LOS ANGELES—Animated romp "Ice Age: Return of the Dinosaurs" shot to the top of the North American box office in its first week in theaters, but had to share the spot with "Transformers: Revenge of the Fallen," according to earnings estimates released Sunday.

The kid-friendly "Ice Age," featuring the voices of Queen Latifah and Dennis Leary as prehistoric animals who discover a lost jungle inhabited by dinosaurs, took $42.5 million in box office receipts over the three-day weekend.

That was exact same amount earned over that period by Michael Bay's "Transformers," according to box office tracker Exhibitor Relations.

The high-action, special-effects laden follow-up to 2007's first Transformers movie was panned by critics, but stormed straight to the top of the box office when it was released last week.

In third place was new release "Public Enemies," starring Johnny Depp as notorious US gangster John Dillinger, which pulled in $26.1 million in its first week.

Meanwhile, fourth place went to "The Proposal," a romantic comedy starring Sandra Bullock as a pushy boss who marries her assistant for a US visa, continued to draw audiences, taking in $12.8 million in its third week in theaters.

"The Hangover," a raucous comedy about the fallout from a Las Vegas bachelor party, came in fifth place with $10.4 million this week, bringing its four-week total to $204.2 million -- a massive gain on its $35-million budget.

Pixar's latest animated feature "Up," which tells the heartwarming story of a grumpy old man who finds adventure in Latin America, stayed strong into its sixth week in theaters for sixth place.

The hugely successful movie added another $6.5 million to the $264.9 million it has earned since its release.

In its second week in theaters "My Sister's Keeper," starring Cameron Diaz, slipped down in the rankings with box office receipts of $5.3 million, claiming the seventh spot.

"The Taking of Pelham 123," a remake of a classic 1974 movie about a subway hijacking, also fell one spot to eighth place, bringing in $2.5 million in its fourth week in theaters.

Rounding out the top ten were "Year One," a comedy about prehistoric hunter-gatherers, in the ninth spot, earning $2.1 million; and "Night at the Museum: Battle at the Smithsonian" for tenth.

The sequel to 2006's "Night at the Museum," which stars Ben Stiller and Amy Adams, also earned $2.1 million, bringing its seven-week earnings to $167.8 million.