I'm using the same dataset, the 400k words 50 dimensions and I get the following results:
Horse : horses , dog , bull , riding , cat , pack , rides , camel , rode , breeders
frog: snake , ape , toad , monkey , spider , lizard , tarantula , cat , spiny , fern
lion: dragon , beast , unicorn , elephant , cat , bear , golden , peacock , rabbit , mermaid
I suspect the example on the site was made with one of the larger datasets, more words mean more chance for an obscure froggy reference and more vectors would mean a greater "resolution" of a search