Beware the Hedgehogs of Doom

Hello all! Sorry, it's been a while since I've popped my head up. But I'm still here!

My current travels/adventures throughout the British Isles are being related over at my usual blog, but I have conundrum I thought perhaps you all could help me with.

Now, I am not what you would call a huge fan of modern art. Usually I spend my time at modern art museums with raised eyebrows and a dubious expression, trying to avoid the hipsters and intelligentsia.

But a couple days ago I went to the Irish Museum of Modern Art in Dublin (I sort of accidentally walked past it and went, "why not?"). My full adventures therein can be found on my blog, but I want to share with you the strange sights that met me as I approached the entrance.

What is this? I thought, and paused to investigate further.

Can this be art? I thought (I occasionally get confused at modern art museums). But I looked high and low and nary a plaque with artist's name was to be found. There were definitely plaques at the other outdoor art pieces. Perhaps we are being warned against foxes. But then why the cat and the squirrel?

And there was this one, off to the right...

Caution: Hedgehogs. Maybe it's an Irish thing?

I stood there for a long time being confused. So perhaps you can help me, Gentle Readers: Are these signs...

a) Art. I was just too incompetent to find the plaque.

b) Warnings. I was lucky to have escaped the area with my life.

c) Neither. I have completely missed the purpose of these signs, which is _____.

Please help.