eloquent save () method does not work

When I try to use the save() method of eloquent-laravel 5.1, in the way it asks for documentation, the update is not done in the database.

This is how the documentation asks for it:

$flight = App\Flight::find(1);    
$flight->name = 'New Flight Name';    
$flight->save();

This is mine:

public function adotado($id) {         
        $animal = Animal::find($id); 
        if (Auth::user()->id == $animal->user_id) {
            $animal->ativo = 0;
            $animal->save();
            return redirect()->action('UserController@index');
        } else {
            return view('errors.restrito');
        }
    }

I checked with dd($animal) that data is being pulled normally from the database after find() , even the 'active' attribute is equal to 1. Within if , dd($animal->ativo) returns 0, ie up there the code is ok. The dd($animal->save()) also returns true and is normally redirected to the index, however, the update does not appear in db.

Any tips? Save me who can. Thankful.