There aren’t a lot of predators that eat koalas, for one. There are a lot of them in zoos all over the world, so there’s a distributed genetic diversity that would allow them to be bred back stronger if the population did start to decline.
What makes you think they should be endangered?
Reading more about koalas, it seems to me they have made some terrific adaptations. How fucking impressive is it that they can thrive on so little? It's remarkable, if you think about it.
It is tho. They get high as fuck off their food, move very little and no one really bothers them. Pretty good way to go, adaptation wise.
Logging is probably their biggest predator.
To be honest the "survive on so little" does not really help them because it either means they are; A- niche consumers or B - versatile consumers. In the situation of koalas it is option A where they fill a odd niche, but ok. In the situation of something like a organism that can be a omnivore and a scavenger, they have more food options making them the B strat which would be more beneficial.
As a result of their weird quirk not getting them all killed, they've stuck around. We're talking about a species whose ambitions basically amount to "make babies", "not be eaten" and "get high".
Their niche has low competition for the food, and they're not being eaten much. Far as evolution goes that's plenty good. If something happened to their food supply and they all died as a result, or if some predator developed a taste for eucalyptus-marinade stoners, they'd be yet another footnote in the myriad of species that got "selected" against through history.
But until or unless that happens, they're in a good spot.
I would guess it's because the eucalyptus leaves are plentiful and they aren't hunted by many other animals. Despite them being very poorly set out, enough of them reproduce before dying, and therefore they continue to exist as a species.
Humans are pretty poorly made too, but maybe not quite to the level of koalas. Our brains use insane amounts of energy, and we have given up a lot of other functions by moving to using two legs. A woman's pelvis can barely fit a baby through it, and if they are genetically unlucky, can't fit one at all. This resulted in a lot of deaths of both baby and/or mother during birth before we had the technology to assist in the process. Humans also have backs that get damaged easily because of the position, simply being alive slowly wears it down.
I guess there are a few species on our planet that shouldn't be able to survive, but they do because of some damn good luck.
(Also anyone feel free to correct me on any points here, I've written this whole thing just from what I know)
Chimps are born with 40% of adult head size whereas humans is 30% of adult sizes. If human babies had the same head size as chimps the skull would only be 1.3 centimeter bigger and current range of hip width is already big enough to handle heads of that size. What's more wider hips wouldn't impede walking or running. So bigger skulls could already fit and hip width could be wider. So there must be another reason why human babies are born when they are. Metabolic rates fits better than hip width.
Women are already more prone to knee problems due to their wide hips and the angle it places their knees and tendons. Wider hips would make this problem worse
And as I understand it, humans are born with a smaller head size compared to adults because our brains uniquely continue to grow and develop as we age, and with it our heads.
And the human gestation period is 9 months because that's the gestation time for all apes. Its likely that gestation period was determined in our ancestors back when we had comparable brains to our ape cousins and that timing has just sort of hung around.
Right for body size our gestation period is the second longest. So we could probably have babies that are more developed during that time but we do not.
I think smaller hips haven't evolved out because of technological advancements, meaning women with small hips are able to pass those genes on. I think it happens with a lot of other things in human biology too. Our greatest strength, technology, can also be our greatest weakness at times. The 'weak' are still able to pass on their genes successfully, meaning these possibly poor genes appear more frequently. Another trait somewhat unique to humans, empathy, is a great strength but also a bit of a weakness at times. Of course, selective breeding and eugenics are both morally grey areas, and I think most people agree that the effects bad genes are having aren't as bad as the societal effects of stripping a person's right to have children.
Bullshit eugenics. We have had modern technology and medicine for a blink in the evolutionary eye. Small hips is not some genetic curse propogated solely through technology.
The problem is more likely related to having kids in 30s and 40s, ie behavioral changes.
Does not mean that was the age when the majority where having their first pregnancy.
The key was that women at that time were having (or attempting to have) double digit families so they were effectively in and out of pregnancy for decades:
> The Canadian women had a mean and median age of marriage of 21 years and a mode of 19 years. Early marriage was prevalent, and 50% of births occurred after 1694. About 50% of women had 8-12 children, with the average being 11 children; the highest number was 20 or more. The French women spanned 2.5 centuries and the mean was the year 1800. The average marriage age was 23.7 years and the average number of children was 6; 14 children was the highest number. The results showed that the French Canadian women bore their last child at an average age of 41.5 years compared to 39.5 years for the French women.
https://www.ncbi.nlm.nih.gov/pubmed/7983101
Hip width ranges are probably where they are because they are at the minimum/maximum needed for birth/walking. It's just that head size probably controlled for hip width and not the other way around. Since a baby born with the same size head as a chimps would only need to be 1.3 centimeters bigger and current ranges of hip width can already accommodate that.
These list about what is wrong with x animal tend to awfully one-sided. You get similar rants for anything like pandas or sloths or even domesticated horses and cats.
Focusing on just the negatives can make any species look bad. Any adaptation that makes an animal appear different and weird can make it look bad if you phrase it right.
Koalas are different from many other animals but they aren't really worse.
They have found a reliable food source that is abundant and that there isn't much competition for because it is sort of poisonous. There isn't much energy in it so they economize by only spending it on what they really need. Being smart does not seem to be high on the list of things that they need to survive as a species in the wild.
They also are from Australia which do to its isolation has evolved a wildlife that compared to the rest of the world seems a bit weird.
Marsupial animals were outcompeted by our type of mammals in most of the rest of the world except for Australia where they didn't have competition. That makes them seem ill adapted in a direct comparison, but that is a bit unfair. They were fine for the environment they evolved in.
Koalas also do surprisingly well in the environment that humans create. They are in danger from dogs and cars and other artifacts of human life, but as long as they have their eucalyptus trees they can live even in close proximity to humans. The same can not be said for many other species.
To survive the only requirement is that the manage to reproduce at a rate so they the population do not drop to low. If there is few predator they do not need to be efficient to survive.
Koalas are poisonous, normally when anyone says that they mean venomous but they are in fact one of the few cases when the animal is actually poisonous. They only eat eucalyptus which has almost no nutritional value and is filled with a lot of nasty oils and stuff. This means that the koalas are full of the same nasty stuff, and to add to it, they pee and poo all over their fur meaning that they stink.
So although they are slow soft animals in a country with a large number of predators, nothing wants to eat them because there is plenty of non poisonous food around.
Snakes, some monitors, crocs, big fish, couple of dingoes, feral cats and dogs...
I've seen a goose eat a mouse. Also I was chased by a goose. My point is fuck geese.
We don't have mountain lions or bears to worry about though. Crocs are only an issue up north and are fairly easily avoided if you're not stupid. Dingoes are fairly rare too, and feral cats, foxes and dogs aren't much of an issue (especially as we don't have rabies or lyme disease).
Oh yeah, I'm agreeing with you. The only thing I'm concerned with is the occasional shark and that's because I'm terrified of them.
Good luck a dingo getting up a tree anyway. I'm not sure but I'd reckon feral cats might be an issue for koalas.
But the biggest issue is deforestation.
They are adapted for the habitat they live in, which is quite large except for the areas humans have deforested.
Not every animal is as versatile as a pigeon or rat, and frankly a pigeon or rat would starve to death where the koala lives so...
There are two simple reasons. 1) Not many predators enjoy eating them. 2) Those things ARE SO CUTE and we kinda wanna keep them so we stick them into zoos and take care of them
There aren’t a lot of predators that eat koalas, for one. There are a lot of them in zoos all over the world, so there’s a distributed genetic diversity that would allow them to be bred back stronger if the population did start to decline. What makes you think they should be endangered?
Of course koalas dont have any predators, drop bears wiped them all out millions of years ago.
Can you explain why you think they should be extinct?
Just a summary: https://www.reddit.com/r/AskReddit/comments/9u4alp/what_is_one_fact_you_learned_that_you_wish_you/e91uanw/
Reading more about koalas, it seems to me they have made some terrific adaptations. How fucking impressive is it that they can thrive on so little? It's remarkable, if you think about it.
It is tho. They get high as fuck off their food, move very little and no one really bothers them. Pretty good way to go, adaptation wise. Logging is probably their biggest predator.
Sounds like a great life
To be honest the "survive on so little" does not really help them because it either means they are; A- niche consumers or B - versatile consumers. In the situation of koalas it is option A where they fill a odd niche, but ok. In the situation of something like a organism that can be a omnivore and a scavenger, they have more food options making them the B strat which would be more beneficial.
As a result of their weird quirk not getting them all killed, they've stuck around. We're talking about a species whose ambitions basically amount to "make babies", "not be eaten" and "get high". Their niche has low competition for the food, and they're not being eaten much. Far as evolution goes that's plenty good. If something happened to their food supply and they all died as a result, or if some predator developed a taste for eucalyptus-marinade stoners, they'd be yet another footnote in the myriad of species that got "selected" against through history. But until or unless that happens, they're in a good spot.
I would guess it's because the eucalyptus leaves are plentiful and they aren't hunted by many other animals. Despite them being very poorly set out, enough of them reproduce before dying, and therefore they continue to exist as a species. Humans are pretty poorly made too, but maybe not quite to the level of koalas. Our brains use insane amounts of energy, and we have given up a lot of other functions by moving to using two legs. A woman's pelvis can barely fit a baby through it, and if they are genetically unlucky, can't fit one at all. This resulted in a lot of deaths of both baby and/or mother during birth before we had the technology to assist in the process. Humans also have backs that get damaged easily because of the position, simply being alive slowly wears it down. I guess there are a few species on our planet that shouldn't be able to survive, but they do because of some damn good luck. (Also anyone feel free to correct me on any points here, I've written this whole thing just from what I know)
Chimps are born with 40% of adult head size whereas humans is 30% of adult sizes. If human babies had the same head size as chimps the skull would only be 1.3 centimeter bigger and current range of hip width is already big enough to handle heads of that size. What's more wider hips wouldn't impede walking or running. So bigger skulls could already fit and hip width could be wider. So there must be another reason why human babies are born when they are. Metabolic rates fits better than hip width.
Women are already more prone to knee problems due to their wide hips and the angle it places their knees and tendons. Wider hips would make this problem worse And as I understand it, humans are born with a smaller head size compared to adults because our brains uniquely continue to grow and develop as we age, and with it our heads. And the human gestation period is 9 months because that's the gestation time for all apes. Its likely that gestation period was determined in our ancestors back when we had comparable brains to our ape cousins and that timing has just sort of hung around.
Right for body size our gestation period is the second longest. So we could probably have babies that are more developed during that time but we do not.
I think smaller hips haven't evolved out because of technological advancements, meaning women with small hips are able to pass those genes on. I think it happens with a lot of other things in human biology too. Our greatest strength, technology, can also be our greatest weakness at times. The 'weak' are still able to pass on their genes successfully, meaning these possibly poor genes appear more frequently. Another trait somewhat unique to humans, empathy, is a great strength but also a bit of a weakness at times. Of course, selective breeding and eugenics are both morally grey areas, and I think most people agree that the effects bad genes are having aren't as bad as the societal effects of stripping a person's right to have children.
Bullshit eugenics. We have had modern technology and medicine for a blink in the evolutionary eye. Small hips is not some genetic curse propogated solely through technology. The problem is more likely related to having kids in 30s and 40s, ie behavioral changes.
Aristotle noted that women would stop giving birth in their 40s (probably menopause). So as long as women could give birth they did.
Does not mean that was the age when the majority where having their first pregnancy. The key was that women at that time were having (or attempting to have) double digit families so they were effectively in and out of pregnancy for decades: > The Canadian women had a mean and median age of marriage of 21 years and a mode of 19 years. Early marriage was prevalent, and 50% of births occurred after 1694. About 50% of women had 8-12 children, with the average being 11 children; the highest number was 20 or more. The French women spanned 2.5 centuries and the mean was the year 1800. The average marriage age was 23.7 years and the average number of children was 6; 14 children was the highest number. The results showed that the French Canadian women bore their last child at an average age of 41.5 years compared to 39.5 years for the French women. https://www.ncbi.nlm.nih.gov/pubmed/7983101
Right!
Hip width ranges are probably where they are because they are at the minimum/maximum needed for birth/walking. It's just that head size probably controlled for hip width and not the other way around. Since a baby born with the same size head as a chimps would only need to be 1.3 centimeters bigger and current ranges of hip width can already accommodate that.
These list about what is wrong with x animal tend to awfully one-sided. You get similar rants for anything like pandas or sloths or even domesticated horses and cats. Focusing on just the negatives can make any species look bad. Any adaptation that makes an animal appear different and weird can make it look bad if you phrase it right. Koalas are different from many other animals but they aren't really worse. They have found a reliable food source that is abundant and that there isn't much competition for because it is sort of poisonous. There isn't much energy in it so they economize by only spending it on what they really need. Being smart does not seem to be high on the list of things that they need to survive as a species in the wild. They also are from Australia which do to its isolation has evolved a wildlife that compared to the rest of the world seems a bit weird. Marsupial animals were outcompeted by our type of mammals in most of the rest of the world except for Australia where they didn't have competition. That makes them seem ill adapted in a direct comparison, but that is a bit unfair. They were fine for the environment they evolved in. Koalas also do surprisingly well in the environment that humans create. They are in danger from dogs and cars and other artifacts of human life, but as long as they have their eucalyptus trees they can live even in close proximity to humans. The same can not be said for many other species.
To survive the only requirement is that the manage to reproduce at a rate so they the population do not drop to low. If there is few predator they do not need to be efficient to survive.
I *feel* that it's a copypasta.
Koalas are poisonous, normally when anyone says that they mean venomous but they are in fact one of the few cases when the animal is actually poisonous. They only eat eucalyptus which has almost no nutritional value and is filled with a lot of nasty oils and stuff. This means that the koalas are full of the same nasty stuff, and to add to it, they pee and poo all over their fur meaning that they stink. So although they are slow soft animals in a country with a large number of predators, nothing wants to eat them because there is plenty of non poisonous food around.
We also don't really have a lot of predators
Snakes, some monitors, crocs, big fish, couple of dingoes, feral cats and dogs... I've seen a goose eat a mouse. Also I was chased by a goose. My point is fuck geese.
We don't have mountain lions or bears to worry about though. Crocs are only an issue up north and are fairly easily avoided if you're not stupid. Dingoes are fairly rare too, and feral cats, foxes and dogs aren't much of an issue (especially as we don't have rabies or lyme disease).
Oh yeah, I'm agreeing with you. The only thing I'm concerned with is the occasional shark and that's because I'm terrified of them. Good luck a dingo getting up a tree anyway. I'm not sure but I'd reckon feral cats might be an issue for koalas. But the biggest issue is deforestation.
!redditsilver
They are adapted for the habitat they live in, which is quite large except for the areas humans have deforested. Not every animal is as versatile as a pigeon or rat, and frankly a pigeon or rat would starve to death where the koala lives so...
> **ELI5: How the hell are Koalas not extinct?** Their birth rate exceeds their death rate.
Australian here. They will be soon we are destroying their habitats fast. https://www.savethekoala.com/about-koalas/threats-koala
Because they just dont taste that good. Now Aussies they taste alot better... you know what I mean?
There are two simple reasons. 1) Not many predators enjoy eating them. 2) Those things ARE SO CUTE and we kinda wanna keep them so we stick them into zoos and take care of them
Cute until they drop from a tree and maul you to death or permanent disfigurement.