Questions about animals in the Americas:
Did the deer, squirrels, ants, wolves, etc. all evolve into different species?
Why didn’t the livestock animals like cattle, sheep, or chickens come along with the continental split?
Are dogs native, or did they come with the Europeans? Can we really distinguish them from the wolves anyway?
Are rats native?
Are housecats native?
I know you aren’t going to like this but your questions are broad the way they are written and contain some ambiguous terms like continental splitting. I assume you are talking about North America separating from some other continents but the time scale of that is massive and affects all your other questions. You are talking about tens of millions of years of geological history combined with human migration patterns at once and that won’t lead to many meaningful answers without clarification. It is also misleading. Asia and Europe are obviously connected by land but technically so is Africa and you can almost connect both North and South America to each other and to Asia except for the fairly narrow Bering Strait. It was fairly recently during the last Ice Age when all of them were land connected but there were climate barriers to species movement among them.
It doesn’t answer all your questions perfectly because the timescale is too big but Jared Diamond’s book ‘Guns, Germs, and Steel’ gives an excellent analysis of the way native animals affected human development and how certain species like wolves (dogs too), rats, and cats migrated with human populations.
As an aside, you will also find through different fields that the concept of a species isn’t nearly as precise as it is taught in high school. It is mainly a human construct and not something with a precise definition. The major definition is populations of animals that tend to interbreed freely in nature and produce fertile offspring but that line has many qualifications and exceptions. That point affects how different you expect different animal populations to be in different geographic locations before they are considered truly different biologically and not just through circumstance.
Deer and squirrels are different species in North America and Eurasia, but wolves are the same species. Not sure if any ant species are shared across continents; there are thousands of species of ant in the world.
Because the breakup of the continents occurred long before the domestication of livestock.
There’s archaeological evidence now that Americans had domesticated dogs thousands of years before the arrival of Europeans, but I’m not sure if that makes them a native animal.
No and no.
The Americas separated from the other continents about 100 million years ago. Dinosaurs were still dominant, and mammals of the time were no larger than rodents. Modern birds had yet to evolve at all. (I think.)
Certainly cattle, sheep, and chickens didn’t exist yet.
(On preview, heathen earthling got this, but I’ll leave the post in for the pretty map.)
From what I understand, the genus Canis originated in the Americas, then spread to the Old World across the Bering Isthmus during one of the early ice ages, then got domesticated by humans, and then came back (both the domesticated and undomesticated ones) during a later ice age. Coyotes are descended from the ones that stayed here, while wolves and domesticated dogs are descended from the ones that left and came back. In any event, dogs were already domesticated before the first humans came to the Americas, and came with them.
And modern taxonomy considers domesticated dogs to be a subspecies of wolves, not a separate species. In fact, this is the case for all domesticated animals: Housecats are considered a subspecies of the African wildcat, cows are a subspecies of aurochs, and so on.
The split between the continents (except for the isthmuses at Beringia and Panama) took place before the evolution of modern mammals. Most of North America’s native mammalian wildlife evolved either here (Nearctic fauna) or in Eurasia (Palearctic fauna) – and there were migrations across Beringia that resulted in a large group of species common to both faunal regions (the Holarctic fauna). Some groups are counterintuitive – horses and camels, for example, evolved in North America but died out here, surviving in Eurasia and being brought back by the Europeans.
That said, let’s tackleyour questions.
1. Did the deer, squirrels, ants, wolves, etc. all evolve into different species?
2. Why didn’t the livestock animals like cattle, sheep, or chickens come along with the continental split?
When the ancestors of the Native Americans entered the New World, they did not have domestic animals. (See note below.) Bison occur in both faunal regions; bighorn sheep were the North American anslogs of Old World sheep. There were galliform birds (turkey, prairie chicken) in North America. None of them were domesticated.
3. Are dogs native, or did they come with the Europeans? Can we really distinguish them from the wolves anyway?
Dogs were domesticated in the Old World, one of the earliest domestic animals. I checked with my resident paleoanthropologist, and she thinks the first Americans brought dogs with them but is unsure.
4. Are rats native?
Yes, different species. Rattus rattus came with the Europeans, AFAIK.
5. Are housecats native? No. Domesticated in the Old World, came in with Europeans.
What exactly do you mean? Many Eurasian and American animals are the same species. Reindeer and elk are the same species on both continents for example, as are wolves, brown bears and so forth. Some other animal types are different species and with so,me, such as bison, there is uncertainty about whether they are the same species. It all depends on how isolated they were, how long ago they became isolated, what selective pressures were working on them and so forth.
Once again, unclear question. As already noted, there were no domestic animals when the continents split. The Americas certainly have or had species within the same genera as many domestic animals: sheep, camels, horses, reindeer etc. but they are the result of animals walking between the continents, not the result of animals “coming along with the continental split”.
Dogs are a domestic strain, by definition they are not native to anywhere.
There are hundreds of different species of rats. Some of them are native to the Americas, most are not.
No.
:dubious:
Turkeys were domesticated. 
None of the native American “rats” are species of Rattus, though- they’re more closely related to voles.
My apologies; I had forgotten that pre-Columbian domestication of the turkey and the Muscovy duck had occurred.
Something to consider is that llamas, vicuna and alpacas are related to camels. South America shares several plants and animals related to African species. It is estimated that llamas have been domesticated for about 4000 years. Cuy (or caavies) were also domesticated and bred as a food source.
Horses were native to North America but died out long before they were re-introduced by the Spaniards.
Not sure what your point is here. Camels originated in the Americas and a single species migrated into Asia. Whether it then split into two species is debatable, but camels were taken from Asia to North Africa by people. They aren’t native to Africa. Moreover llamas and alpacas are fairly distantly related to camels (though capable of occasional hybrids), whereas North America was home to actual Camelus camels until humans arrived.
South America does have many plants and animals related to African species, and it has many more related to Australian species. That’s because these continents were all once part of the supercontinent of Gondwana. It has nothing to do with the spread of camels to Africa by human just a few thousand years ago.
Not long before. Just a few thousand years at most.
Depends on what you mean by “long before.” Horse extinction in North America is generally thought to have occurred about 11,000 years or more before the arrival of the Spanish, although possibly as late as “only” 7,000 years earlier.
In the context of a thread discussing the continental splits between the Americas and Eurasia and Gondwana, the migration of camels from the Americas to Africa and the separation between New and Old world camels, 7, 000 years is just the blink of an eye.
Heck, 7, 000 years is almost within historical times.
I was unaware that the species distinction between Bactrian and dromedary was under debate.
Given that it’s probable the dromedary was domesticated first, and that wild Bactrians still occur, it seems likely that there was a species split, and then two domestication events.
Sorry, I should question my sources better I guess. <hangs head> I had been told that the guanaco was actually the closest relative to the ancient camel. (Perhaps he meant the closest South American relative.) My source went to school in Peru. I should know their schoolbooks are as inaccurate as everyone else’s…
This is true. The camel family Camelidae originated in North America. Some true camels (genus Camelus) migrated to Asia, where they were eventually domesticated. Other members of the family migrated to South America after the formation of the Panamanian land bridge about 3 million years ago, where they gave rise to the wild guanaco and vicuna. Later the guanaco was domesticated and gave rise to the llama and alpaca.
Interesting thread. So it was just by the luck of the draw that Europeans had horses, cattle, wolves, and sheep that could be easily domesticated, but the indigenous people of North America were unlucky and had buffalo, bison, llamas, longhorn sheep, etc. that were either very difficult to domesticate or that didn’t work out as a beast of burden?
Perhaps the whole dynamic of the world would have shifted had the “good” animals been in North America.
One of the “armchair theories” I’ve read — though it might have good supporting evidence for all I know — is that pre-Columbian Americans didn’t bother with the invention of the wheel, precisely because there were no good beasts-of-burden to use them with. They did have small wheels, used in toys and religious implements, but that’s it.
So no wheels, and no carts or wagons. Therefore no point in building roads. Therefore smaller empires, and slower communication between the various towns in those empires. Therefore slower population growth and technological development.
But that’s probably oversimplifying history, just a tad.
Jared Diamond writes on that, among other things, in Guns, Germs, and Steel, a very popular book among Dopers.