With his wide mouth planted squarely on the dusty floor, it is almost as if Sudan understands his plight. A photograph of the last male northern white rhinoceros has gone viral after being posted on Twitter in order to illustrate the meaning of extinction.

Sudan is the only surviving male of the species and lives with the last two females on a wildlife conservancy in Kenya as scientists race to develop IVF techniques that might keep their lineage alive.

His image was posted on Twitter by Daniel Schneider, a biologist from Boston, who frequently highlights endangered species.

The message has been retweeted more than 39,000 times.

Sudan was already the most famous rhino in the world.

He was featured in a BBC documentary, Sudan: The Last of the Rhinos, which was broadcast in June.