NANYUKI, Kenya (Reuters) - The world’s last male northern white rhino has died, the Kenyan conservancy taking care of it said, leaving only two females of its subspecies alive in the world, although scientists still hope to save it from extinction by in vitro fertilization.

Ol Pejeta Conservancy said it had made the decision with wildlife officials to put down the 45-year-old rhino, named Sudan on Monday, because of a rapid deterioration in his condition.

Sudan was being treated for age-related complications that had affected his muscles and bones and also gave him extensive skin wounds.

Sudan had previously lived at the Dver Kralove Zoo in the Czech Republic before being transported to Ol Pejeta Conservancy, about 250 km (155 miles) north of Nairobi, where he lived with the last two females of the same species, his 27-year-old daughter Najin and 17-year-old granddaughter Fatu.

The two female rhinos were quietly grazing at the conservancy on Tuesday, where staff mourned Sudan.

“It’s very sad to lose Sudan because it shows clearly the extent of human greed and what sort of impact humans beings can have on nature,” Samuel Mutisya, head of wildlife conservation at Ol Pejeta, told Reuters. “If we don’t take care of what we have, we will definitely continue to lose it, particularly lose other species that are currently endangered.”

Veterinarian Dr Stephen Ngulu said doctors recommended putting the aging rhino down because he was in severe pain, with no hope of treatment to alleviate it.

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“Sunday morning, he completely was unable to wake up. His left hind foot gave in completely, he was unable to support himself on it and he was not able to raise,” he said.

“We decided to evaluate the quality of life and advise stakeholders that this available option would be the better option: to alleviate pain, suffering.”

The rhino had spent two weeks in late February and early March lying in his pen due to discomfort from a deep wound on his right hind leg, the conservancy said. “The veterinary team from the Dvur Kralove Zoo, Ol Pejeta and Kenya Wildlife Service made the decision to euthanize him.”

After all attempts at getting Sudan to mate naturally failed, conservationists last year put him on dating app Tinder, hoping to raise enough money to pay for a $9 million fertility treatment.

Ol Pejeta said that staff had collected Sudan’s genetic material on Monday, which could be used in future to attempt reproduction of northern white rhinos. It said scientists were also seeking ways to perform in vitro fertilization.

“The only hope for the preservation of this subspecies now lies in developing in vitro fertilization techniques using eggs from the two remaining females, stored northern white rhino semen from males and surrogate southern white rhino females,” it said.

While there are thousand of southern white rhinos still roaming the plains of sub-Saharan Africa, decades of rampant poaching have drastically cut numbers of northern whites.

Poachers were able to sell northern white rhino horns for $50,000 per kilo, making them more valuable than gold.

Kenya had 20,000 rhinos in the 1970s, falling to 400 in the 1990s. It now has 650, almost all of which are black rhinos.