Made by Mott's, the name is a portmanteau of "clam" and "tomato". It is also referred to colloquially as "clamato juice". Clamato was produced in its current form beginning in 1966 by the Duffy-Mott company in Hamlin, New York, by two employees who wanted to create a Manhattan clam chowder style cocktail by combining tomato juice and clam broth with spices. Its history extends farther back, however, as a nearly identical drink was already present in a cookbook published 10 years earlier. They also named the new cocktail Mott's Clamato and secured the trademark for the new brand. The brand was owned by Cadbury-Schweppes after the company bought Mott's in 1982. It is now owned by the Dr Pepper Snapple Group after the business was spun off of Cadbury-Schweppes in 2008.
Clamato is used primarily as a mix for alcoholic beverages (an estimated 60% of sales in the US in 2008), and it is popular for this in both Canada and Mexico, but curiously much less so in the United States (outside of Canadian-American and Mexican-American communities). The Caesar is one of the top selling cocktails across Canada. A Canadian creation, the Caesar (or Bloody Caesar) was invented in 1969 to celebrate the opening of Marco's Italian restaurant at the Calgary Inn (now the Westin Calgary). Resident mixologist and food and beverage manager, Walter Chell, was commissioned to develop a new cocktail. He took inspiration from the flavours of Spaghetti Vongole (spaghetti with clams), and combined sweet (tomato juice), salty (clam nectar), sour (lime), spicy (Worcestershire sauce) and bitter (celery salt) into his new concoction. After naming it for the Roman emperor, legend has it that he served one to an Englishman who exclaimed: "That's a good bloody Caesar!"
Clamato is also added to beer in various beer cocktails (called Micheladas in Mexico). The most basic is known as a "beer 'n clam" or a "Red Eye" in Western Canada, which is simply the addition of Clamato to pale lagers. In 2001 Anheuser-Busch and Cadbury-Schweppes introduced a premixed version called the "Budweiser and Clamato Chelada" in the United States, which was panned by American beer critics. Adding more spices (similar to those in a Caesar) results in what is called sangre de cristo (blood of Christ) in Mexico.