Marie Magdalen Jenkins was born September 26, 1906 in Eldorado, Illinois. After attending Phillips University, she taught in elementary and secondary schools in Oklahoma until 1942. At that time she took vows as Sister Mary Scholastica in the Benedictine Order. She completed her Master's degree at Catholic University in 1951, and taught or worked in Catholic schools until 1957, when she left the Order and entered the University of Oklahoma. In the late 1950s and early 1960s she taught zoology there while completing her Ph.D. Dr. Jenkins came to the Biology Department of Madison College (now James Madison University) in 1962, and retired from there in 1975.

For thirty years before she retired, Dr. Jenkins conducted original research on planarians (flatworms), particularly the relationship between aging and reproduction. She discovered that, contrary to previous thought, planarians do not live forever, and she gained an international reputation as an expert on the animals. For several years in the early 1970s, Dr. Jenkins raised and sold planarians for laboratory use. In the late 1970s, an Italian researcher named a new planarian species after her (Dugesia jenkinsae), after identifying it among specimens she had sent him.

Although she had been contributing to the professional science literature, starting in the late 1960s Dr. Jenkins began to pursue seriously a lifelong interest in writing for a broader audience. In 1969 her first science book for children, Moon jelly swims through the sea, was published, followed by: Animals without parents (1970; The Curious mollusks (1972); Embryos and how they develop (1975); Kangaroos, opossums and other marsupials (1975); Goats, sheep and how they live (1978); and Deer, moose, elk and their family (1979). Several of these were listed in Bowker's second edition of Best books for children, in 1981. All are available in Special Collections.