Are mice and rats dependent on humans?

ZooBinh said:
It doesn't mean the same thing as adaptation does it? No, it doesnt. Mice and rats adapted to symbiotically live alongside humans in a commensal way, in no way are they dependent on human life. We just create ecosystems that they flourish in. They got used to us being around and lived alongside us, but they didn't "alter their genome" to live with us...
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You can look up un studies how the genome of multible rodents have changed directly to cope with human influnces. Most infamously with poison resistences.
 
For further info, the first recorded rat species was recorded 54 million years ago. The time we believe humans existed was about 5.5 million I think. Not sure it this helps, just putting it out there.
 
FBBird said:
After the island of St Kilda was evacuated, the local House Mouse population disappeared.
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Well, I said species for an reason. So even though the story of the St Kilda house mouse ( of which I was tbh not awear of) does still not disagrees with me. And over all suports my claims.
 
ZooBinh said:
Why did you say 'coevolved' in your initial post then?
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because it still follows the defination of coevolve. Evolution does not talk about "the creation of new species" It talks about the changes gene sequences in populations. While coevolution discribes evolution of direct interplay of two(in some cases more) species. Poisons and Venoms are good examples. If a poisonous species is hunted by a predetor, it devolops a higher doses/stonger poison. The predetor on the other hand is forced to develop are stronger resitence. In the short no new species is created. But both species coevolve with each other. Just like in mice and rats. The example of the St.Kilda house mouse is a good example. A subspecies of mouth, that devolped directly because of human influnce. When human left the islands, the sub species died out.
 
GiratinaIsGod said:
The example of the St.Kilda house mouse is a good example. A subspecies of mouth, that devolped directly because of human influnce. When human left the islands, the sub species died out.
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No it is not. The mice on St. Kilda did not evolve into a new subspecies, they were a population introduced by humans. St. Kilda is a tiny 3.3 square mile island in the North Atlantic Ocean. A tiny area such as that probably cannot support a large population of introduced mammals without assistance, yes, but this is one example out of literal hundreds, if not thousands of introduced populations. We could equally look at Gough Island in the South Atlantic, which is a larger island (35sqmi) that also has little to no human population remaining. Yet here we see a flourishing population of House Mice, which have been so successful that they've begun to undergo island gigantism. Their continued existence and subsequent evolution has nothing to do with humans, as the population is self-sufficient without them.

~Thylo
 
ThylacineAlive said:
No it is not. The mice on St. Kilda did not evolve into a new subspecies, they were a population introduced by humans. St. Kilda is a tiny 3.3 square mile island in the North Atlantic Ocean. A tiny area such as that probably cannot support a large population of introduced mammals without assistance, yes, but this is one example out of literal hundreds, if not thousands of introduced populations. We could equally look at Gough Island in the South Atlantic, which is a larger island (35sqmi) that also has little to no human population remaining. Yet here we see a flourishing population of House Mice, which have been so successful that they've begun to undergo island gigantism. Their continued existence and subsequent evolution has nothing to do with humans, as the population is self-sufficient without them.

~Thylo
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Self edit: It appears as though the mouse population on St. Kilda was recognized as a separate subspecies, M. m. muralis, however I highly doubt this was valid. If the taxa was introduced by human settlers rather than a natural endemic, then it's highly unlikely that it speciated enough to warrant subspecies status. It appears these animals just experienced the same island gigantism that the introduced mice on Gough Island and the Faroe Islands experienced.

Being introduced would also explain why it died out once the human settlements were abandoned, as in this case the tiny St. Kilda could not provide proper food and shelter for the, probably always small, introduced population.

~Thylo
 
ThylacineAlive said:
Self edit: It appears as though the mouse population on St. Kilda was recognized as a separate subspecies, M. m. muralis, however I highly doubt this was valid. If the taxa was introduced by human settlers rather than a natural endemic, then it's highly unlikely that it speciated enough to warrant subspecies status. It appears these animals just experienced the same island gigantism that the introduced mice on Gough Island and the Faroe Islands experienced.

Being introduced would also explain why it died out once the human settlements were abandoned, as in this case the tiny St. Kilda could not provide proper food and shelter for the, probably always small, introduced population.

~Thylo
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So I looked into the St. Kilda mice a bit more and here's what I found. Historically, two rodent species have been introduced to the island by early Viking settlers: the House Mouse and European Field Mouse. St. Kilda, being an extremely small and exposed island in the North Atlantic, experiences extremely harsh conditions. These conditions caused the introduced mice to undergo the natural selection process constantly and the survivors experienced rapid differentiation quite quickly. The differences apparently are enough to warrant separate subspecies status for these animals, despite not being natural populations. The aforementioned St. Kilda House Mouse did become dependent on human settlements for survival, and once the island was abandoned the entire population died off within two years. The St. Kilda Field Mouse, on the other hand, was able to adapt to survive in the surrounding wilderness, and only moved into the abandoned settlements once the House Mouse had mostly died off.

What we're left with is actually a very fascinating but isolated case of rapid evolution. In the case of both species, their presence on the island would not be possible without introductions from humans, but their differentiation is the result of the selective pressures the island put on them, not due to any kind of weird co-evolution with humans. Still, this specific population of House Mouse did become dependent on humans and in the end died off without their continued presence on the island. The field mouse, however, has continued to thrive in their new ecosystem despite the absence of mankind.

~Thylo
 
ThylacineAlive said:
No it is not. The mice on St. Kilda did not evolve into a new subspecies, they were a population introduced by humans. St. Kilda is a tiny 3.3 square mile island in the North Atlantic Ocean. A tiny area such as that probably cannot support a large population of introduced mammals without assistance, yes, but this is one example out of literal hundreds, if not thousands of introduced populations. We could equally look at Gough Island in the South Atlantic, which is a larger island (35sqmi) that also has little to no human population remaining. Yet here we see a flourishing population of House Mice, which have been so successful that they've begun to undergo island gigantism. Their continued existence and subsequent evolution has nothing to do with humans, as the population is self-sufficient without them.

~Thylo
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What Gough Island has, that St Kilda doesn't, is colonies of big juicy ground nesting seabirds. Any mice on St Kilda wishing to nosh on seabird chicks would have to develop extreme cliff climbing skills. It might not be entirely tied in with the size of the island. Mice don't need a huge amount of space.
 
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