This paper examines attempts to naturalise the alpaca in the British Empire. In the nineteenth century Britain made concerted efforts to appropriate useful plants and animals and acclimatise them within its own colonies. The alpaca was a prime target for acclimatisers on account of its silken wool, which was manufactured into a range of luxury textiles. Its export was, however, banned by law in Peru and Bolivia, so the animals had to be smuggled out of the Andean states and shipped illegally to Britain and Australia. The paper studies the circuits of exchange that facilitated the transfer of alpacas from one continent to another and considers how British subjects in places as diverse as Bradford, Liverpool, Sydney and Arequipa promoted and benefited from the naturalisation scheme. It situates alpaca acclimatisation within a wider discourse of agricultural ‘improvement’, bio-piracy and imperial adventure.