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Discussion on hypothesized ancestral human cyclical ARC dive-foraging

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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trux said:
I do not really believe that photic sneeze has anything to do with diving. These are my reasons:
  1. I saw no supporting evidence showing it could
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  1. What evidence would convince you? Remember, I'm talking about the situation 100,000+ years ago to 4 million years ago, average 1 million years ago. Today's humans are different (compare skull shape, Java Man had a flat keeled skull, Neandertals had flat skull with occipital bun like an aerodynamic bike helmet, today all humans have "bubble" skulls).

    [*]It brings no advantage
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    More dive time = more food

    [*]You do not want to get rid of CO2 too fast after surfacing
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    Are you saying that exhaling CO2 quickly and replenishing lungs with air is harmful? Perhaps you mean hyperventilating upon surfacing?

    [*]It increases risk of blackout / samba
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    assumption? How could oxygenation cause a blackout or samba? Aren't they caused by lack of oxygen?

    [*]It increases risk of choking (as Laminar correctly pointed out)
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    It actually minimises that risk, I'd think, since the time exhaling/inhaling is far shorter than slowly exhaling/inhaling.
    [*]The diver might drop his prey when sneezing
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    Possible, but doubtful, we have good grips, and the hands are not involved in sneezing. Otherwise sneezing car drivers would be banned.
    [*]A sneeze underwater would likely kill the diver if he looked upwards into the light during surfacing
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    No, the under-nose baro-sensors prevent underwater sneezing, the water pressure on the nose is the same as putting finger beneath nose to stop tickle/sneeze, and actually may be the origin of this trait, since no apes do it.
    Only upon surfacing, when there is no more pressure, would the sneeze occur.
    Have you ever sneezed underwater? Nope, due to water pressure. (Though maybe guys wearing air-filled helmets might? Not sure about that.)

    [*]Sneezing divers would likely extinct fast because of 3, 4, 5, 6, and 7
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    Not that I can see. Boats/baskets/rafts/nets seems to have caused the end of most forage diving, and allowed humans to migrate to inland rivers and cold water coasts, where diving was more risky and less essential.
    [*]It does not help cutting surface time as suggested, because getting rid fast of the CO2 is not what decides about the needed surface time
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    I don't understand. Respiration is the reason for surfacing.
    [*]To my best knowledge other aquatic animals do not have any photic sneeze reflex (except of horses, who are not aquatic - they have a similar photo sensitive syndrome)
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    Horses are domesticated and have been selectively inbred for work/racing. Their sensitivity is not understood, may be earmites or parasites etc. and sunlight magnifies it, they don't have dark adaptation, rather they simply keep sneezing and sniffling for hours; while in affected humans, photic sneezing results in one or a few sneezes with pupillary accomodation (see Moken underwater vision) with no further sneezing until after further dark adaptation. There are parallels with the marine iguana, which sneezes out salt on sunny beaches after diving, they cannot backfloat due to being coldblooded in cold water, unlike humans at warm sea lagoons. I'm not sure, but possibly marine iguanas remain in apnea while swimming to shore, and then the sunlit sneeze breaks the apnea, changing back to aerobic breathing. (need to verify that)

    I suspect that sea otters, seals, sea lions and walruses have a higher sensitivity to sunlight than other mammals, so they may have a photic-induced exhalation between deep dives. However, their vibrissae whiskers are highly sensitive, so no doubt are very important detecting water/air pressure changes, so sunshine might be only a weak stimulus.

    [*]The photic sneeze might not work when surfacing in cloudy days, in shadow, or in clear water.
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    Regular fluffy clouds wouldn't stop the photic sneeze, thicker cloud cover might, especially towards sunset or sunrise. I think they dove mostly when the sun was high in the sky. Thick rain clouds = rain = no diving (flooding silty rivers with dead stuff polluted the lagoon for a day), no shadows in coral reefs, clear water more than 2 meters deep requires dark adaptation.

    The following comment relates to my thought that seashore human ancestors avoided diving during the rainy season due to temporary silt erosion and contamination and subsequent algal bloom of estuaries/lagoons; leaving the seashore to forage for higher ground vegetation, tree fruits/nuts and ochre/basalt/flint.

    "There is a Brazilian study (unfortunately I don't remember the reference here) that shows that black caiman (melanosuchus niger) and other caimans feed almost only on fruits during rainy season in the Amazon basin, when the fishes are scattered in the varzeas. So it looks like it is really a typical behavior (among these crocodilians)..." Tetrapod Zoology : Alligators eat fruit (bottom comment)

    Also the seafood foraging marine otter of Peru leaves the seashore to swim upstream to eat berries, I think only during the rainy season.


    [*]Photic sneeze is much more common at Caucasians than at others human races, showing it probably appeared later in the evolution
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    I know some Chinese guys with photic sneeze, so now I refer it as 20% temperate Eurasian, rather than Caucasian. "appeared later" is an assumption, it may have been widespread before 100,000 yrs ago but lost significance due to much reduced diving.
 
Untitled Document

The cetacean respiratory tract does not contain turbinate bones like other mammals, which enables them to forcefully exhale without risk of injury. [Humans do, so sneeze out the mouth. DD] Cetaceans can only breathe through their blowhole. Their oral cavity leads only to their digestive tract and their nares lead only to their respiratory tract. This specificity ensures that neither food nor water obstruct the respiratory tract (Marshall 2002).

Untitled Document


Human (aerobic) tidal volume 0.5 liter (c 8 % of total lung volume, ie, lower than in most terrestrial mammals & much lower than in full-time diving mammals), but this is on land. I have no idea about this in human divers, perhaps close to our vital capacity (4.8 l)? (MV)

That is what I think the lar. air sac contained in (20,000,000 years ago to 5,000,000 years ago) the Last Common Ancestor (LCA) of the Hominoid-Hominid, about 1/2 liter of air trapped in the laryngeal air sac, allowing exhale without the face sinking below the surface while vertical floating and bipedal wading while foraging. Further enlargement of air sacs in extant apes may have resulted from both larger total body size (adult male orang) and dominance vocalizations, but for initial float benefit, 1/2 liter was sufficient.

Then in human ancestors (but not in apes) about 4,000,000 years ago, the laryngeal air sacs were lost (while paranasal sinuses expanded and occiput density gained ) due to moving to more open water (reef lagoons) and adopting backfloating (no more vertical floating), with increased subcutaneous fat (for thermoinsulation) which required denser bones (as in Homo erectus/ergaster and neandertals) as ballast to maintain neutral buoyancy in seawater. At this point, vertical floating changed to diagonal treading and backfloat sculling, which is why many H erectus skull show keeling.

Because they were primarily slow foragers (not fast prey chasers) with stick & stone tools, both on land and in water, heavy boned bodies were not problematic, and a large tidal volume was not advantageous aerobically on land (compared to horses), but in water, respiration efficiency became significant as it limited foraging effectiveness beyond wading depth (especially of offshore reefs).

From what I figure, shallow diving was primarily conscious breath hold face dipping when prone with hooded nose, and by clamping the nostrils between finger and thumb when not in prone position, while deeper diving was mostly reflex driven where the sensorial nerves activated the respiration patterns, alternating the Mammalian Divers Reflex (MDR) and the Photic Sneeze Reflex (PSR), with the backfloating aerobic resting phase, the whole thing of which I refer to as the Aquaphotic Respiratory Cycle (ARC). So the (aerobic) Tidal Volume of Humans did not change so much, unlike most marine mammals. It remains to be seen what is the volume of air exchanged in a typical sneeze series, and if sneezes are extended if lung CO2 is high as compared to relatively low, and whether high CO2 in the body increases sensitivity in the trigeminal nerve.


Marine otter (not sea otter) info included, to compare a part-time marine animal (not so well adapted as the sea otter but more so than typical river otters). The sea otter sleeps backfloating, the marine otter sleeps in a ground burrow ashore.

DDeden

Lioncrusher's Domain -- Marine Otter (Lontra felina) facts and pictures

- smallest species in the genus Lontra
- hairs very thick & hard & semi-erect >< other otters (soft plush fur)
- undercoat hairs 12 mm in length
- guard hairs 20 mm (keep the undercoat dry when the animal is wet)
- no SC fat
- paws webbed
- soles devoid of hair
- claws short & blunt
- head small, flat
- muzzle short
- ears v.small c 1.5 cm in length , set very low
- nose wide, trapezoid-shaped
- nostrils widely-spaced, located to the sides
- whiskers thick, profuse , protrude from their muzzle
- 36 teeth large, adapted for slicing their food
- tail short, cylindrical-shaped , tapers off at the end
- 4 mammae


Food
- ... variety of marine life, esp.crustaceans, molluscs & fish
- avoid the abundant echinoderms: starfish, sea urchins...
- freshwater prawns are a favorite : they swim inland in freshwater streams
far above sea level to catch them
- sea birds & small mammals occasionally
- fruit of coastal bromeliad plants seasonally

They swim 100-500 m offshore , diving near rocks with abundant seaweed.
They descend 30-50 m 15-30".
Small prey is eaten in the water, with the otter laying on its back.
Larger prey items are taken to the shore, usu.is on its back carrying the
prey on its belly.
They have not been observed using tools like other otters.
The marine otter spends 60-70 % of its time hunting.

added: AAT = the most aquatic ape.

I'd actually prefer aquamarine, since humans and seas go together well, while no other ape/hominoid/hominid lives near saltwater.

AAT = the most aquamarine ape. That's not the same as saying "humans are aquamarine mammals" as it's only true in comparing humans to our closest genetic extant kin.

Now does anyone have anything to say about Diving and Surfacing efficiently?
 
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So, next time you stop a sneeze when your nose tickles, you'll be mimicking the effect of water pressure halting the exhale expulsion just like our diving ancestors did, which the non-diving ancestors of apes, monkeys and other terrestrial mammals never did.

Great apes will pick their noses, but don't clamp their nostrils shut with thumb and forefinger when in water or put their forefinger beneath their nose to prevent fast reflex oral exhaling/sneezing. (This is not speculation nor flights of fancy, it is biology.)

Humans do that. Dive safe. Our ancestors did. So may our descendants.

peace.

DDeden
 
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Hi

I would like to make the point that it is not natural for human beings to walk on two legs either. With most land animals the new-born is up walking within a few minutes, whereas the new-born human baby is totally helpless. It has to first learn how to crawl and when it has done that, it has to learn how to stand up and walk. In the Sea-Gypsy tribes of South-East Asia where people live on boats, the young learn how to swim long before they learn how to walk.

Another point is that although ATT is called the Aquatic Ape Theory, to be more accurate it should be called the Semi-Aquatic Ape theory. Human beings are adapted to live both on land and in the water. Yes, humans can live on land successfully. But if put into a water environment then humans can survive diving and foraging for food underwater. Like the Sea-people of South East Asia and the Ama and Haenyo divers of Japan and Korea.

The point is that humans need to be trained to walk upright on land in the same way they need to be trained to swim and dive underwater. The only reason why few people now live in the sea is that with the rise of civilzations and better farming methods, humans can obtain far more food from farming. And if people do use the sea, they nowadays obtain fish by using large nets, and so do not have to go into the sea.

But this was not true ten thousand years ago. In Europe and many other part of the world hunter/gathers found far more food in wet-lands and on the sea-shore, than they did in forests. So most people then were capable of living a semi-aquatic exsistance.

Humans have shown they can adapt to a wide range of habitats and this includes dry deserts or living in wet-land and the sea.

William Bond
 
wabond said:
Humans have shown they can adapt to a wide range of habitats and this includes dry deserts or living in wet-land and the sea.
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William, the fact that we are capable of doing something when taught and the assertion that we as a species are genetically adapted for it via natual selection are two very different things. The term 'adapted' has a particular meaning in this context: adaptation means gaining a set of genetically inherited traits via selective pressure on an evolutionary scale; traits that enhance one's ability to live and breed in a given environment. Showing that we can 'adapt to a wide range of habitats' is meaningless in the context of our adaptation - or lack thereof - to an aquatic environment (unless you're talking about our general adaptability, but that has nothing to do with an aquatic lifestyle and more to do with brain size & a spare pair limbs not dedicated to walking on).

Again, there is a lot of confusion about the scope of the claims you're making. First you say it should be renamed to the 'semi aquatic ape' theory then you talk about living at sea. The two scenarios would mean two entirely different sets of adaptations. Foraging in wetlands doesn't require dive reflex, collapsible lungs etc. We would probably have got by just fine with webbed feet and a long snout! Living at sea on the other hand would require a very high degree of specialisation; look at all the other mammals that manage to do this.

Also, it's a bit odd to claim that a few people still 'live at sea'. If you mean it in the literal sense then I have to say 'no, we don't': if we tried to we would drown. If you mean living on boats/oil rigs/hovercraft with jacuzzis on the foredeck then that's not really an aquatic lifestyle, is it?
 
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wabond said:
The only reason why few people now live in the sea is that with the rise of civilzations and better farming methods, humans can obtain far more food from farming.
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As above - I'd argue that the reason few people live in the sea is more to do with our tendency to drown than the effectiveness of farming. I'd love to be able to live 10km offshore and cruise past the local reefs on a regular basis, but I just don't think I'm physiologically suited for it no matter how much training I do (and I do a fair bit...)
 
Mullins

When i said living in the sea i did mean people living on boats or on the beach and foraging for food in the sea. The Sea-people of South East Asia, in places like Burma, Thailand, Malaya, Indonesia and the Philippines, live by diving for shellfish, and seaweed or foraging at low-tide. They live in boats or houses with long stilts on the beach. Unfortunately, the governments of these countries think they are primitive and are trying to 'educate' them.

The Sea people women have given birth to their children in the water long before it became a 'new-age' trend, and like i said the children learn to swim before they can walk. Scientific studies have been done on these Sea people show they have eyes that can see better underwater than normal people, but they don't see so well out of the water.

As for adaptation. Even though most people do not go in for breath holding diving at great depths, the fact that people can be trained to do this, means that these capabilities didn't come out of no-where. It would be totally unrealistic to believe that only modern humans are able to do this. It means that human beings in the past evolved these abilities because diving to deep depths was an evolutionary advantage in the past.

And the evidence from the past is there. Throughout the world archeologists have found large quantities of sea-shells near the coast. Not only in South Africa but places as remote as the coast of Siberia. In the Mediterranean archeologists have discovered hills only consisting of sea-shells. These shells could only be obtained by breath holding divers. In Florida archeologists discovered a small island in the swamps again made up only of sea-shells.

Even in foraging for food in shallow water there is still an advantage to be able to duck your head underwater and hold your breath for a long time. So even people living in swamps or foraging food in lakes and rivers will still learn how to hold their heads underwater for a long time.

Modern free divers are showing us all just how aquatic human being are, these abilities could only have come about through evolution. In a way they are re-discovering past abilities that we have forgotten.

William Bond
 
So we're sticking with the strong version of the AA hypothesis, i.e. that we are adapted for deep diving? Fair enough, and there do seem to be aspects of our physiology that make sense in that context. However it's a very big call to make and there are also quite a few problems with it, in particular adaptations that one would expect to see in a diving creature but which humans don't exhibit. The theory is on shaky ground and that's why I've been telling Wet he needs to be a bit careful about separating wild speculation from the points that are actually well founded. It also pays to acknowledge the limitations of what you can wring out of the evidence rather than charge off on flights of fancy to escape them. Thanks for actually engaging with what I'm saying.

I suppose I take a rather different view of the abilities demonstrated by the best freedivers. 113m (or 86m if we're excluding technology) seems deep to us precisely because we as a species are fundamentally crap at diving. Those depths are hardly remarkable compared to the performances of those species that are truly aquatic, and it's also hard to gauge where we stand relative to other non-aquatic mammals because they lack any inclination to train and compete alongside us. I reckon they're missing out, but there's just no reasoning with some creatures...

I don't think it's at all unrealistic to say that these top divers of ours can do what no humans were previously capable of, as they (we?) have access to a vast range of knowledge, technology and supporting infrastructure which make these dives possible. Not to mention a huge gene pool from which only a few talented individuals are being considered to represent us. Without the aids mentioned above, dives like these would be plain suicide.
 
Hi Mullins

I doubt if anyone would compare a human being with a dolphin or seal. These are truly aquatic animals. This sounds like a red herring to me. The human being is able to live on land, but is clearly able to swim underwater and dive to impressive depths, for a land animal. This is why i am saying that AAT should be called the semi-aquatic ape theory.

Whatever way you look at it, there was some time during human evolution where human beings lived on the coast or in wet-lands and found food in the water. And from this, human beings evolved to be able to swim underwater.

As for freedivers using modern technology, the point is that nowadays we have scuba gear but some divers found they can get by without this modern technology. There are freedivers who won't use any modern technology at all, and from this, we are relearning ablities we didn't know we had.

Also the reason why i am sticking to humans ability to dive, is that we are on a diver forum. I don't know if divers will be interested in other aspect of AAT. But i am sure many freedivers will like AAT as it supports what they have discovered.

And also many AAT ideas are theory, so if i mention them, we can only get into a dialoge of disagreeing with each other, with very little evidence to support either claim. Whereas when i discuss the human beings ablity to dive and swim underwater there is no way anyone can refute this.

You clearly don't like AAT, and you have the right to do so, if that is the way you feel. I personally like AAT because the theory seems to explain so many things about why humans and so different from other animals.

William Bond
 
I joined this very late and have not read the entire thread. The last two post seem to argue whether we evolved from the water or evolved to diving in the water. As evolution is such a slow process, it seems evolving to dive in water is less likely imo. Thoughout history there has been such a small population of people who dive for that evolution to reach out to so many other people.

No one in my family dives and certainly not breath hold training. Yet I have an interest in it and I'm getting better at unlocking my abilities. That seems to lead to a deeper reason than evolving to water adaptaion.

Maybe our DNA keeps that small bit of aquatic reflex because water is still a big part of our everyday life and it's a key element to our survival. We really don't know what other creatures have a diving reflex either. Most land creatures can not process the unknown, but when they do get into water, they usually suprise us with their ability. Perhaps they even suprise themselves.
 
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Hi Chris

It has taken us about 6 million years to evolve from a ape to a human. In that time we know very, very little about how we done this. There is a lot of theories but very few facts. The popular theory is that we evolved from apes when we came out of trees to live on the Savannah. That is only a theory and not supported by any facts.

AAT also claims we came out of the trees but instead of living on the Savannah, the claim is that we lived on the beach or in wet-lands and this is where we evolved to learn to dive and swim.

So if we accept AAT then it wouldn't be just a few people living a semi-aquatic life it would be the majority of people. The trouble is that at school we all have been taught the Savannah theory and told nothing of AAT, and so most people still accept the Savannah Theory as a scientific fact, without being aware of there is a far better theory of human evolution.

William Bond
 
[Moderators: if this post is too explicit, delete.]

OT: For the benefit of new members at DeeperBlue.com reading this thread, please realize that this website is a commercial for-profit enterprise, involved in the marketing of diving products and services to members, this is rather unlike the AAT yahoogroup, which is far more objectively oriented toward human ancestors associated with aquatic/marine littoral habitat, and research of the biology, comparative anatomy and physiology of humans vs apes and correlations with water adapted animals.

Stating that humans are well adapted to swimming and diving in the water is probably always going to get a reproach from a variety of (well meaning) people here at DB who gain income or sponsorship of swimming and diving gear. If I had income from these sources, I also would not want to be told that it was less than "essential" for diving. Business is business, and baby's birthday coming up soon... and all that. Gotta respect individual's priorities.

Suffice it to say that my research has found numerous indications in human prehistory that diving, backfloating, swimming and wading occurred among archaic humans, that this selected for better efficiency in foraging and that this was subsequently largely eclipsed by technological specializations mentioned elsewhere in this thread.

Enjoy diving!

DDeden
 
William, will respond to your post a bit later. Some of it I agree with, some I don't. It's not that I 'don't like' AA, I just take issue with some of (many of?) the more extravagant claims made in its name. If I was a staunch AA supporter I'd probably be even more inclined to rein people in. Reasoned criticism is helpful to a theory, not damaging. Wild speculation masquerading as fact and pressed into service of a theory on the other hand, is damaging and just gets in the way when you're trying to discover what the theory can actually tell you.

Wet, it's time for another "you're not serious.... are you??" post. You seem to be saying that I'm arguing against humans' aquatic adaptation because I'm trying to promote dive gear. Lest people who read this thread rediscover their aquatic ancestry and decide to cast off their expensive carbon fins, putting me out of a job I didn't have in the first place. This would have to be one of the most ridiculous things I've heard on DB and even trumps some of your previous nonsense. Well done.

ps. I just went over my financial records for the past couple of years and added up all the money I've made from freediving sponsorship. When you include contract payments, travel & accommodation allowances, fees for advertising and speaking appearances etc it comes to a total of $0.00 (note, that's gross).
 
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This thread is very entertaining. It appears to be an exercise in banging head into wall for Mullins :head :blackeye

Keep fighting the good fight for common sense and critical thinking mate, but I think that there are forces out there that you will never overcome.
 
Reactions: jay cluskey
Thud...thud....thud....

It's perverse, but I'm actually kind of enjoying myself. Kind of.
 
I hypothesise that you require a banana because of your distant relation to an ape.

As your dextrous fingers are so nimbly able to remove the peel from the banana, your ancestors must have been from a high-banana area. Therefore, the origin of our species is Coffs Harbour, Australia.

 
Reactions: immerlustig

I was speaking of the website. Sorry, I thought I made that clear.



Would you kindly indicate any "nonsense" relevant to Diving and Surfacing efficiently? Perhaps you are assuming or misunderstanding something.



For better or for worse, I guess. I am far more interested in Diving and Surfacing efficiently (that was the original agenda for starting this thread after all) than I am in anyone's profit/loss statements, even my own, for the time being.

Is there anyone amongst the 17,000 + members that is actually interested in the topic at hand? Otherwise I'll drop it, no point in arguing for the sake of arguing.
 
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Bananas may have originated in the Indonesian isles, including Papua, which was connected to Australia at times. Java Man had exceptionally dense bones (far denser than any ape) and used clamshell blades to remove meat from bovid bones in wetlands, per one analysis. Slow diving mammals typically have dense bones (eg. sea otter, manatee, walrus). Bucky Fuller (polymath and inventor of the geodesic dome) speculated that human ancestors had become reef divers at coral atolls somewhere between Australia, Java and Polynesia. Coffs Harbour sounds a bit south, but coasties did and do tend to move around a bit, so it's not illogical, just not verified with any fossils or artifacts. Yet.
 
Reactions: kmo

Cool. So can you clarify what the above means please? And which of the well-meaning people who reproach you are you referring to? Or are you anticipating future reproaches from those in the business of promoting dive gear? If so, don't think you have anything to worry about
 
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Reactions: jay cluskey
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