Meerkat

While his compatrioits scuffle about in the sand for delicious scorpions or fat, tasty mice, one meerkat stands alone, bolt upright on an exposed perch, scanning for hawks with dark eyes wide, ready to call out at the first sign of danger. Like other such guards in the animal kingdom, these endearingly vulnerable meerkat sentinels have long impressed biologists as true altruists - creatures willing to forgo food and brave danger to protect others.
Now a study in the current Science suggests that these beasts may not be such adorable heroes after all. Researchers have discovered that meerkats abandon their hunting to act as guards only when their bellies are good and full. And they appear to do so, not as an act of noble daring, but because by being the first to see a predator, they can be sure of being the first down a hole and out of harm's way. Standing guard, researchers concluded, may be the safest thing to do once a meerkat has had enough to eat.
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Even the adorable meerkat may yet redeem itself as a bit of an altruist. Although being a sentinel may itself not entail great risk, it is hard to imagine a selfish reason for their giving a shout of warning before dashing for cover. . . .