Processionary moth caterpillars

It is the time of year when the weather is warming up, great news for those of us who hate the gloomy seasons, fantastic for plants, but also great for pretty well all those bugs and less desirable beasties!
I was fascinated to see the beautifully marked and hairy caterpillars of a processionary moth on a recent trip to France.  Literally hundreds of them wending their determined way across the drive of the house we were staying in.  Regimented in their manoeuvres, following a strict pattern of movement, almost as if held together by an invisible thread.  But not only do they have the potential to do serious damage to their host plants, if you have kids or pets you really should take care. 
I knew that the hairs on them are a dangerous irritant, especially to anyone who already has even a slight respiratory problem, and that they can cause a very unpleasant rash and even temporary blindness.  But I was horrified to read that many other animals, including dogs and cats are at risk : it is estimated that if a medium sized dog ate just three or four of them (and believe it or not, the caterpillars are said to have an appealing bitter-sweet taste!!) it would be likely to prove fatal.  And from what I gather it would also be a very unpleasant death.  So when you're on holiday or indeed if you spot their characteristic procession, do take care, and keep pets well away from them......a real case of , 'Look, but don't touch!!'