Marine biologist Colleen Reichmuth says that few mammals can match the vocal talents of the walrus. Produced by David Levin. Original interview by Doug Hamilton. Learn more at pbs.org/nova NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, the Lockheed Martin Corporation, and PBS viewers.

In this episode, biochemist Erika Ebbel describes how a mentor helped her transform into a scientist when she was 11 years old. Produced by David Levin and Rob Chapman. Original interview by Josh Seftel and Tom Miller. Exclusive funding for "The Secret Life of Scientists & Engineers" provided by the Alfred P. Sloan Foundation. Learn more at pbs.org/nova/secretlife NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, the Lockheed Martin Corporation, and PBS viewers.

NOVA scienceNOW's Dean Irwin discusses what he learned about this new computer technology while producing his story on digital art authentication. Podcast produced by David Levin. Music by Jeff Allen. NOVA is produced by WGBH in Boston. Funding for NOVA scienceNOW is provided by the National Science Foundation, the Howard Hughes Medical Institute, the Alfred P. Sloan Foundation, and PBS Viewers. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, the Lockheed Martin Corporation, and PBS viewers. This material is based upon work supported by the National Science Foundation under Grant No. 0229297. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. For more fun science stories, visit our Web site at http://www.pbs.org/nova/sciencenow

In order to develop from an embryo, animals as different as fruit flies and humans call on a nearly identical set of genes. But how does this one common genetic toolkit create so many different species? It turns out that it's not the genes you have-- it's how you use them. Podcast produced by David Levin. Original interviews by John Rubin. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and PBS viewers. To learn more, go to pbs.org/nova/evolution

After Pluto was discovered in 1930, it enjoyed the title of planet for more than 75 years. But in 2006, that all changed. At a meeting in Prague, the International Astronomical Union adopted a new definition for planethood, leaving the solar system with only eight planets. But not everyone agrees with its decision. In this podcast, planetary scientist Alan Stern talks to us about Pluto’s demotion, and why he thinks it should be back on list of planets. Podcast produced by David Levin. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, the Lockheed Martin Corporation, and PBS viewers. For more information, visit: www.pbs.org/wgbh/nova/space/pluto-files.html

In this podcast, biologist Maydianne Andrade explains that sexual cannibalism-a gruesome mating behavior shown of Redback Spiders-is a prime example of how evolution works. Podcast produced by David Levin. Interview by Josh Seftel. Funding for NOVA scienceNOW is provided by the National Science Foundation, the Howard Hughes Medical Institute, the Alfred P. Sloan Foundation, and PBS viewers. This material is based upon work supported by the National Science Foundation under Grant No. 0229297. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and PBS viewers. For more fun science stories, visit our website at pbs.org/nova/sciencenow

In the months after 9/11, New York City faced a difficult decision. What should it do with the site where the twin towers once stood? For architecture critic Paul Goldberger, there was only one choice: rebuild. Podcast produced by David Levin. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. For more science stories, visit our website at pbs.org/nova

Could permafrost under Martian soil be the key to finding life on the red planet? Chris McKay, a planetary scientist for NASA, thinks there's a good chance we'll see evidence of ancient microbes if we just follow the ice. Podcast produced by David Levin. Interview by Anna Lee Strachan. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by ExxonMobil, David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. For more fun science stories, visit our website at pbs.org/nova/mars

For thousands of years, people around the world have modified their bodies with tattoos and piercings. But some cultures, like the ancient Inca in Peru, took that practice beyond skin deep. They sometimes used ropes and boards to slowly change the shape of human skulls. It’s a process called "cranial modification" In this podcast, bioarcheologist Valerie Andrushko explains. Podcast produced by David Levin. Original interview by Melissa Salpietra. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by ExxonMobil, David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. To learn more, go to pbs.org/nova/machupicchu.

In this podcast, marine biologist Roger Hanlon explains why octopuses are masters of camouflage. Podcast produced by David Levin. Interview by Susan Lewis. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by ExxonMobil, David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers. Learn more about the remarkable camouflage of octopuses--and their cousins, cuttlefish--on pbs.org/nova/camo.