2012 One Dollar Animals of the Zoo-Orang-utan Coloured Printed Frosted Uncirculated Coin. Orang-utans are the largest tree-dwelling mammals in the world and share 97% of our DNA-making them one of our closet relatives. They are largely solitary and usually spend most of their time foraging in the highest canopies of the rain forest. Orang-utans build their nests out of leaves and branches each night in the tree tops and rarely come to the ground. Mintage unlimited. Please contact Adelaide Exchange Jewellers to find out more on this item.