Yaks are versatile animals, they produce milk and can be used for pulling and carrying. Their milk is used for ghee and butter.
In their natural habitat Yaks live above the snow line in winter, in temperatures as low as -40C. They walk following in each others footsteps. They burrow through the snow for food. In the spring they form larger herds moving onto the grazing pasture lands. They can also live in the tropics at +40C!
The male wild Yak can grow to over 2m high (6ft 8ins), and is the largest of all the cattle family. The domestic yak is smaller. They are very sure footed.
Yaks' horns can grow to almost a metre (3ft) long, but Yolanda only has one horn because she fell whilst having her feet trimmed and damaged it so severely that it had to be removed by the vet.
The yak is the wild and the domestic ox of the Tibetan Plateau in Asia.
Yaks are classified as Bos grunniens (domestic) because they grunt rather than moo. There are many different sorts of Yak, leading them to be also classified as Bos mutans.