Why does json.Unmarshal work with reference but not pointer?

Question

This example from the json.Unmarshal docs (slightly modified for simplicity to use Animal instead of []Animal) works, no errors:

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Answer 1

Because your pointer is nil.

If you initialize it it works: http://play.golang.org/p/zprmV0O1fG

var animals *Animal = &Animal{}

Also, it can be spelled either way (consistency in a single doc would be nice, though): http://en.wikipedia.org/wiki/Marshalling_(computer_science)