Officials at the St. Louis Zoo are attempting to solve a motherhood mystery after a 62-year-old ball python laid eggs despite not having contact with a male python for more than 15 years.

The zoo said keepers were shocked when the snake, the oldest of her species to ever reside at the zoo, laid eggs during the summer.

Herpetologists said reptiles have been known to reproduce asexually through a process known as facultative parthenogenesis, and female snakes have also been known to store sperm from a sexual encounter for "delayed fertilization."

"Without genetic testing, zoo staff won't know if this ball python reproduced sexually or asexually, but they intend to find out," the zoo said.

Officials said keepers are caring for the eggs, and samples will be sent for genetic testing to determine their origins.

Mark Wanner, manager of herpetology at the zoo, said python's eggs also were surprising because of the python's advanced age. He said the snake might be the oldest ball python known to have laid eggs.