Resembling a smudge more than an animal, a mysterious life form known as a placozoan has now joined other obscure and primitive creatures whose genomes are providing insight into how animals first arose more than 650 million years ago.
Called Trichoplax adhaerens, the creature’s genome sequence, reported in the Aug. 21 issue of Nature, has surprised [...]

There is a newly discovered life history among the 28,300 species of known tetrapods, or four-legged animals with backbones. A chameleon from arid southwestern Madagascar spends up to three-quarters of its life in an egg. Even more unusual, life after hatching is a mere 4 to 5 months. No other known four-legged animal has such [...]

Biologists at Harvard University have determined that some African frogs carry concealed weapons: When threatened, these species puncture their own skin with sharp bones in their toes, using the bones as claws capable of wounding predators.
The unusual defense mechanism is described by Harvard’s David C. Blackburn, James Hanken, and Farish A. Jenkins, Jr., in a [...]