Marty Becker

Known as America's Veterinarian; Featured on Vetstreet

Michael Archer

Paleontologist Michael Archer is working to bring back his favorite extinct animal: the Tasmanian tiger.

Simon Lovell

English Comedy Magician, Card Shark Actor and Con Man

Daniel Pauly

Daniel Pauly is the principal investigator at the Sea Around Us Project, which studies the impact of the world's fisheries on marine ecosystems. The software he's helped develop is used around the world to model and track the ocean.

Jackson Galaxy

Host, "My Cat from Hell" & Author, "Cat Daddy: What the World's Most Incorrigible Cat Taught Me About Life, Love, and Coming Clean"

Jason Biggs

Actor Known For His Roles in the "American Pie" Series and on "Orange Is The New Black" Among Others

Alan Cumming

Emmy-Winning Actor Who Stars in "The Good Wife"

Ian Somerhalder

Actor Known for "The Vampire Diaries"; Animal & Environmental Advocate; Founder of The Ian Somerhalder Foundation

Martin Sheen

Award-Winning Actor Known for "The West Wing" & "Grace and Frankie;" Social Activist & Humanitarian

Bindi Irwin

Wildlife Conservationist & Daughter of Steve Irwin; Season 21 Contestant on "Dancing With the Stars"

Jim O'Heir

Actor Starring in the NBC Comedy Series "Parks and Recreation"

Rachelle Lefevre

Rachelle Lefevre is a Canadian actress. She played the vampire Victoria Sutherland in the first two films of the Twilight saga

Danny Trejo

Actor, Author, Activist & Restaurateur; Recovery & Intervention Counselor for Troubled Youth

Katie Cleary

Actress and Model; Founder of Peace 4 Animals and World Animal News

Kristofer Helgen

Zoologist & Curator of Mammals at the Smithsonian; Discovered the Carnivorous Mammal, the Olinguito

Paul McCartney

Former Member of The Beatles; One of the Most Successful Composers & Performers of All Time

Tom Hardy

English Actor Known for "This Means War," "The Dark Knight Rises," "Inception." & "Mad Max"

Tamron Hall

Award-Winning Journalist; Former National News Anchor for NBC News; Host of the "Tamron Hall Show"

Watch Where They Hide

Lisa Vanderpump

Entrepreneur, TV Personality, Author & Philanthropist

Lisa Vanderpump Tells Us About Her First Times

Diana Reiss

A professor of psychology at Hunter College and in the graduate program of Biopsychology and Behavioral Neuroscience of the City University of New York.

Sophia Bush

Actress, Humanitarian & Author

Torrey DeVitto

Actress, Model, Ambassador for NHPCO & Advocate

Julie Scardina

Animal Ambassador at Busch Gardens SeaWorld of California

Tracie Hotchner

The Radio Pet Lady & Pet Wellness Advocate

Dave Salmoni

Animal Planet Television Personality & Large Predator Expert

Paul Snelgrove

Paul Snelgrove led the group that pulled together the findings of the Census of Marine Life -- synthesizing 10 years and 540 expeditions into a book of wonders.

Sarah McLachlan

Singer-Songwriter & Activist

Pierce Brosnan

Actor, Producer & Activist; Best Known for His Role as James Bond

Mena Suvari

Actress Known for "American Beauty" & Author of "The Great Peace: A Memoir"

Matt Damon

Actor, Screenwriter & Producer; Co-Founder of Water.org; Expert Advocate on Global Water & Sanitation Crisis