Everyone knows that a Cow Says Moo. Cows are herd animals and have complex social structures. Cows are classifed as domestic bovine, typically of the species Bos taurus. This nomenclature also applies to other large mammals including cattle, moose, sea lions and whales. Mooing is one way that cows interact and how they express their emotions. They use different pitches of sound to express different emotions. They moo to: seek their herd mates, calf or mother; say they are hungry; call for a partner when they are wishing to mate; raise alarm to warn their friends and family of potential danger; show contentment; and express pain. Cattle, or cows (female) and bulls (male), are the most common type of large domesticated ungulates. Domestic cows are one of the most common farm animals around the world, and the English language has several words to describe these animals at various ages. A baby cow is called a calf. A female calf is sometimes called a heifer calf and a male a bull calf. A heifer is a female that has not had any offspring. The term usually refers to immature females; after giving birth to her first calf, however, a heifer becomes a cow. An adult male is known as a bull. Many male cattle are castrated to reduce their aggressive tendencies and make them more tractable. Young neutered males, which are primarily raised for beef, are called steers or bullocks, whereas adult neutered males, which are usually used for draft purposes, are known as oxen. A group of cows, cattle, or kine (an archaic term for more than one cow) constitutes a herd. English lacks a gender-neutral singular form, and so “cow” is used for both female individuals and all domestic bovines. Cattle are commonly raised as livestock for meat (beef or veal, see beef cattle), for milk (see dairy cattle), and for hides, which are used to make leather. They are used as riding animals and draft animals (oxen or bullocks, which pull carts, plows and other implements). Another product of cattle is their dung, which can be used to create manure or fuel. In some regions, such as parts of India, cattle have significant religious meaning. Cattle, mostly small breeds such as the Miniature Zebu, are also kept as pets.