Sudan is the last of his kind. He's a male northern white rhino, the only one in the world known to still be living. He has two female companions, making the trio the final outpost of this critically endangered white rhinoceros subspecies. 

Sudan is also 45 years old, which is pretty elderly for a rhino, and he's having some health problems.

The nonprofit Ol Pejeta Conservancy in Kenya cares for Sudan and his companions. In February, the conservancy reported Sudan had developed a serious age-related infection in his back right leg and said "his future is not looking bright."

But there is some hope for Sudan. Ol Pejeta reported improvements in the rhino's mobility and appetite in recent days.

Sudan has been unable to breed with his companions, in part due to the advanced age of all three rhinos. Sudan's situation came to the world's attention last year when he joined Tinder in search of an eligible mate and to raise funds for research into breeding methods.  

The northern white rhino is thought to be extinct in the wild due to poaching and the effects of civil war on the animal's natural habitat in Africa. The rhinos at Ol Pejeta are protected with around-the-clock security. 

White rhinos can live up to 50 years, according to the International Rhino Foundation conservation group. Sudan is already pushing the lifespan limit for his species, but he will continue to receive intensive veterinary care in hopes of keeping him comfortable and prolonging his role as a living reminder of the human impact on vulnerable species.