Malaysia’s last surviving male Sumatran rhino has died, wildlife officials have said, leaving behind only one female in the country and pushing the critically endangered species closer to extinction.

Once found as far away as eastern India and throughout Malaysia, the Sumatran rhino has been almost wiped out, according to the World Wildlife Fund (WWF).

The smallest species of rhinoceros was declared extinct in the wild in Malaysia in 2015. Iman, a female captured in 2014, is the only surviving member of the subspecies left in the country. Wildlife experts estimate that only about 30 to 80 Sumatran rhinos remain in the world, mostly on the Indonesian island of Sumatra and on the Indonesian side of Borneo.

Augustine Tuuga, the Sabah Wildlife Department director, said the Malaysian male, Tam, had lived in a nature reserve on Borneo island. The cause of the animal’s death was not immediately clear, but previous media reports suggested he was suffering from kidney and liver problems.

Tam’s death puts pressure on the ongoing efforts of conservationists hoping to use in vitro fertilisation to create offspring from Iman and an Indonesian male. Tuuga said there were problems with Iman’s uterus and that she was incapable of becoming pregnant, but was still able to produce eggs. “We just have to look after the last remaining rhino. That’s all we can do, and try – if possible – to work with Indonesia,” he said.