Posts Tagged ‘000 BP’

Pleistocene Gray Whale (Eschichtius robustus) Calving Grounds off the Georgia Coast

September 21, 2015

During warm climatic phases of the Pleistocene, the north polar ice cap mostly or even completely melted.  The Arctic Ocean became an ice free corridor when interglacial summers were warmer and longer than those of the 21st century.  Many species of marine mammals used this ice free corridor as a migratory route between the Atlantic and Pacific Oceans.  A study of gray whale genetics suggests the gray whale enjoyed a gene flow between Atlantic and Pacific populations until the Last Glacial Maximum when the polar ice cap expanded and blocked the Arctic Ocean corridor.  It remained blocked from about ~30,000 BP-~10,000 BP.  Then, the corridor began opening intermittently and there was some mixing of populations early during the Holocene.

Human hunters extirpated the Atlantic population of gray whales by 1620.  It’s amazing how fast this was accomplished.  Whalers eliminated this population about a century after bringing their hunting technology to the American side of the ocean.  Humans almost overhunted the Pacific population into oblivion, but laws outlawing the practice saved the species, and populations are on the rebound.  Present day global warming is causing the Arctic Ocean corridor to open intermittently again.  Gray whales are using this corridor again and have recently been spotted in the Atlantic Ocean.  Gray whales may recolonize the Atlantic Ocean because of global warming.

Human divers discovered fossil evidence of gray whales off the coast of Georgia.  A gray whale jaw and jaw fragments from another individual were found on JY Reef located to the east of St. Catherine’s Island.  Today, this site is in deep water, but at the time these whales died, it was a shallow shell bed located near the shore.  One of the specimens dates to 41,000 BP, and the other was found embedded in oyster shells dated to 48,000 BP.  The vertebrae of an unidentified species of whale was also found here.

Some scientists hypothesize gray whales used the warm waters off the Georgia coast for breeding and calving, much like the small surviving population of right whales (Eubalaena glacialis) does today.  Killer whales probably hunted the whale calves as seen in the below video.  Gray whales migrate to cooler waters to feed.  During cooler phases of the Pleistocene this migratory route may have been shorter.

Video of a mother gray whale protecting her calf from a >2 hour killer whale attack.  Scenes like this likely occurred off the coast of Georgia until ~1620 AD.

Scientists are searching the continental shelf off the coast of Georgia for subfossil evidence of the gray whale barnacle, Cryptolepes rhachianecti.  This would be additional evidence for the former presence of gray whales here.

CETACEAN - WHALE - GRAY WHALE WITH CRYPTOLEPAS RHACHIANECTI - SAN IGNACIO LAGOON BAJA MEXICO (5).JPG

Gray whale barnacles.  Gray whales help spread the species and provide protection from predators such as starfish, sea worms, and fish.

Gray whales survived the climatic fluctuations of the Pleistocene, but in the Atlantic they couldn’t withstand 100 years of human hunting.

See also https://markgelbart.wordpress.com/2013/03/25/pleistocene-fossils-found-on-the-georgia-bight/ and https://markgelbart.wordpress.com/2014/09/12/the-paleoenvironment-of-the-georgia-bight-when-it-was-above-sea-level-80000-bp-7000-bp/

References:

Alter, S. Elizabeth; et. al.

“Climate Impacts on Transocean Dispersal and Evolution of Gray Whales from the Pleistocene to 2100”

Molecular Ecology April 2015

Noakes, Scott; Nicholas Pyenson, and Greg McFall

“Late Pleistocene Gray Whales (Eschrichtius robustus) offshore Georgia, USA, and the Antiquity of Gray Whale Migration in the North Atlantic Ocean”

Palaeogeography, Palaeoclimatology, Palaeoecology 2013

Deep Sea Fishing 42,000 BP

December 7, 2011

The Jerimalai shelter during excavation <i>(Image: Susan O'Conner)</i>

Jerimalai Shelter in East Timor, Indonesia.  This is where archaeologists found the remains of deep sea fish caught by humans 42,000 years ago.

The people capable of deep sea fishing in what’s now Indonesia 42,000 years ago may have been related to the ancestors of Australian aborigines.

Many archaeologists underestimate the technological capabilities of primitive men.  Most are convinced that early men could not traverse great nautical distances, despite the known presence of aborigines on the island continent of Australia as early as 50,000 BP.  The lack of marine technology among Australian aborigines, who could barely master building a raft that could stay afloat on a river, has long puzzled them.  Likewise, many reject the hypothesis that some or all American Indians are descendents of people originally arriving via coastal routes. I don’t understand why they reject this possibility.  People able to construct fabulous boats may have made the decision to move inland.  Without a written language, the knowledge of how to navigate across great oceanic distances could have been lost in 1 generation.  All it would take to lose the technology would be the death of a few men with the know how.  Oral tradition may have included memorized story telling, but reciting the steps of how to build a marine worthy vessel would have been too dry to sing around the fire at night.

Evidence that men were capable of deep sea fishing as long as 42,000 years ago was recently unearthed at the Jerimalai Shelter in East Timor, Indonesia.  Scientists discovered 38,000 fish bones from 23 different species including those that primarily inhabit deep ocean–tuna, shark, and parrottfish.  (As far as I know, the complete list hasn’t been published yet, or I surely would have that information on my blog.)  The fish bones date to 42,000 years BP.  A fish hook made out of a clam was found here, but this artifact only dates to about 16,000 BP.  How the more ancient fishermen caught tuna is a complete mystery.  No fish hooks of that age have been excavated here, and of course hand lines and nets are organic and have probably decayed into dust.  It’s surprising that they were able to successfully catch tuna.

Tuna grow even bigger than this.

The Pacific tuna (Thunnus orientalis) is a fast warm blooded fish capable of swimming at speeds up to 40 mph.  They grow to 500 lbs., though the ones the ancient fishermen caught were juveniles much smaller than their maximum size.  Still, the ability to navigate a boat into deep water, catch large strong fish, and return to shore is amazing, considering the primitive technology they utilized.

Archaeologists are also aware of another amazing oceanic journey that took place during the Pleistocene.  Stephen Loring, a museum anthropologist, examined the Manley projectile point, an artifact originally found in Vermont, and he had a eureka moment.  He knew this type of arrowhead was made about 12,000 years ago.  But he realized this particular one was made from Ramah chert–a kind of rock found only in Labrador.  (All rock is 99.9% silica.  Geologists can determine the origin of a rock by analyzing the remaining .1%)  Labrador is 1000 miles from Vermont.

Ancient mariners stumbled upon quality chert for tool making 12,000 years ago while cruising the coast of Labrador.

Blade made out of Ramah chert.  The Ramah chert blade comes from rock only found in Labrador.  This blade was made about 2800 years ago, but the Manley projectile point was found in Vermont and dates to about 12,000 years ago.  The land route at this time was blocked by glacial ice.  That means ancient people traveled 1000 miles along the coastal waters to reach the stone quarry.

The only way an Indian could travel back and forth from what’s now Vermont to Labrador 12,000 years ago was by sea because the land route was blocked by a mile high glacier and meltwater streams and ice impeded a sea shore journey.  Moreover, they had to navigate in and around numerous icebergs, so their route was at least 1000-1600 miles.  Archaeologists argue amongst themselves over whether the ancient mariners paddled or sailed, but they have no doubt the journey was accomplished at least once. 

Archaeologists are searching for evidence that Paleo-indians colonized America via a coastal route, but the proof will be difficult to find.  Sea levels rose following the end of the Ice Age, and any evidence that exists is deep underwater.  Boats made out of skin and wood have likely long since decayed into nothingness.

Reference:

Guest, Amy

“A Story of Ancient Mariners”

Mammoth Trumpet (26) 4 October 2011