Alder moth caterpillar

This is the first time I've encountered this creature. This caterpillar is the larva of a nocturnal papillon Alder moth. (Latin name: Acronicta alni). The adult caterpillar looks quite spectacular! NB: In the early stages of development, these caterpillars look like less fancy: black in front and white behind. The larvae feed on alder and oak leaves, also may consume aspen, hazel, and birch leaves. There's quite a lot of alder trees growing at my land and in neighboring areas -- I have no doubt these moths inhabit this area in considerable numbers.

It's possible that I've encountered and photographed these butterflies before, but their gray, unremarkable, camouflaging coloration prevented me from identifying them. But such a caterpillar is truly unmistakable and unforgettable! I don't think the caterpillar is dangerous or poisonous, but its coloring is deceptively convincing and will undoubtedly warn and deter predators. Incidentally, I'll note for the record: of all the recently seen specimens, this was the fastest and most tireless one. The caterpillar was constantly moving quickly and trying to escape; without the use of a refrigerator and additional cooling, I couldn't get it to calmly pose for me in place...