Why Did Homo Erectus Not Retain a Tail?

A tail would be incredibly helpful for balance (tripod example), productivity, etc. I read that it could have been the climate change from forest to desert that could have been the reasoning.What is the best current explanation? (other than natural selection/god just did it)Edited by mram10, : No reason given.

Thread copied here from the Why Did Homo Erectus Not Retain a Tail? thread in the Proposed New Topics forum.

That covers it. The game is to pick one.Edited by Tangle, : No reason given.

Why Homo erectus? It seems a very odd choice.

Apes have no tails. You have to go back further than homo erectus to find out why.

I wonder if the loss of a tail pressured our descent from the trees or followed it.

That seems unlikely. As an extreme imagine a gibbon born without a tail (or a reduced one). This would be so detrimental that it would be strongly selected against.Having been forced from the trees for other reasons (e.g., fewer trees) would allow tails to disappear as they are redundant and even detrimental as they require support resources.

As others have pointed out apes lost their tales long before H. erectus or even the entire Homo line showed up on the scene, thus there was no tail for H. erectus to retainEdited by DrJones*, : No reason given.

As someone has already pointed out, no apes have tails, which not only makes the question of choosing any particular 'homo' species quite poor, but it also brings into question the rest of the question in the OP.Monkeys have tails, so the idea that those tails provide a useful advantage by providing balance for larger animals does not seem to be correct either. This is not a complete answer thought, because many large animals do have tails that serve non balancing functions like swatting flies.And why is natural selection eliminated as an answer. My guess is that mram10 really wants to explore what the factors are that might make not having a tail advantageous. I am rejecting more negative guesses that do not reflect well on the OP.I would suggest that tails on apes/monkeys are not a huge advantage for monkey/apes not primarily living in trees, so a deleterious mutation that resulted in those animals losing their tails after they had changed to a life style living below trees would not be only slightly deleterious. Tails do interfere with sitting down so maybe there was a slight advantage. So perhaps a combination of natural selection and drift is the explanation.At any rate a quick search on google turned up a link to this paper, whose abstract seems to propose an explanation that might just as well be in Sanskrit for me. I have no idea what they are talking about.Mutational tail loss is an evolutionary mechanism for liberating marapsins and other type I serine proteases from transmembrane anchors - PubMedABE:I see this question in another thread: "Where did natural selection get it's intelligence?", so perhaps I am giving mram too much credit. Edited by NoNukes, : No reason given.

Yup, I see what you mean.And half my major in grad school was in physical anthropology.Lots of things changed since those days.

That's like asking for the current best answer to 1 + 1 (other than 2).The current best explanation is natural selection. Indeed it would. I've often thought that two little arms coming out of my temples would be incredibly helpful because they could hold things where I could see them.But evolution doesn't work that way. Changes happen randomly and the environment selects the ones that work best.

Clearly the only explanation is that when God designed us he screwed up like the great celestial doofus that he is. Next time you're praying, perhaps you could explain to him (tactfully) how stupid he is and ask him to bestow upon you the glorious gift of a tail.Personally I find I manage to balance just fine without one, but maybe you're always falling over backwards and hitting your head on things. I don't know why you think having a tail would increase your "productivity", nor do I think --- having seen what you produce --- that that would necessarily be a good idea.

Having four legs and a tail would be more advantageous for balance than just having a tail (calfs for example; they can stand up on all fours an hour after birth, but their productivity in building a shelter is quite dismal). Actually, the ideal would be for humans to have four legs and a tail (for balance) and two arms with hands, fingers and opposable thumbs at the end of the arms (for productivity). From the evidence it seems as if the great apes never had all those legs to improve balance. What a pity. It seems as if the great apes were badly designed. We have empirical evidence for the existence of natural selection. The evidence is also verifiable.We still have none for the existence of a supernatural designer. Not empirical, neither verifiable.Edited by Pressie, : No reason given.

I found this information which was posted by Alicia Rich, who is a Biological Anthropologist and Primatologist, as it relates to why apes don't have tails and what might have been the driving factor in that change:

quote:

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First of all, great apes did not evolve on the African savannas and grasslands. Some people have argued that early hominins did, but that is a complicated debate in itself. In fact, there are only two neighboring communities of chimpanzees that are commonly referred to as "savanna chimpanzees," and just a couple more populations that we refer to as "dry habitat chimpanzees" (including the community that I study). When apes evolved during the Miocene, they likely split from their common ancestor with monkeys because of a change in ecological niche. Things were only slightly drier and more open in Africa than before (nothing like the dry, open place that it is today), so primates were still living in heavily forested habitats feeding in the trees. Today, most great apes still live in highly forested parts of Africa, and a few live in the drier "woodland" type habitats.

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As their environment changed, and populations grew, there was probably a change in feeding ecology that pressured apes and monkeys to develop different traits to reduce competition. Monkeys today are able to feed on unripe fruit because of a different digestion system than ours. Apes are what we call "ripe-fruit specialists" (that includes us). Our digestive system cannot absorb enough nutrients to compensate for the digestive power needed for processing the unripe fruits. So as monkeys needed a physiology for moving around on the upper levels and inner portions of the trees where unripe fruits were abundant, miocene apes specializing on ripe fruits probably needed a different physiology for moving around on the peripheral branches and occasionally to the ground to collect the ripe fruits that reached maturity.

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Once you picture a scenario like that, you should ask the question of why an individual might need a tail. For balance? Perhaps. Many monkeys with long tails are quadrupedal branch runners and walkers. Apes that do move in the trees a lot, tend to move below the branches instead of above. They hang by their arms to collect the ripe fruits on the peripheral branches, dropping down to the ground if the need arises. If the tail was no longer helping individuals to balance above branches, but instead was only there as another appendage to injure or waste energy developing, individuals with shorter and smaller tails would have been more efficient feeders, and better at surviving.

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I'm no expert in this regard, but for those on the forum that are familiar with these fields of study, does the above explanation make sense?

I think having no legs would be best, balance-wise. I've never seen nor heard of a worm or snake falling over and breaking a hip.