What animal does yogurt come from ?

Yo' gurt is around yo belt line, Miss Lolita! :D

Running cows....................

It does not come directly from an animal but the closest is Homo sapiens (Humans). It is humans who make yoghurt. It requires bacteria which ferment milk. The bacteria involved are Lactobacillus delbrueckii bulgaricus and Streptococcus thermophilus.

Milk from Bos taurus (Cow: various breeds) is the most widely used but milk can be used from other mammals, including Bos grunniens (Domestic Yak), Bubalus bubalis (Water Buffalo), Camelus spp. (camels), Capra aegagrus hircus (Domestic Goat: various breeds), Equus ferus caballus (Domestic Horse: various breeds) and Ovis aries (Sheep: various breeds).

Not all yoghurts are made from mammalian milk and various plant milks are used.

the milk comes from a mammal, some bacteria turn the lactose into something else

It's usually spoiled cows milk. 

Yogurt doesn't come from a particular animal. In the US it is nearly always made using cow's milk. Did you know it's easy to make at home?