Where does our moral sense come from? Those of a fundamentalist persuasion say “God,” and leave it at that, but a more interesting answer comes from research on the nonhuman primates we share ancestors with.

Economists used to say that people are self-interested and rational, maximizing whatever payday is within reach. But recent studies have blown that idea to smithereens. When people are given the choice of accepting or rejecting the split of some spoils that a partner offers—say, how to divide the $10 that researchers have given them in an experiment—they reject offers perceived as unfair. So if you offer me $2 and propose to keep $8 for yourself, I’ll walk away and leave us each with nothing—stupid, considering that I’m rejecting $2 in free money, but consistent with the emerging idea that humans have a strong, evolved sense of fairness that trumps immediate self-interest. Something like this probably underlies people’s tendency to punish cheaters, free-riders and noncooperators. The game has been played uncounted times in labs, and the basic finding is that proposers typically offer 40 to 50 percent of the pot, and responders walk away from any offer less than 20 percent.

Now there is evidence that a fine-tuned sense of justice—insisting on fairness at the expense of tangible rewards—may be uniquely human, rather than something our closest living relatives also have.

With the ubiquity of cell-phone and security cameras turning us into YouTube Nation, scientists, too, are putting cameras where no lens has gone before: on bird tails. Mounting little video cameras on New Caledonia crows, which are renowned for their use of tools, the researchers have captured footage that will make you think twice before deploying that old epithet, bird-brained.

Studying tool use is all the rage among animal behaviorists because it promises to shed light on animal minds and the origins of the human one. So far, scientists have seen green herons using bait (twigs, berries, discarded crackers . . . ) to attract fish, Egyptian vultures using stones to crack open ostrich eggs and the woodpecker finch of the Galapagos using a splinter or cactus spine to pry grubs out of holes.

And that’s just the birds. Primates other than humans are no slouches in the tool-using sweepstakes, either. Chimpanzees in the Tai Forest of Cote d'Ivoire and Bossou in Guinea use flat stones as anvils on which to crack rock-hard coula nuts with chunks of wood, chimps at Mahale and Gombe in Tanzania fish for termites with strips of bark, and chimps in Sierra Leone place smooth sticks over the thorns of kapok trees so they don’t get pricked while scampering around the treetops.

New Caledonian crows are tool whizzes in the lab, able, for instance, to bend a straight wire into a hook and use it to fetch a bucket containing food. But since the crows are nearly impossible to observe in their native habitat of forested, mountainous areas on their South Pacific island, the obvious question arises: How clever are the birds in their native state rather than the lab?

Enter the tail camera. It does not interfere with movement, and is shed when the birds molt, scientists at Oxford University report this afternoon in the online edition of the journal Science, so what it captures is probably the birds’ natural behavior and not something out of an avian reality show.

Of the 18 video-equipped crows, two adult males used at least three different sticks to poke around in leaf litter and grass, something never before seen. One male used a tool for more than 18 minutes, put it aside a few times to use his beak, carried it with him during a flight, then used it again. “As sticks are plentiful in forest habitats, these observations indicate that crows may keep particularly ‘good’ tools for future use,” write the scientists. Both male crows made tools from dry stems, also something crows had never been seen to use before. Other crows used sticks to reach into beetle burrows and scoop out beetle larvae. Another window into the animal mind.