Humans, it is often said, do not deserve dogs. But we do deserve better than "Strays."

The raucous, very definitely R-rated comedy follows a mutt-with-the-face-of-a-teddy-bear named Reggie (voiced by Will Ferrell) as he attempts to get back to his small-town home. He's in the city because his vile-but-Reggie-doesn't-know-it-because-dogs-love-everyone owner, Doug (Will Forte), dumped him in an alley. On his journey, Reggie has help from new, street-smart pals, whose voices are provided by Jamie Foxx, Isla Fisher and Randall Park.

Basically, "Strays" is "Homeward Bound" if it were dipped in acid and rolled around in lots and lots of dog poop (a scene where the pooches use it as a weapon is not for the squeamish).

That sounds like it could work, especially since Reggie returns Ferrell to "Elf" mode — playing a sweet, sunny character who just knows the world is an awesome place to be. When "Strays" sends Reggie to the city and shifts to dog-out-of-water mode, it remains entertaining to see our hero learn some new tricks from his worldlier friends.

Soon after, though, the movie becomes a dog. The friends' journey is repetitive and not very funny, with scene after scene consisting of a long shot of the pooches rambling through countryside while voice-over narration supplies stale jokes.

"Strays" wants to startle us with its tonal shifts — a sweet comedy that gets really profane — but its wild careening from sentimental to super-scuzzy makes it seem like the moviemakers lost track of what they were trying to do.

Part of that has to do with Doug, who may be the year's most odious movie character — and, yes, I have seen Harry S. Truman in "Oppenheimer." Eventually, Reggie figures out that Doug sucks and concocts a nasty revenge plot that "Strays" can only sell if we agree that pretty much no punishment is too harsh. Mission accomplished, I guess, but it makes the second half of "Strays" too sour and mean.

"Strays" is best when it leans into the actual behavior of dogs, whether it's them eagerly checking out each other's butts, rapidly twirling as they settle down for a nap or trying to sneak a drink of water from a blasting sprinkler.

That stuff is funny because it's so recognizable. But when the dogs become a violent gang, they — and we — deserve better.

'Strays'

** out of 4 stars

Rated: R for very strong language, drug use and (human) nudity.

Where: In theaters.