All creatures breathe in some fashion, but how the job gets done has changed from fish to amphibian to reptile to mammal. Curt Stager and Martha Foley chart the evolution of animal respiration.

Earthworms, friend to lawn and garden, are actually an invasive species in northern forests, which developed in the worm-free environment of retreating glaciers 10,000 years ago. Martha Foley and Dr. Curt Stager discuss their return, and the consequences for boreal soil, trees and wildflowers.

Database analysis shows that winter, in addition to its other woes, is volcano season. Martha Foley wonders why.Dr. Curt Stager points the finger at the Pacific Ocean, which piles water on the North American coast and lightens the load on Asia. The stress comes out it crustal acne.

Trying to put nature back the way we found it can be more complicated than just leaving things alone. Dr. Curt Stager talks with Martha Foley about attempts to restore "green tree reservoirs," flood-plain forests that have been reduced 80 percent in size by human encroachment.

Animals, like humans, keep an eye on their fellows, particularly when the action is hot. Siamese fighting fish who witness a conflict treat the winners and losers differently.Martha Foley and Dr. Curt Stager talk about nosiness in nature.

Why would a heavy fur cape, like a lion's mane, be appropriate on a tropical savanna?As with male fashion in humans, it appears the that the lionesses of the Serengeti like it the thicker and darker, the better. Martha Foley and Dr. Curt Stager talk hair.

Much of human activity has a big downside for the natural environment. But sometimes, the problems we pose to nature can give a leg up to certain species. Martha Foley and Dr. Curt Stager discuss the upside of light pollution and cigarette butts.

Bird songs do more just decorate the air. Dr. Curt Stager talks with Martha Foley about Eurasian jays, who "spy" on each other's sounds for clues on where they might be able to raid a little food, and about the fairy wren that teaches chicks still in the egg a "family song," preventing imposters in the nest.

Besides making our food taste better, sodium chloride (salt) is necessary for our bodies to function. Martha Foley and Dr. Curt Stager whet their appetites on the science of salt.

It's a delicious flavor, for humans and deer alike, but it's also so much more. There's just something special about salt, a naturally occurring mineral that humans and many animals crave. Found naturally in its crystalline solid form, sea water and rock deposits left behind by ancient oceans, this chemical compound is among those that many of our cells need to survive.Conversation with Martha Foley and Curt Stager gets a little salty.