When his wife Dorothy Jo died, he became an advocate for animal rights and of animal-rights activism, supporting groups such as the United Activists for Animal Rights and the Sea Shepherd Conservation Society.
Ketika istrinya Dorothy Jo meninggal, Barker menjadi advokat untuk hak-hak binatang dan gerakan hak binatang, mendukung grup seperti United Activists for Animal Rights dan Sea Shepherd Conservation Society.