Yes, Greyhounds need martingale collars (a.k.a. humane choke collars) because the width of their necks is larger than the width of their head. Therefore, they need the limited slip action of martingales to stop the dog from backing out of the collar.

They can be as simple as this nylon martingale (costs about 4$ and usually comes with the adopted dog):


To as fancy as this:


I forgot the exact name of these, but these are basic martingale collar/leash combos. They aren't as good as the above collars, but many Greyhound owners use these as well:


I personally don't use the above collar/leash combo if I'm going to a high-stress enviornment because I do believe Giselle can back out of those.

Some people also sell leather martingales:


It should be worthy to note that you'll most likely become a collar addict and end up with 10-12 collars for a single dog I forgot how many collars Giselle has but we're running at about 7-8+. I know Seqqy's dad has a BUTTload of collars. I shudder to think of that girl's wardrobe!

If you have any questions about Greyhounds you need answered, please don't hesitate to PM me or just post here!