I went up into the mountain pass above home this morning to check out the moose. As it should be, the rut was on. Quickly located a bull with a really wide though not massive set of antlers. He had a couple of cows hanging around. All of them waiting for the mood to strike them. I had the opportunity to watch the bull create a wallow. They paw out a shallow depression in the ground then pee in it. Copious volume enough to basically make a puddle. Then the splash around in it with their feet and antlers and finally lay down in it. Then the cows come over and do the same. Some biologist theorize that pheromones in the bulls urine bring on estrous in the cow.
It is really interesting being around when this type of activity is going on. The moose can be extremely active and one typically has to shift shooting location several times, sometimes in quite a hurry
All shot with D4, 200-400mm VR, tripod
Here's a shot of the bull that really shows the breadth of his rack. This was immediately prior to one of those times that I had to move my gear...
And here's the cow laying in the bull's wallow.
And a bit closer, she was very patient. By this time the bull was also taking a nap. Which is why I was shooting the cow.