Courteney Cox, unable to find a homicidal maniac in a haystack in ”Scream 4.” (Gemma La Mana/AP)

“Rio” easily won the weekend box office with a haul of $40 million, while the fourth installment in the Ghostface saga made a mere $19.3 million. That’s the lowest opening weekend ever for a “Scream” sequel; the only film in the franchise to make a more meager debut was the first one, which opened with little fanfare and $6.3 million before evolving into a sleeper-slasher hit.

So why didn’t “Scream 4” sell more tickets? For a few reasons, actually.

1. You can’t beat animated animals. It’s spring break season, which means that the lure of the family film is even stronger than usual. That explains why “Rio” was No. 1 and last week’s top movie, “Hop,” was No. 3, with $11.2 million. It’s tough for the R-rated “Scream 4” to compete with that, even if it is aiming for the coveted and decidedly different young adult market.

2. The reviews were not stellar. We’ve established on past occasions that what film critics say often has no bearing on a movie’s financial success. But there are occasions when reviews do matter. One of those occasions is when potential ticket-buyers are on the fence about whether or not to invest in a film. After an 11-year hiatus from “Scream” fever, the 20- and 30-somethings who probably felt the strongest nostalgia pull toward the series clearly were on the fence. Even though the reviews were not uniformly atrocious, there were enough negative ones to knock those people off of that perch.

3. Wes Craven and Co. had other horror competition. “Insidious”lacked the same level of marketing that “Scream 4” possessed. But it’s possible that some scary-movie buffs may have opted to see it instead, given the positive word of mouth behind the indie effort. As Box Office Mojo notes, it’s entirely possible that “Insidious”— which has made nearly $36 million in two weeks of release, on a budget of $1.5 million— could end up outgrossing “Scream 4.”

4. No one cares about “Scream” anymore. Eleven years have passed since “Scream 3” arrived in theaters. After a decade-plus, it’s possible that the original fans of “Scream” have simply moved on, and the potential new fans — many of whom were in elementary school or younger when the Sidney Prescott pictures became a pop culture phenomenon — weren’t invested in the ongoing narrative enough to bother. The odds of the movie seeing a bump in business in the coming weeks also look unlikely; from a money-making perspective, it seems like “Scream 4” may have missed its moment.

Or has it? Is there some chance “Scream 4” could rebound and become the No. 1 movie next weekend, over offerings from Tyler Perry and Robert Pattinson? Vote in the poll below to weigh in.