Viruses are intelligent. Not much, but their replication rate gives them a very rapid rate of evolutionary learning. Evolution is intelligent, but in a very different way from neural networks.

Bacteria and up are full of gene regulatory networks that are absolutely intelligent and share some features with neural networks. Bacteria learn, cooperate, signal, react, seek goals, and that's in addition to evolutionary learning which is also fast for them given their reproduction rate.

Evolution in nature isn't just zeroth order either. Look into a topic known as "the evolution of evolvability." Evolution does meta-parameter search on itself, more or less, and invents adaptations to improve its ability to adapt. Sexual reproduction is the most significant and largest example but there are others. There's environmentally dependent tuning of mutation rates, genome self-editing that we still don't fully understand (this is also how our immune system works), lots of epigenetic stuff we are still learning about, and so on.

If it's alive it's intelligent. All life is constantly learning.

Interesting, before Yudkowski was patient zero for AI doom he was a nanotechnology "grey goo" doomer. That was even more obviously absurd to me. Grey goo already exists. It's called biology, and it's been trying to maximize its footprint on Earth for 4.5 billion years. The miraculous instant "foom" grey goo thing is magical and likely violates conservation laws.