Travelers to Israel know of the omni-presence of cats.
What's relatively new is the increase in the number of dogs. Tel Aviv is apparently the world's most dog-friendly city.
One answer I heard is that there's a perception that Arabs fear dogs and that during the most recent spate of "lone wolf" attacks about a year ago, there was an increase in dog ownership (as well as gun permits).
Another theory I heard was that the increased dog ownership is actually a proxy for increased wealth.
As my friend Gil said, "when you have food and housing security, you feel like you can get a dog."