Larry the anaconda is shown blinking numerous times in the film. Snakes have no eyelids and cannot blink. He's also rather thin for an anaconda - they are heavy-bodied snakes - and has no trouble hearing the other characters when they talk to him, even though snakes have no external ears and are deaf to airborne sound.
It is stated the Wildebeest are carnivores, they're actually herbivores, as noted by Benny since "hooved animals don't hunt, they graze". This is because of their leader Kazar doesn't intend to be stuck at the bottom of the Food Chain.
If you watch very closely the edge of Larry's mouth during the first scene in the garbage truck drifting through New York, Larry opens his mouth, and there is a very visible bright line where the interior of his mouth should line up with his lips, but doesn't. It's a tear in the CG model, and should have been fixed before the character was animated. What you're viewing through the tear is the New York city scape.
After Benny has landed on the boat and Larry asks Samson if they're going to the wild, Larry pulls the throttle backwards. This would put the engines in reverse, yet in the film the boat continues going forwards and picks up speed.