TEL AVIV—After hours of training, Olly has learned to bound, tail wagging, toward his owners when called.
But the big shaggy pooch still sometimes growls in a back-off-pal warning when owner Itai Linzen touches him.
“It’s a bit like having a grumpy teenager,” said Mr. Linzen, who describes Olly as a mixed breed, part Dr. Jekyll, part Mr. Hyde.