Afternoon howling

[Caroline]

Just wondered if anyone knows what different types of singing/howling barking signify? Our Greyhound boy seems to only do it in the afternoon after I've taken him out and given him a spot of lunch (we've set a camera up to see what he's up to whilst we're out at work).
He barks a couple of times then makes a moose like 'rowooo rowooo rowooo' sound then settles down. He may repeat this process a couple of times inbetween long periods of rest. It looks and sounds like he's calling and then listening for a reply. He doesn't look distressed as he isn't panting or pacing. He doesn't do it in the morning and has the radio on all day.
This is the start of his second week with us and he's settled in really well. Being new parents we're curious as to what makes him do this in the afternoon and if it's a sign of him being anxious or not.
Thanks in advance.

[Lisa]

You might want to be careful that it doesnt escalate. The noise you describe is what us Greyhound folks like to call a roo. The reason he is waiting for a response is he is waiting for you to respond. He is basically trying to locate his pack and calling them home.

[Caroline]

Thanks for your reply Lisa. He's doing it less frequently and for much shorter periods of time now and fortunatley we've never come back in when he's doing it but we will keep an eye on it.