Xiongsen is the world’s biggest battery farm for rare animals. Located just outside the southern Chinese city of Guilin, it is smaller than Regent’s Park but holds 1,300 tigers – almost as many as the whole of India – as well as hundreds of bears, lions and birds. The stock is worth hundreds of millions of dollars in China, where consumers pay high prices for remedies, tonics and aphrodisiacs made from rare species. But until now the park has only been able to bank its assets in cold storage because of a ban on tiger products.