The opening shots of the 2016 United States presidential race were fired on Monday US time (Feb 2, Singapore time) at the Iowa caucuses.

After months of debates and polls, citizens in the mid-west state put some real numbers on the chances candidates have at winning their party's nomination.

There are many more caucuses and primaries in the lead-up to the Nov 8 election, but results in Iowa are an early signal of how the country as a whole will respond to the candidates. Here's more about the winning three:

TED CRUZ, 45

1. How he fared

Of the 12 Republican candidates, Republican Ted Cruz was the surprise winner, upsetting billionaire Donald Trump. The Texas Senator led Mr Trump by 28 per cent to 24 per cent, and Senator Marco Rubio of Florida finished close behind Mr Trump with 23 per cent.

2. Where he grew up

There have been some legal challenges filed against Mr Cruz, claiming that he is not a "natural-born American" and thus not eligible for the presidency. Mr Rafael Edward "Ted" Cruz was born in Canada in 1970. His mother is Irish-American, and his father moved from Cuba to the US in the 1950s. Mr Cruz held dual US and Canadian citizenship till 2014.

But he only lived in Canada till age four, and has spent most of his growing up years in Houston, Texas. There is no doubt he is an American citizen.

3. Schooling years

Mr Cruz knew from an early age that he was interested in law and politics. He was a champion debater at Princeton and went on to Harvard Law School. He was a brilliant student who had clear conservative leanings early on.

"He came to class with his right hand in the air and he kept it in the air for the whole semester," a professor who taught Mr Cruz at Harvard told The New Yorker in 2014.

4. Political career

After a successful legal career as an appellate lawyer, he was policy adviser during Mr George W. Bush's 2000 presidential campaign. In 2012, he was elected to the US Senate with the support of the Tea Party.

He has built his career in Washington on brinksmanship - famously orchestrating a 2013 government shut down in protest against national healthcare insurance programme Obamacare.

5. Family

He met his wife Heidi Cruz, 43, while they were both working for the Bush campaign. She has taken a year off from her job at Goldman Sachs to raise funds and campaign for her husband. They have two daughters, seven-year-old Caroline and four-year-old Catherine.

6. What you may not know about him

Last year, an article in the Washington Post was headlined "A lot of people just don't like Ted Cruz. How come that's okay with him?"

Many people who have been to school or worked with Mr Cruz have said how unpopular he was with his peers. He is regarded as a brilliant strategist with a photographic memory, but some described him as abrasive. He was reportedly sidelined by the Bush administration for this reason, and admitted himself that he was not someone you would "grab a beer with".

HILLARY CLINTON, 68

1. How she fared

The Democratic race was tight as Mrs Clinton declared victory while her opponent Vermont Senator Bernie Sanders said the result was a virtual tie. Mrs Clinton took 49.8 per cent of the votes, against 49.6 for Senator Sanders.

2. Where she grew up

Born Hillary Diane Rodham in 1947, the former first lady and secretary of state grew up in Chicago, Illinois. Her father, a fabric store owner and her mother, a housewife, were both Republican. Mrs Clinton became a Democrat in 1968.

3. Schooling years

She was Wellesley College's first student commencement speaker and one of 27 women in her graduating class of about 200 at Yale Law School. She and future husband Bill Clinton had their first date at the Yale Art Museum, he wrote in his memoirs.

4. Political career

Mrs Clinton was the only woman on the staff of the congressional committee that investigated Watergate. The scandal brought down former president Richard Nixon, who resigned in 1974.

Her husband was governor of Arkansas for 12 years before serving as US president from 1992 to 2001. She was the first first lady to be elected a senator in 2000, and served as US secretary of state from 2009 to 2013.

5. Family

In 2014, Mrs Clinton became a grandmother. Her only daughter, Chelsea, gave birth to a girl, Charlotte Clinton Mezvinsky.

6. What you may not know about her

Mrs Clinton's name is spelt with two 'l's because she is named after mountaineer Sir Edmund Hillary. In 1995, she travelled to Nepal and met the man who conquered Mount Everest and gave her her name.

BERNIE SANDERS, 74

1. How he fared

For Mr Bernie Sanders, a near-tie with Mrs Clinton was beyond his own expectations and a boost to his campaign. The Iowa result has cast some doubt on a nomination that appeared to be all but Mrs Clinton's.

2. Where he grew up

Mr Bernard "Bernie" Sanders was born to a lower-middle class Jewish family in 1941 in Brooklyn, New York. His father, a paint salesman, was a Polish immigrant while his mother was born in New York to Jewish immigrant parents from Poland and Russia.

3. Schooling years

Unlike Mrs Clinton and Mr Cruz, he was far more interested in political activism than academics at school. In high school, he ran on the track team. He went to Brooklyn College and the University of Chicago where he studied political science, and was involved in the civil rights movement at university.

4. Political career

The young Mr Sanders could hardly make rent and once worked as a carpenter, freelance writer and film-maker. He launched his political career in 1981 as the mayor of Burlington, the largest city in Vermont.

While he is competing for the Democratic ticket, he is an independent politician who is a self-proclaimed socialist, and seen as outside of the establishment. He became a congressman in 1990 and won a Senate seat in 2006.

5. Family

Mr Sanders has not talked much about his personal life. He was married to first wife Deborah Shiling from 1964 to 1966 and had a son, Levi Sanders, with his girlfriend Susan Campbell Mott in 1969.

He married Mrs Jane O'Meara Sanders in 1988 and has three stepchildren with her.

6. What you may not know about him

Mr Sanders once recorded a folk music album. In 1987, while he was mayor of Burlington, he recorded five folk songs with 30 Vermont artists.