Aquatic Ape 1998 documentary series

[wet]

Paleo-anthropology, early human ancestors swam, dove, waded, walked & ran at shores more than in forests or savannas.

YouTube - Aquatic Ape 1 - Documentary (Discovery...

YouTube - Aquatic Ape 2 - Documentary (Discovery...

YouTube - Aquatic Ape 3 - Documentary (Discovery...

YouTube - Aquatic Ape 4 - Documentary (Discovery...

YouTube - Aquatic Ape 5 - Documentary (Discovery...

[wet]

"new" evidence of clambakes 164ka in South Africa

Study: Early humans threw clambakes - CNN.com

in addition to handaxes found on an uplifted coral reef in Eritrea, east Africa 125ka.
They'll find more as they dive and dig deeper along the coasts. The caves and uplifted reefs are generally high above the previous sea level, so most of the artifacts were washed away or destroyed by erosion and recycled or covered by deposition or concretion into reefs.

[Paul Kotik]

To the starter and the posters to this thread:

Thank you, thank you, thank you, thank you <repeat 10**27 times).

[sea-wolf]

That documentary is really great. I have read many threads on the subject, Homo Delphinus, etc, but that's my first video. Thanks a lot.

[Apnea_Addict]

Thanks for those links !

I also found a video of the amazing swimming monkeys underwater:

YouTube - Monkeys Swimming Underwater

[naiad]

Fascinating. The AAT sounds plausible enough. There are still some things that I don't understand about it though. These are:

Nostrils which cannot be closed. Most aquatic mammals close their nostrils when diving. No animal uses a noseclip or pinches its nose, and few use sinus flooding.

Poor underwater vision. Although some people are apparently better off than others, including tribes who dive regularly, most aquatic animals have much better underwater vision than we do. Those which do not, or live in murky water, have other adaptations such as long whiskers (seals), echolocation (dolphins and whales), lateral line (aquatic amphibians).

[wet]

Originally Posted by naiad

Fascinating. The AAT sounds plausible enough. There are still some things that I don't understand about it though. These are:

Nostrils which cannot be closed. Most aquatic mammals close their nostrils when diving. No animal uses a noseclip or pinches its nose, and few use sinus flooding.

True, we can flare open our nostrils, but can't close them tight. The bell shape of the nose keeps air inside unless tilted, this allows prone shallow diving, but isn't so good for vertical diving.

The following is speculative, but seems to fit the known facts, and answers why our ancestors didn't develop closeable nostrils:

Before the diving era, about 20 - 5 million years ago, while the tailed monkeys were living in inland forest woodlands, there were hominoids (human and ape ancestors) living along coasts and in wetland forests that waded and floated vertically while gathering foods in and around the water (in addition to climbing and plucking fruits in the forest canopy), with inflateable laryngeal air sacs in the throat keeping the nose and mouth above the water surface (unlike the long-tailed macaque monkeys in the video). Their bodies developed some "amphibious mammalian" features (less fur, more bare skin areas, some skin-fat, complete loss of tail), the nose didn't, since it was kept above water, it was oriented upwards (like gorillas), with just a small fleshy cover (like chimps) in case the face got dunked while plucking plants and snails and floating fruit on the surface and in the shallows.

See Aaron Filler's website uprightape.net , which describes changes in hominoids 20ma including a shift in the spinal septum, which allowed upright locomotion. This fits with both hanging from branches and floating/wading, although he doesn't mention AAT specifically.
The Upright Ape - A New Origin of the Species: A Book that Revolutionizes Human Origins and Updates the Theory of Evolution

Gradually the ancestors of the apes expanded inland along gallery forests, but the ancestors of humans remained near the shores, with the nose becoming a pug nose and gradually enlarging, with a bony base, as surface swimming was increased. After a few million years of this, shallow diving in a prone position and plucking foods below was routine. Internal nasal-oral valves (velum, epiglottis, tongue, lips) kept water out of the lungs, rather than the external nostril valves more typical of aquatics, eventual loss of the air sacs and replacement with more hydrodynamic skin fat and hair at the voids, better breath holding, more flipper-like hands and feet (compared to apes), though never as specialized as seals, which have been more aquatic far longer than humans were and actively chased their mobile prey).

Humans have ventral oriented nostrils, this is only shared with sea otters AFAIK, and likely indicates habitual backfloating between diving, H. neandertals and H. erectus had large air filled sinuses in the forehead and dense keel-shaped occiput bones (skull rear) which suggests backfloating habitually, and indicate a change from prone swimming to more vertical diving.

Did they dive empty lung and/or flooded sinus and/or exhaling with a sunlight induced sneeze? No one knows, but I haven't seen clear indications that they did not, and I think it was indeed part of the daily diving experience, up until the development of simple dug-outs from hollow logs and fiber nets about 100-70,000 years ago, whereupon the diving skills gradually became less important and boating and fishing and larger settlements altered the society in various ways.

Reminder, AAT means human ancestors were the most aquatic ape, not the most aquatic mammal. Even during the most aquatic period, they were still only part-time divers, never completely reliant on seafood, unlike long time marine mammals like dolphins. I'd guess maybe 1/3 of the diet was seafood on a daily basis, sometimes more, sometimes less (fruit season, nut season). But even if it was only 1/10 of the diet, if it happened every other day, over long periods, it would show strong selection eventually.

Poor underwater vision. Although some people are apparently better off than others, including tribes who dive regularly, most aquatic animals have much better underwater vision than we do. Those which do not, or live in murky water, have other adaptations such as long whiskers (seals), echolocation (dolphins and whales), lateral line (aquatic amphibians).

Human ancestors were not as aquatic as full-time specialized marine mammals (dolphins, seals) and fish, they were always partly terrestrial and slightly arboreal. The food the collected in the water was not fast moving, it was sessile molluscs, vegetation and slow moving whelks, crustaceans etc. Most likely they used small simple tools, pebbles (like sea otters), stone blades, empty seashells (like capuchin monkeys do to open oysters at mangrove forests), wood/bamboo spears (as chimps do when hunting bushbabies in hollow trees).

In general, human eyes are like other primate eyes, but are larger, more lateral than vertical oriented (unlike apes), have thicker eyelids (keeping the eyes warmer at cool depths), and have exposed white sclerae (whites of the eyes), all which seem to relate to diving and shore life. They were slow divers that probably dove down from 3 - 20 meters normally, in quiet clear tropical reefs, not murky mudholes. I doubt they dove as much during the rainy season when more mud was in the water, since that is also when occasional crocs and sharks would tend to bite first and check second. More likely they would have been undercover in caves or rockshelters or perhaps, like orangutans do during rain, put leaf lids on their nests (dens) and just sleep, waiting for the sun to return.

I think the modern desire to go to sunny beaches and clear waters has deep roots.

[simple questions but hard to answer without explaining the whole thing]

Tangvoranuntakul,P
(my interpretation in [...])

Humans and chimpanzees share >99% identity in most proteins. One rare
difference is a human-specific inactivating deletion in the CMAH gene,
which determines biosynthesis of the sialic acid N-glycolylneuraminic
Acid (Neu5Gc)...[which in testing showed: diminished acoustic startle response
[the change from gasp/scream & air sac inflation during vertical floating to non-inhaled MDR empty lung diving?], abnormalities of the inner ear [better hearing underwater, poorer in air? -> primitive "sonar"? humming/song?] occurred in adults, which also showed delayed skin wound healing [SC fat (blubber?) development?]. Loss of Neu5Gc in hominid ancestors approximately 2-3 million years ago likely had immediate and long-term consequences for human biology.


DDeden

[naiad]

Thanks for the explanation.
It seems most likely that early humans foraged for food in warm, clear and shallow water.

[wet]

Originally Posted by naiad

Thanks for the explanation.
It seems most likely that early humans foraged for food in warm, clear and shallow water.

Yep. Seawater, based on the evolutionarily recent reduction of eccrine sweat (salt) skin glands in humans, gorillas and chimps and partial lobulation of some human fetal kidneys. Freshwaters inland were probably hazardous due to large predators and waterborne parasites, which is why apes usually stick to the trees and only wade occasionally.

I figure they typically resided at pocket beaches fronted by reefs and backed by cliffs with rock overhangs and seeping springs, with a few palms, mangroves and figs, etc. They may have traveled inland at times hunting and gathering foods, flint, obsidian, ochre perhaps a hundred miles for periods, but I don't think they regularly lived inland due to big cats, until weapons and fire were well controlled, and dugouts allowed scent-free non-disruptive transit.

The depths dove probably depended on the shore structure, 0 - 10 meters no doubt, deeper than that remains unknown but if there was rich foods in deeper reefs it would have attracted deeper dives. Sea otter adult males and walruses dive to 100 meters, so I view that as the theoretical maximum.

DDeden

[wet]

I've been informed (by Dana M.) that the human circadian rhythm is about 25 hrs. long (not 24), and the daily tidal period is about 24 hours and 50 minutes. This fits with daily seashore foraging in ancient humans, with slight divergence since the last 50,000 years or so due to technology, agriculture, boats, etc.

Can anyone verify this close match-up between circadian and tidal rhythms?

DDeden

[trux]

Originally Posted by wet

I've been informed (by Dana M.) that the human circadian rhythm is about 25 hrs. long (not 24)

Ha! That's quite interesting, I always wondered why I am permanently prolonging my day until I get to bed at 7AM and have to restart the rythm anew. So if you want a confirmation from me, you have it

[wet]

Thanks, the correlation so far seems a bit weak, tying circadian with tidal rhythm, but still looking on the net.

[Bill]

I don't know about proving but it's easy to convince someone by observation. Every living thing on the planet is in step with the sun and the moon. One day a flock of birds flies over and the next day they're about 45 minutes late. Even the insect activity (and the ghekos) syncs with the moon, later each night.

[wet]

Response to Dana's suggestion on tidal-circadian rhythms:

PT: This is outright nonsense. Rhythms are governed by dark/light cycles and the rhythm can be variable. Consider beavers, an actual aquatic mammal (as opposed to terrestrial species like humans):

http://www.fs.fed.us/r2/projects/scp...icanbeaver.pdf
North American Beaver (Castor canadensis): A Technical Conservation Assessment
...
In winter, beavers may display a circadian rhythm of 26 to 28
hours when living under pond ice in the shelter of the lodge (Wilson and Ruff 1999). ...

The 24 hour 50 minute figure for humans is the free running, i.e., UNregulated, period. Humans today, much less our ancestors, do not live in an unregulated world. We go by the night day alternation (which is actually a few minutes under 24 hours). Modern living - economics, jobs etc - seriously disrupt sleep cycles. The real fatal flaw in this rubbish follows from this:

"It occurred to me that an aquatic ape living by the sea would fall into that rhythm, presumably to be ready at each low tide to gather mussels, clams, crabs, etc." (Dana M.)

Here's a tide schedule for the city of Seaford in the state of Virginia:

Tide schedule
Times for high and low tides vary quite a bit. They do not occur at the same time each day. Consequently, we could not time out circadian rhythm to coincide with tidal schedules.

DM: Of course the workaday circadian rhythm of modern humans is governed by light/dark and myriad other cues. No argument there. It's the rhythm in the absence of those cues that intrigues. Without those cues humans seem to fall into a daily sleep/wake cycle of ~25 hours. Interestingly, even with all of the cues many people still feel like they should be on a 25 hour cycle, that it's more natural for them.

I merely suggest that this apparently natural human rhythm conforms to a "daily" tidal cycle, which includes two high and two low tides. The very website for the tides of Seaford, Virginia that Mr. Travsky
employed to refute my argument actually confirms it. Look at the time of any tide. The next tide of the same type (high or low) will be 12 hours and ~25 minutes later, and the next after that will be 24
hours and ~50 minutes later, creating a tidal "day" of 24 hrs 50 min. That pattern, with few variations, occurs the world over, has done so for eons, and is suspiciously similar to our natural circadian rhythm of ~25 hours.

Mr. Travsky's beaver example is interesting, but not directly applicable. Beavers are creatures of lakes and streams which do not exhibit tidal variation. The sea coast does. And that tidal rise and fall would have been of critical importance for any human ancestor trying to gather food or perform other activities. A sleep/wake cycle that evolved to conform with the tides would make sense.

My argument is not against the obvious fact that modern humans are regulated by the sun and the clock and not the sea, but rather that we apparently retain vestiges of a circadian rhythm from a distant
past that was lived on a sea coast, a daily cycle that was then regulated by the tides.

MV: Yes, excellent idea, but we first have to know what are the diurnal rhythms in other animals incl.sea-otters, coastal otters (Aonyx) etc. If it is as Dana thinks, our littoral phase seems to have lasted until *very* recently, perhaps even after the sapiens LCA.

DD: I tend to agree with Dana, that humans have maintained a tidal influence in our behaviour, although we mostly lost the seashore daily diving/foraging long ago.

Here's something on circadian rhythm disruption due to daylight saving time change of one hour:
A Blog Around The Clock : Daylight Savings Time worse than previously thought


DDeden

[wet]

Parallel to whale evolution: bone density increase in human ancestors and whale ancestors.

Whales originated from aquatic artiodactyls in the Eocene epoch of India