Ocelots inhibit mob spawning nearby.

Neither hostile nor passive mobs spawn near ocelots.

I tested on a superflat world set to nighttime and covered in slabs.

I removed the slabs from a 20X20 area, spawned ocelots in holes and backed off 30 blocks, nothing spawned, nothing at all.

(There are only 25 ocelots so it's not the mob cap.)

Then I created a similar area without the ocelots and loads of mobs spawned immediately.

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I switched to daytime and used fill to place grass blocks and got the same result with passive mobs.