Bull Elk – A bull elk roaming through Mammoth Campground looking for members of his harem. He wasn’t in the best of moods and had me backing up. The elk mating season or rut as it is called extends from mid-September to well into October. During this time the bulls are much more aggressive towards one another and anyone or thing that may be perceived as a threat to their ability to breed. The more mature and larger bulls amass large harems of cow elk and keep them herded up so they can keep an eye on them while waiting for the proper time to mate. The keeping an eye on them includes watching for other bulls who would want to try to persuade one or more of the cows to leave the harem. This activity is fairly continuous throughout the daylight hours, but the bulls get little rest at night as they continue to keep watch. By the end of the rut, many successful bulls have lost over 25% of their body weight.