When our first bullmastiff, Jasper, was about 5, we were out hiking with him, our bloodhound Beau, and our neighbor's dogs, Chloe, an American Bulldog, and Max, a shepherd lab mix. There was snow on the trail and towards the latter part of the hike, a couple of the dogs feet started bleeding from the crusty snow. My husband started urging us all on down the trail, and kept telling us to "keep together" and "keep moving." I didn't really pick up on what was going on, but we all kept moving -- I was kind of falling behind the others, and Jasper was following behind me when suddenly I tripped and fell down flat on the trail. Jasper took one look at me laying there, and instantly whirled around and went FLYING back down the trail the way we came, and my husband very cryptically said "I thought so." I was confused and said "you thought what?" Then he explained to me why he had been telling us to keep together and keep moving -- Jasper had seemed uneasy and had kept watching the trail behind us, and my husband had suspected the blood the dogs were leaving on the trail had attracted one or more coyotes, and they had been following us, he also thought he saw one when he looked back one time -- and when Jasper saw me go down he instantly took matters into his own hands (paws) and went back to take care of the problem!! He was only gone a few minutes and we all proceeded as before, but I felt so much SAFER knowing Jasper was guarding us!