I'm wondering now whether it's the difference between sight hounds and scent hounds?
Scent hounds are too busy tracking with their noses to take any notice of you, whereas sighthounds spot you and see you as prey.
When I was a kid my cousins used to have two greyhounds and they literally saw me as the rabbit. It was straight off the lead and 40mph towards me. Luckily I realised that standing still was the best option 