I ask this question with a back story, first let me say, I don't mean the growl that can be heard at the beginning of a bugle, I mean a deep loud growl like nothing I have ever heard before (nor my father).
The back story is with a successful spike hunt without pictures (sorry).
Anyway, this last year, my father and I made our second ever elk hunting trip, and we were in the Naneum area. The very first day of the season, we got up very early and hiked into a decent looking spot to sit for the breaking of daylight. On the way in, we got semi turned around and had to back track to get back on the trail we wanted, and also spooked a couple of elk, we heard them running off through the brush. This was still a good distance from where we wanted to sit, so we kept moving in hoping we hadn't busted our spot. We got there, and sat for a few hours without seeing or hearing anything. We hiked around the area a bit after sitting for that time to warm up a little and try to see if we could move into some animals, again no luck.
We headed back to camp and broke for lunch after seeing nothing all morning. After lunch, we drove out to a closed gate road and hiked a couple of miles out on the road and glassed a decently open hillside that we ran across, and sure enough, we saw an elk sitting way up on top of the hill under a tree. We spotted it while it was moving, and I was positive that it was a bull and pretty sure it was a small spike. Well, we didn't get to look at it long and hard, as it moved out of sight basically right away. It kind of looked like it might have moved in the downhill direction towards us, so we watched the hillside for a while. We didn't see it come back into sight for about 15 minutes, so I decided to move uphill to our right and see if gaining elevation might give me a bit of a different angle to look at. While I was doing this, I spotted a cow about 100 yards below where we had spotted the bull, so I stopped and watched her for a bit. After a few minutes, another cow moved out of the brush and into view, so I continued to watch. A total of 5 cows came out, but we didn't see a bull, now I was very positive that the first one we saw was a bull, so I moved uphill a bit more. Not long after I moved uphill a bit, the cows moved up and over the hill in front of us, never seeing a bull.
At this point, my father and I decided to drive up the road the gated road branched off of and see if we couldn't maybe get on the uphill side in the direction the elk had moved and maybe get another look at them. Well, as we drove up, we kept seeing vehicles parked at various pullouts in pretty large numbers, which discouraged us from our idea of getting ahead of the elk, but made us think that with that much pressure on top, the animals might turn back around and move back towards where we saw them. So, we drove back down to the gated road, and no one was parked there, so we got back out, grabbed our spotting scope and decided to hike back out to where we were before and just watch the hillside until dark.
Sure enough, as soon as we get to the little bluff we were at when we first spotted animals, we saw 6 elk much closer to our position on the hillside in front of us. Looking them over, there is a lighter colored one in the middle of the group, that we suspect to be a bull. Bringing up my binoculars, I can immediately see that it is a bull, and it is a spike. Oh, lucky day is going through my mind, only the second year, and the first day to boot and we have a legal animal in our sights. At this point, we figure the elk to be 400-500 yards away, not the greatest shot, but the wind is not in our favor scent wise, and the terrain is pretty open in front of us. So, we decide to wait for the spike to break apart from the cows a bit and take the shot. Now, I had never shot at an elk, so I just let my father go ahead and take the shot, I wasn't too particular, as we have a deal that we split what we get, so I knew if he took it, I was getting at least half an elk this season. Well, we had a perfect stump in front of us for a rest, and my father got down and sighted in on the elk with his 300WSM....Boom!...I can't see where the shot hits, and the elk do nothing but turn their heads to look behind them....Boom!...again nothing. After 4 shots, my father hasn't hit the elk, but he realises, he can't adjust his scope...it had moved somehow during the drive to camp. So my father says "why don't you get down here and shoot him!" and I reply "I am just waiting for you to get out of the way!!"
My father moves, and I set down and rest on the stump with my Browning 7mm Rem Mag. I find the spike, and adjust high due to the distance and the elk being a bit up hill from us. I take a deep breath and squeeze the trigger...Boom!... and the elk jumps, I had hit him! He takes a few steps, but stays on his feet, but stops (thank goodness here) So, I sight in on him again and Boom!, and he drops. Now the hill they were on is very steep, and he starts to roll downhill, stopping behind a tree, I see him kick a couple times, enough to loose himself from behind the tree and continue rolling downhill. At this point, the hand shaking and smiles go around between the 2 of us, but we do acknowledge that it is about 4:00 PM and we don't have a lot of time until dark. So, we mark a couple of large rock outcropping landmarks to direct us to where the elk went down and we start out up the hill (very steep and rigorous hike). We get up to about the level we think the spike was at and start heading horizontally across the hillside toward where we thought he went down, when I hear some movement ahead of us, and look up in time to see an elk butt taking off behind a tree in front of us. At this point I am thinking "oh crap...he is running and it is nearly dark." so, we cross a little draw and get to the tree the elk got up from underneath, to find no blood, nothing, just a bed. While I am searching for blood thinking "I have no trail to follow and he isn't leaving much of a footprint trail to follow with all of the tracks ALL OVER this hillside

" when my father says "what is that over there?" I look up and take a few steps toward my father and see this tan hump sticking up just over the knoll in front of us. A couple of steps more proves it to be the spike, which had stopped rolling downhill when he hit an old stump.
It had taken us about 45 minutes to get to him, so we got to him asap and noticed that he hadn't fully shed his velvet, which seemed kind of odd, but oh well, he was a legal spike! I started straight in to gutting him, so that we could start the job of dragging this very large animal back to the vehicle and use as much of the natural light we had left to get as far as we could. Now, as I mentioned earlier, the hillside was quite steep, so as soon as we got him gutted, we pulled him out from behind the stump and let him roll downhill, we didn't want to waste energy trying to hold him back, and didn't want to get tripped up and end up underneath him as he was moving downhill either. Well, we knew the gated road was below us downhill, so we just kept heading in that direction wondering when we were going to run into it. After we got past the steep part of the hill, we started the dragging, which wasn't too bad since it was still a slight downhill, but the path in front of us was full of sticks and brush left over from a logging outfit a few years earlier, so we kept having to drag him over all sorts of sticks and stuff that made the work that much more difficult.
Well, it was starting to get quite dark, and we hadn't run into the road yet, so we started discussing our options. Well, we didn't expect to see anything (Stupid, Stupid, STUPID us), so we had left our pack frames, water, and rope back in the truck. So, we decided, we would just keep dragging till we hit the truck, as we did each have flashlights in our pockets, me a mini mag, and my father a small LED flashlight (lifesaver here). We finally hit the road, and at this point, the work was getting very hard dragging a whole elk over pretty much level ground. Also, it was now pitch black out, and we knew we had a couple of miles of dragging on the road just to get to the truck, and some of that was going to be uphill. So, we took a breather and split the elk in half at the rib cage so that we could drag one half about 100 feet, and go back and get the other half and drag it back to the first half. In this way, we got regular short breathers on our walks back for the half behind us. Well, we hadn't been doing the road dragging very long when the elk started to chirp and bark around us, and they seemed to be keeping pace with us. Now, I had never heard elk chirping and barking in the wild, and it was kind of spooky to hear them, at what felt a pretty close distance, and keeping pace with us, but I knew that with elk in the area around us, there likely wasn't any predators too close. I was being purposefully loud the whole time, just so the elk didn't get too close, but they kept right up with us barking and chirping all the way.
Well, after a while, out of nowhere comes this loud deep growl like nothing my father or I had ever heard before. It didn't remind me of a bear, and nothing like a cougar, but I will be honest, it was very scary knowing that I didn't own a sidearm, and my gun was unloaded strapped over my back and I was dragging a fresh kill behind me with a sound like that that close to us. My father though did have a sidearm, so he pulled his .44 mag out and fired a round into the air just for good measure. We didn't hear another growl, and the elk were still there barking and chirping (even after the gunshot), so we kept on dragging one half at a time along the road.
Now, I used to be in very good shape, but I have let a desk job at a computer get the better of me unfortunately, and I was getting very tired and my grip was weakening pretty badly, but we kept dragging one piece at a time, knowing that we would eventually get to the truck. We finally got back to the truck, and loaded the 2 halves of elk into the back and headed for camp. At this time, it was 11:00 PM, so we had been dragging for a good 5 hours plus, so we decided we would just skin and hang the elk and worry about quartering and bagging it in the morning, it was already below freezing, so we weren't worried about bugs at night.
Well, we got back to camp, and skinned him out by lantern light and went in to crash, too tired for even a celebratory whisky. When we got up in the morning, we quartered and bagged the elk and then took a break until lunch, after which we headed out to see if we couldn't get REALLY lucky and find my father a spike.
Well, we didn't see anymore animals over the next 2 days, and it was getting fairly warm during the day, so we decided that half an elk is better than no elk and packed up camp and headed home. On the way home, we relived our success and questioned what the growl we heard might have been, at which point I said I thought it had to be a bull elk or something, otherwise why would the rest of the elk kept on chirping and barking so close to us and where the growl came from. My father said he didn't' think an elk could make any sound that sounded like that, and I couldn't argue it.
Anyway, I keep thinking about that sound, and I figured I would throw it out on the site here and see if anyone else had had a similar experience elk hunting, as in hearing a growl like nothing they had ever heard before. Also I figured it made a good story and I wanted to contribute it to the site, especially in the relative downtime to give fellow members something to read

I will say though, that since that incident, I have now purchased a sidearm for carrying while hunting so that when my rifle is indisposed or put out of the way, I can have something for carrying, and I will never leave my pack, rope, and water behind when I go out, even if I don't expect to see anything. I will also never forget that night.
Well, I should be going, hope you all enjoy the story, and maybe someone out there has some input or ideas on what we heard.
-Stout