I was pondering how you could have gotten so much light into the seal photo, while obviously keeping the shutter time so very short, when I realized the seal looked a bit..metal-ish But really, the other subjects must have been in quite a bit of motion too, hm, what ISOs did you use, if you don't mind me asking? I see no noise.
Nice shots here, I'm guessing you are using a super zoom?
I always have trouble getting good pictures at the zoo. The zoo here closes at 4pm, during which the sun is usually still out at full and I prefer to shoot the subject in shaded areas or when the sun has died down alittle. Shooting in the bright sun usually = blown out highlights or underexposed shots, but it seems you have done well controlling the lighting.