The days that most people consider to be good weather days for the zoo are not good days for photographing. The number of clouds in the sky and the amount of contrasty bad light are inversely proportional. There are a couple ways to work with it, though.
Look for spots where you can turn that overhead blasty floodlight of the sun into a targeted spot light. There’s a lot of cover around this sea lion habitat that can add a some control to the light.
Look for natural reflectors. The rock this sea lion is napping on is very white. There’s also a big white wall a bit to the right of frame. The little bit of fill light I’m getting on the shadowside is all thanks to those structures reflecting light backwards.
Focus on composition. No amount of pulling at that shadows slider in lightroom is going to turn this into attractive even lighting, so pick your subjects and compositions with intent. Turned 45 degrees to camera left, this shot would have been garbage. It would be harsh light over the entirety of the sea lion, all the background elements would have been just as harshly lit.45 degrees to camera right and I’d have been unable to expose properly without creating a massive white halo and introducing all kinds of flaring into the image.
Lastly, don’t be afraid to say no to the picture, and just enjoy the zoo. I’ll show up on days where the light is trash, it’s hot enough that the animals aren’t active, yadda yadda yadda. I’ll put the camera down, and just enjoy the zoo; it’s what it’s there for. If you do find a good spot, that camera is right at your hip anyway.
The Zootographer 