"It's an attitude thing, it’s ingrained in you or it’s not."

Clohessy, Brennan, Quinlan, O’Connell, Leamy, O’Brien. All dogs of war.

The Ireland team that takes to the pitch on Saturday to face Scotland in their opening Guinness Six Nations match will have some world class operators.

The side will be named tomorrow and there will be speed and footwork in the backs, experience at half-back, powerful athletes, technically astute scrummagers and line-out operators in the pack.  

And not a single dog among them.

The list of former Ireland players above are just some of the men who could bite when needed. 

Sometimes they crossed a line but they had that "ingrained" rugby virtue that has all but disappeared from the national team.

Defining precisely what a 'dog' is can be a tricky task.

If you watch your rugby on the TV you might wonder what exactly the commentator is referring to when they say 'dark arts’, if you stand on the sidelines you can sense something about a player that has it, and if you’ve played with one you know exactly what it is.

Brian O'Driscoll was speaking at the launch of Guinness Six Nations experiences

For Brian O’Driscoll, it's "not about being a thug, trying to throw cheap shots, it’s about being ‘nasty’ and physically imposing."

The former Ireland captain played alongside all of the above mentioned players. He knows.

Immediately upon hearing the question, ‘is there a dog in the Ireland team?’ O’Driscoll’s ears prick up. It’s been on his mind.

He takes a moment to mentally peruse the current squad, and try as he might to shoehorn one of them into that canine bracket, it can’t be done.

"It’s something that I’ve talked to a couple of coaches about," O’Driscoll tells RTÉ Sport.

"People think there is less necessity because of [TV] cameras [but] a dog isn’t about being a thug, trying to throw cheap shots, it’s about being ‘nasty’ and physically imposing and that’s why I always loved playing with Sean O’Brien.

"That's why, whenever he was fit, I wanted to see him in the team, because he brought ferociousness to everything he did.

"At training, but in particular in games, I’ve never seen him taking a backwards step.

"I just wonder, do we have that level, in the best possible way, that 'thug’ within the team that you want to throw their weight around a little bit and set out a few markers.

"We don’t have it in the second row. We’ve two great athletes but I don’t think it exists.

"[There’s] a little bit in Tadhg Furlong and Cian [Healy] but not to the Sean O’Brien or Paul [O’Connell] or [Denis] Leamy [level].

"Seanie lived on the edge and he crossed it a few times but it was the ferociousness of everything he did."

O’Driscoll, who won 133 Ireland caps and played on four Lions tours, doesn’t claim that the day of the dog is over. Look at the World Cup finalists, South Africa and England, they are there. New Zealand have them, too. 

So why don’t Ireland?

For all the justified praise that the schools system and academies receive as they turn out a seemingly endless supply of physically impressive specimens, immaculately groomed and unfalteringly polite, where is that streak, the killer inside that must sometimes rise to the surface?

"It’s an attitude thing," the 41-year-old former Leinster centre continues, "it’s ingrained in you or it’s not. It’s a very hard component to develop

"I think it’s a really relevant point [about the current production line], I really do.

"It’s something that I’ve thought about. That’s why I loved having Leamy in the team as well.

"He was softly spoken and very quiet and went about his business... but he was an absolute animal!

"If he could he’d hurt you and it’s that, where you could get a shot and you’d really [feel it].

"It’s about playing on the line, not trying to play [dirty], this is a tough game that we play.

"At international level if you get an opportunity to set out a marker, don’t miss that chance.

"Sometimes rather than waiting for it to come, people have to go looking for it.

"That’s sometimes the difference between the real hardy boys and everybody else."

Follow Ireland v Scotland (kick-off 4.45pm) on Saturday via our live blog on RTE.ie/Sport and the News Now app or listen live on RTÉ Radio 1's Saturday Sport. Highlights on Against the Head, Monday at 8pm on RTÉ2 and RTÉ Player.