david shipman has been given special access to one of the last survivors. >> of the quiet lonely shufflef a giant animal facing extinction. one of the last five of a rhino. they have built up one of the largest collections from africa. this rhino no longer exists in the wild because gulf war and -- because the horn it is prized. they are not reproducing. the last was 15 years ago. there is a real risk that this species would join the others that human activity has wiped out. >> you can witness them dying out one by one. it is a really desperate situation. i do not want to witness these animals die out like this in a few coming years. >> the zoo has gone to extraordinary lengths to try to encourage more offspring. it is quite a task to waste a rhino into the air. repeated attempts of artificial insemination has come to nothing. the procedures have dangers. >> when you are close, you realize how difficult the technique is for assisted reproduction. in one operation, a righthino died. this may be the last chance. scientists are exploring all of the options at the research center in berlin.