apes, he deliberately gave them each their own genus because of religious reasons and his own personal sense of taste. Add to that the conceit that anything "smart" has to look like a human, well. It's garbage, and should be classed as "space fantasy" rather than "sci fi".
I mean, seriously, using Linne's own logic and rules, imagine we're "starfish" aliens from some distant planet, studying the creatures of Earth. We take a human from England, and a human from Japan (and let's say the year is roughly 1000 AD, or earlier.) We know that the way they make their hives looks a little bit different, and they come from islands on opposite sides of the planet. They even look a bit different, and like different foods. Are they different species? Let's put them in a cage and find out. Oh, look, the female rejected the male. Oops, the male killed her. Different species! Yep, that's the logic he used to put wolves and coyotes as different species. Even though they can make babies. But dingbats like him don't think that "animals" can be "racist". At the very least, genetics studies are starting to force them to realize where they went stupid. Oh, and there's only one species of rabbit, and one species of hare, but they both have many races. And apparently, North America only has one species of bear.
Let's just cut to the whole point. You're saying Tigers and Lions are the same species. Cool. Every single person on the planet considers them two distinct animals. Same species or not. No one thinks of Tigers and Lions as being the same. They hunt differently, the look completely different, they live in different areas. Everyone just understands they're a type of big cat but they are a distinct animal.
All I'm trying to get at is that humans are the same. A negro, an asian and an aryan are distinct animals. We are not the same. We are as different as a lion and a tiger more-or-less. However, that is not what most people think. Most people think if it weren't for Male Lion Supremacy oppressing the Tiger, that the two animals would be identical in every regard except the color of its fur. This is simply not true.
All I'm suggesting is maybe we encounter an alien as different as a Lion is from a Tiger but another humanoid as different from humans on Earth that no one could deny they were distinctly a different "animal" like how no one disputes that a Lion or Tiger is different.
Humans are NOT all the same. A white guy with expensive equipment DOES hunt differently from a fucking Sentinelese. Anyone thinking some numbnuts modern Inuit with his high powered rifle, Goretex tent, and Fucking Snowmobile is doing anything at all fucking "traditional" is a goddamned retard.
Sigh. I'm arguing that BEHAVIOUR is a horrible way to define species, and only a retarded fucking creationist would even think of doing it that way.