Do you mean the blue tinge on the bits where the sky meets the scenery? If so that would be chromatic aberration (purple fringing) and unless they start putting some bigger optics on these phones (i.e. turn them into cameras) it's never going to be great, I've got a £350 lens that still gets has a bit of purple fringing in a really high contrast shot, such as a very bright day with trees for example.
As the pixel count goes up the various problems will only get worse, once they find a balance between a good optic, sensor and a sensible amount of pixels (I'm guessing 2MP) they can work on quality, but as with the real camera world it all seems to be about the megapixel race.
For what it's worth those zoo shots are fantastic though, most probably because they are fairly easy for the camera as there are not bright skies involved and/or they are pointing away from the sun.