Gee those of us that are a certain age must remember being told in school that humans ability to use tools was one of the things that set them apart from mere animals.

Since then we've found out that just isn't true.

Many animals use tools they fashion themselves.

Now there's news of another species using tools. Interesting stuff...

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In the deep, lucid channels of Australia's Shark Bay, wild bottlenose dolphins have discovered tools, raising provocative questions about the origins of intelligent behavior, the nature of learning and the birth of technology.

There, dolphins in one extended family routinely use sponges to protect their noses as they forage for fish hidden in the abrasive seafloor sand, Georgetown University scientists reported earlier this month.

As best the researchers can tell, a single dolphin may have invented the technique relatively recently and taught it to her kin. The simple innovation dramatically changed their behavior, hunting habits and social life, the researchers found. Those that adopted it became loners who spend much more time on the hunt than others and dive more deeply in search of prey. The sponging dolphins teach the technique to all their young, but only the females seem to grasp the idea.

"It is indisputably tool use," says primate anthropologist Craig Stanford at the University of Southern California, an authority on animal cognition and behavior who wasn't part of the dolphin research group. "Despite the fact they lack hands and legs, dolphins make do."

For those seeking a glimpse of our own beginnings, the dolphins of Shark Bay offer a hint of the inventive impulse when our earliest ancestors first shaped destiny by fashioning implements with their own hands.

Tool use of any sort among wild animals is rare, difficult to document reliably and controversial. The line between instinct, ingenuity and intelligence is easily blurred by wishful thinking, experts caution. Field observations are often fodder for scholarly disputes. Even so, 10 primate species of monkeys and apes, along with 30 species of birds, are thought to use sticks, rocks or leaves as tools at least every once in a while.

Sea otters deliberately batter abalone shells with rocks to obtain the succulent meal inside. Some crabs, like shoreline seamstresses, cut up sponges and wear them for camouflage. Wild chimpanzees in Senegal hunt bush babies with makeshift spears, researchers at Iowa State University reported last year. Caledonian crows fish for insects with grass stalks and strips of leaves, while woodpecker finches hunt grubs with a cactus spine. Humpback whales weave nets of bubbles to snare fish in what some marine scientists contend is a form of communal tool use.

In the first in-depth analysis of this natural dolphin behavior, published in the online journal PloS One, marine biologist and psychologist Janet Mann at Georgetown University and her colleagues found that the dolphins of Shark Bay use their makeshift hunting masks more often than any other species uses tools, save human beings. "Tool use among this population is striking," says Dr. Mann, who has studied these marine mammals in the wild since 1989. "Spongers use tools more than any nonhuman animal."

The curious hunting habit first came to light decades ago when a local bay fisherman mentioned to marine biologist Rachel Smolker that he had seen a dolphin with an odd growth on its nose. Monitoring its movements through the bay's unusually clear waters, the researchers soon discovered that the sleek, air-breathing mammal was actually balancing a conical basket sponge on its beak.

At first, no one could figure out what a dolphin was doing with a sponge. From their vantage aboard a small dinghy, Dr. Mann and her colleagues eventually identified 41 dolphins who regularly used sponges to hunt, cataloging 1,295 dives in which they surfaced with sponges on their snouts.

Researchers were startled to realize that the dolphins of Shark Bay employed one living creature as a tool to help hunt another.

Not any basket sponge would do, the researchers soon learned. The dolphins might search for 10 minutes to locate one with the right conical shape to cap their nose, tear it free of its mooring, and then carry it to a preferred hunting ground along channels between 26 feet and 42 feet deep. "You can see that they are scattering the sand gently as they go along," says Dr. Mann. "When they startle a fish out of the sand, they immediately drop the sponge and go after it." They return to retrieve the sponge and pick up the hunt again, repeating the pattern.

"They really use these sponges as a foraging tool," says dolphin biologist Maddalena Bearzi, president of the Ocean Conservation Society in Los Angeles. "They discovered it could create an advantage in their foraging technique, and they pass it from generation to generation."

Only a few dozen dolphins use sponges to keep from scraping their noses, among the hundreds living in the bay, and that offered researchers an opportunity to compare creatures that use tools to others of the same species that do not.

Although the wild spongers all appear to be related, researchers at the University of New South Wales suggest that nurture, not nature, is the reason these dolphins use tools, ruling out genetic explanations for the behavior. Instead, they are convinced that sponging is passed from one generation to the next through the rote learning of imitation. Among bottlenose dolphins, mothers nurse their young for up to eight years, ample time for calves to absorb their mother's hunting tricks by observation. "This is an example of culture among these animals," says Dr. Bearzi. "This is part of the reason it is so important."

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Chimpanzees

Chimpanzees use spears to hunt.
Chimpanzees
Chimpanzees

So far, almost all of the dolphin spongers have proved to be female. "The sex difference is really striking," Dr. Mann says. "I don't know of another species where it is so dramatic."

Of the spongers' offspring, only the daughters could be seen still sponging once they reached maturity. The sons tried it but almost always abandoned it. Male dolphins rarely play a role in child-rearing and tend to fish in packs.

Only one older male dolphin continued hunting with a sponge. "He would go get a sponge and do it privately," Dr. Mann says. "It was like he was cross-dressing in private -- an old man out there sponging by himself."

For Dr. Mann, the discovery that dolphins too are tool users adds an unexpected dimension to the history of innovation, shedding new light on animal intelligence. Clever mimics and fast learners, dolphins have unusually large brains -- four times the size of a chimpanzee's and second only to humans in relative size. Dolphins even show evidence of self-awareness, by being able to recognize themselves in a mirror, some scientists argue.

"It speaks to this whole issue of creativity and learning and brain size," she says. "The number one question that drives me and others is, Why do dolphins have such big brains? What are they doing down there in the water that requires them to be so smart?"

* Robert Lee Hotz shares recommended reading on this topic and responds to reader comments at WSJ.com/OnlineToday. Email him at sciencejournal@wsj.com

A very interesting read...