Two polls published Tuesday show a clear gap at the top of the Democratic presidential race, with only the four leading candidates achieving double digits. But Sen. Elizabeth Warren's numbers slipped in both.

By the numbers: Former Vice President Joe Biden has retaken the lead in the latest Quinnipiac University poll, with 24% of Democratic and independent voters who lean Democratic backing him. South Bend Mayor Pete Buttigieg jumped 6 points to snatch second place (16%). Warren's numbers fell 50% over the past month to receive 14% support. Sen. Bernie Sanders polled at 13%.

Sanders stormed to the lead in the latest New Hampshire Emerson College poll, with the support of 26% voters ahead of the first-in-the-nation primary.

Buttigieg placed second with 22% of those polled backing him. Warren and Biden both achieved 14%.

Why it matters: The polls are a blow for Warren, who enjoyed a surge of support to lead several polls in September and October. However, she's faced criticism since introducing her "Medicare for All" plan from progressives and moderate Democrats.

Between the lines: Axios' Neal Rothschild noted that NewsWhip data provided exclusively to Axios this month shows Warren has taken a "beating on social media after claiming middle class Americans won’t pay higher taxes to fund health care coverage fully paid for by taxpayers."

The big picture: In the New Hampshire Emerson College poll, conducted Nov. 22–26, the sample consisted of 1,184 registered voters. The margin of error was ±2.8 percentage points.

Quinnipiac University surveyed 1,355 voters nationwide with a margin of error of ±3.2 percentage points. It includes 574 Democratic voters and independent voters who lean Democratic with a margin of error of ±4.9 percentage points.

Read the full Quinnipiac University poll:

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Editor's note: This piece has been corrected to show that Pete Buttigieg jumped 6 points in the Quinnipiac University poll (not 16).