Animals

Animals

Toothy valves control crocodile hearts

The odd cog teeth of the crocodile heart may be the first cardiac valve known to control blood flow actively.

Animals

Chicks open wide, ultraviolet mouths

The first analysis of what the mouths of begging birds look like in the ultraviolet spectrum reveals a dramatic display that birds can see but people can't.

Animals

Slavemaker Ants: Misunderstood Farmers?

A test of what once seemed too obvious to test—whether ant colonies suffer after being raided by slavemaker ants—suggests that some of the raiding insects have been getting unfair press.

Animals

Fishy Paternity Defense: Bluegill dads: Not mine? Why bother?

Bluegill sunfish have provided an unusually tidy test of the much-discussed prediction that animal dads' diligence in child care depends on how certain they are that the offspring really are their own.

Animals

Costly Sexiness: All that flash puts birds at extra risk

Distinctive his-and-her plumages increase the chance that a bird species will go extinct locally, according to an unusually far-ranging study.

Animals

Careful Coots: Do birds count their eggs before they hatch?

A coot may tally the eggs in her nest, a rare example of an animal counting in the wild, suggests a new study.

Animals

Secret Signal: Fish allurement that predators don’t see

In a rare demonstration of secret messaging in animals, a swordtail fish uses ultraviolet courtship signals that are invisible to a predator.

Animals

At last, a bird that nails killer chicks

For the first time, researchers have found a bird species—Australia's superb fairy-wren—that reacts when all its own chicks disappear and a giant imposter takes their place.

Animals

Techno Crow: Do birds build up better tool designs?

Researchers surveying tool use by New Caledonian crows propose that the birds may be the first animals besides people shown to ratchet up the sophistication of their technology by sharing design improvements.

Animals

Ants lurk for bees, but bees see ambush

A tropical ant has perfected the un-antlike behavior of hunting by ambush, but its prey, a sweat bee, has developed some tricks of its own.

Animals

Fish That Decorate: Females prefer nests with pizzazz

If scientists give foil strips to male stickleback fish, the fellows carry them back to their nests for decoration, and it turns out that females seem to like guys with lots of shiny stuff.

Animals

Vampire bats don’t learn from bad lunch

For the first time, a mammal has flunked a controlled test for developing a food aversion after getting sick just once, and that unusual creature is the common vampire bat.