The fate of northern white rhinos is now in the hands of science after efforts failed when zoo keepers were unable to successfully move four endangered rhinos from a zoo in the Czech Republic to Kenya in order to get them to produce a calf. 

Zoo keepers in Kenya said their one male with not be able to breed with the two female rhinos in a natural manner. The other male rhino died of unknown causes earlier this year, according to Minneapolis Star Tribune.

Richard Vigne, chief executive of the OI Pejeta Conservancy, where the rhinos have been living since 2009, said the experiment always had a small chance of working even if the animals managed to breed.

Scientific tactics like in vitro fertilization and the genetic process of de-extinction are now being considered to save the species. OI Pejeta Conversancy said artificial reproductive techniques "could provide the last chance of survival for the world's most endangered mammal."

Vigne said the one success to come out of the Czech-Kenya experiment is that the rhinos were moved from a zoo to Africa, and that they were able to prosper in the environment.

"The fact that they haven't bred is clearly a massive disappointment, but there are new technologies being invented all the time to rescue technically extinct species," he added.

The growing demand in Vietnam for rhino horns has led to over 3,000 rhinos getting killed by poachers in South Africa since 2010, contributing greatly to the species' endangerment, Star Tribune reported.

Despite the loss of the last six northern white rhinos, there is still hope for the animal, as there is still a large amount of white and black rhinos in the southern region of Africa, even though southern white rhinos can't live in Central Africa.

Vigne pointed towards studying genetic material as a way to save rhinos, as scientists are currently using this technique to bring back the passenger pigeon and dodo bird. The genetic material of northern white rhinos still exists, which could prevent the extinction of northern whites, something Vigne refers to as "a real indictment of the human race."

"We're all responsible for it, and to stand by and watch it happen ... I think would have been horribly wrong."