Ok - This is a good one.

[Minimalist]

http://apnews.excite.com/article/20100811/D9HHFFLG3.html

NEW YORK (AP) - Two ancient animal bones from Ethiopia show signs of butchering by human ancestors, moving back the earliest evidence for the use of stone tools by about 800,000 years, researchers say.

The bones appear to have been cut and smashed some 3.4 milion years ago, the first evidence of stone tool use by Australopithecus afarensis, the species best known for the fossil dubbed "Lucy," says researcher Zeresenay Alemseged.

"We are putting stone tools in their hands," said Alemseged ("Uh-lems-uh-ged") of the California Academy of Sciences, who reports the finding with colleagues in Thursday's issue of the journal Nature.

When does a rock become a tool?

[Rokcet Scientist]

When does a rock become a tool?

When this has been done to it: http://archaeologica.boardbot.com/viewtopic.php?f=11&t=2698

[Minimalist]

I submit that a rock remains a rock right up to the moment that someone or something intentionally uses it to accomplish a task. Then, it becomes a tool.

[uniface]

When it's modified.

That was the argument before about animals never using "tools." Then they found chimps modifying grass to use in fishing for termites and the whole "man is the only tool-making animal" assumption collapsed.

[Minimalist]

If you are trying to drive a stake into the ground and pick up a handy rock to do it, you have just converted that rock into a hammer. The only modification is from the impact of the rock on the stake and that occurs after you have used it.

The article that Digit posted goes into more detail about the marks. Apparently it wasn't just crushing bones with a hammer stone. There were cut marks as well. That becomes a whole other thing.

[Rokcet Scientist]

Apparently it wasn't just crushing bones with a hammer stone. There were cut marks as well. That becomes a whole other thing.

Since it's been established that chimps use hammer stones and anvils for nuts, and that they also appreciate fresh meerkat or colobus sushi every now and then, it won't be long before they put 2 and 2 together and start crushing bones with those hammer stones. To get at the marrow.
That would put Lucy, in developmental terms, just one step ahead of chimps on the evolutionary ladder!
But if AAfarensis cut, that was another step. Opening up a lead, as it were.

[Minimalist]

Sea otters also use rocks as hammers.

Perhaps, the cognitive spark was the ability to cut rather than simply smash?

[Rokcet Scientist]

Sea otters also use rocks as hammers.

Minor detail, major difference TBH: sea otters use rocks as anvils, not as hammers...

Perhaps, the cognitive spark was the ability to cut rather than simply smash?

One of many "cognitive sparks". Another was the invention of cooking, possibly between 2 and 3 MYA (the emergence of HH and HE), which strongly mitigated dental wear (and consequently increased lifespan), and which increased the nutritional uptake of the body, whence more nutritional energy became available for the development and operation of the brain (the body's main energy hog).

Arbitrarily it could be argued that cooking made us human...

This may be graphically illustrated by, on the one hand, the considerable increase of the skull/cranium size, while OTOH hominid's bite/jaws/dentition sharply decreased in size (e.g. the slow devolution of wisdom teeth).

[Minimalist]

An anvil is still a tool.

Arbitrarily it could be argued that cooking made us human...

I wish someone had told my wife that.


ba-bump-bump!

[Rokcet Scientist]

An anvil is still a tool.

Then so is the tree that the elephant and the bear scratch on. Or the submerged pebble beach for the orcas. Or the mound that the cheetah observes from. Etc. etc.

It seems that the definition of "tool" could do with some further refining. I propose that a tool is a tool if it is used 'manually', i.e. handled with the limbs.

[Tiompan]

An anvil is still a tool.

It seems that the definition of "tool" could do with some further refining. I propose that a tool is a tool if it is used 'manually', i.e. handled with the limbs.

That's a bit limbcentric ,there are human artisans and artists that are limbless , likewise animals that use what is available e.g. crows /beaks .

George

[Minimalist]

I could actually buy the "tree" as a tool in that case since the animal is actively using it to accomplish a task. I don't think one could stretch the analogy to include a hilltop vantage point but you're on the right track, R/S.

And George's point is well taken. We have advanced to the point where quadriplegics can access computer screens. Definitely a tool.

[Tiompan]

An anvil is still a tool.

It seems that the definition of "tool" could do with some further refining. I propose that a tool is a tool if it is used 'manually', i.e. handled with the limbs.

That's a bit limbcentric ,there are human artisans and artists that are limbless , likewise animals that use what is available e.g. crows /beaks .

George

Sorry that was a bit misleading ,I mean crows use their beaks to manipulate tools and the beak is not considered a limb .
George

[Rokcet Scientist]

Yeah, I know that video where the crow bends some wire into a hook and uses it to fish a morsel out of a glass tube.

They use pedestrian crossing points with traffic lights too... (to get nuts run over and thus cracked).

In the strictest sense of the word that would mean a pedestrian-crossing-point-with-traffic-lights is a tool.

I submit that 3.4 MYA there very few computers to be operated by quadriplegics.

[Tiompan]

Yeah, I know that video where the crow bends some wire into a hook and uses it to fish a morsel out of a glass tube.

They go one better than that , using one sized stick to obtain another sized stick that is then used to obtain food ,the original sized stick being useless for the job .

George