Zookeepers in Prague on Thursday made a last-ditch effort to help Ginni, the lioness, get pregnant.
Her two male companions, all members of an endangered species of lion, could not get the job done.
So the zoo decided to resort to artificial insemination.
The big cats at this zoo in the Czech Republic are rare Asiatic lions.
Just 143 of them live in captivity and the gene pool is limited.
Natural mating is more likely to produce offspring, but a European expert in animal reproduction says Thursday’s procedure went well.
“Everything worked quite well. So the timing was perfect, that was the observation from the keepers,” said Thomas Hildebrand, an animal reproduction expert.
“That was all like we really desired it, and we are quite hopeful that this is a success.”