Nairobi: Researchers say the world's last male northern white rhinoceros, Sudan, has died after "age-related complications".

A statement from the Ol Pejeta Conservancy in Kenya says the 45-year-old rhino was euthanised on Monday after his condition "worsened significantly" and he was no longer able to stand.

The rhino had been part of an ambitious effort to save the subspecies from extinction with the help of the two surviving females.

Scientists hope Sudan's death won't be the end of the species. They plan to use southern white rhinos as surrogates to carry northern white rhino embryos created via IVF, using sperm from dead rhinos that is stored in Berlin and eggs extracted by surgery from the females at Ol Pejeta, according to the conservancy.