The weekend's other new wide release, Sony's urban drama "Freedomland" starring Samuel L. Jackson and Julianne Moore, opened a weak No. 7 with $7 million.
Hollywood had a healthy weekend, with the top-12 movies taking in $135.9 million, down a fraction from President's Day weekend last year.
Like the previous weekend, when "The Pink Panther" drew a strong family crowd while New Line's fright flick "Final Destination 3" grabbed horror fans, the two top movies scored well with different target audiences.
Parents and their children accounted for about two-thirds of movie-goers catching "Eight Below," while four-fifths of the audience for "Date Movie" was under 25.
"By programming two films that aren't chasing the same audience, you can really build a pretty good weekend for two movies at the same time," said Paul Dergarabedian, president of box-office tracker Exhibitor Relations.
"Eight Below" stars Paul Walker as a guide in Antarctica forced by a killer storm to leave his sled-dog team behind in the frozen wasteland, where the animals must band together to survive the winter.
"Date Movie" features Alyson Hannigan and Adam Campbell in a "Scary Movie"-type parody of such romantic comedies as "Hitch," "Meet the Fockers" and "The Wedding Planner."
While "Eight Below" drew solid reviews, "Date Movie" was not screened for critics beforehand, a sign the studio knows a film will get bad reviews.
"Young teens and early twenty-somethings, and that is who this is geared for, critics aren't necessarily quite in tune with that crowd," said Chris Aronson, general sales manager for "Date Movie" distributor 20th Century Fox.
Focus Features' "Brokeback Mountain," the favorite to win the best-picture Academy Award, continued to benefit from its Oscar buzz, taking in $3.8 million to lift its total to $72 million.
In limited release, the Russian fantasy thriller "Night Watch," a huge hit in its native country, opened strongly with $110,171 in three theaters, averaging a whopping $36,724 a cinema. By comparison, "Eight Below" played in 3,066 theaters and averaged $8,164, while "Date Movie" averaged $7,709 in 2,896 cinemas.
Distributor Fox Searchlight plans to expand "Night Watch" to about 150 theaters by March 3.
Estimated ticket sales for Friday through Monday at U.S. and Canadian theaters, according to Exhibitor Relations Co. Inc. Final figures will be released Tuesday.