Marker's family resettled in Palos Verdes, and later in San Jose, both in Northern California (USA), in time for her to finish high school at age 16.
[1] She started college early at San Francisco State University, intending to become a veterinarian, but the emerging wine industry in the Napa Valley caught her eye.
In 1974, to make ends meet, she began working at the newly opened local exotic animal park, Wildlife Safari, in Winston Oregon, where her tenure spanned 16 years.
Marker decided to extensively study the ten cheetahs at Wildlife Safari and began developing what eventually became the most successful captive breeding program in the country.
[1][2] She had inadvertently become one of the world's foremost experts on cheetahs, and began teaching zoo keepers and other captive breeders her techniques, and slowly expanded her research.
[1] When Marker returned with Khayam to the U.S. several months later following their successful research project, they traveled regionally and nationally making public appearances to generate awareness for the cheetah's plight.
[3] In 1990, Marker founded the Cheetah Conservation Fund (CCF), which began as a research outpost in a small farmhouse on some land in Otjiwarongo, Namibia.
[4] Marker saw the problem of saving cheetahs as a holistic issue, in which local communities, farmers and governments needed to participate together for mutual goals.
She created programs to aid farmers by providing free training in predator identification and livestock husbandry techniques to increase understanding and decrease losses.
[4] 2006 saw the creation of Future Farmers of Namibia, a program which educates and promotes sustainable farming cooperatives using an integrated system of non-lethal wildlife and ecosystem management.
[4] Plans are in the works and funding is being gathered for the purpose of building a large, fenced nature reserve, which will be the first national park in Somaliland, on which the rehabilitated cheetahs can be released to live wild again.
[1] Marker and the CCF team continues to educate, fundraise, develop holistic programs, and work with scientific bodies, governments and individuals around the world for the conservation of cheetahs in the wild.
[3] In 1995 she became the Species Coordinator for the Cheetah African Preservation Program, and in 1996, a member of the Waterberg Conservancy Executive Committee, and the Namibian Veterinary Association.
[6] Marker has authored or co-authored numerous scientific papers, across a range of topics, recently including: Recommendations for the rehabilitation and release of wild-born, captive-raised cheetahs: the importance of pre- and post-release management for optimizing survival.