One of the greatest things about my job as a field biologist is the chance to see amazing things happen in the natural world. I see fascinating stuff every day while out in the mountains, but some happenings are truly memorable. In the past, that has included seeing bears swimming in Sierran lakes, Clark's Nutcrackers eating tadpoles of the mountain yellow-legged frog, water shrews diving for food in alpine lakes, and a deer swimming in a lake to escape two coyotes intent on a late October meal. That strategy by deer of jumping into water to escape predators seems to be one that they use fairly regularly, but I've never seen other animals do the same. Until this week.
I was in the southern Sierra Nevada doing my usual things, this time paddling around a lake to measure its maximum water depth. On this spectacular day in the mountains, I was staring at the world around me while paddling to what looked to be the deepest spot. I slowly became aware of a squeaking sound coming from somewhere in the surrounding foxtail pine forest. As the sound got louder I looked more carefully into the forest's shade. Suddenly, out of nowhere came a pika running at full speed parallel to the lake shore, with a weasel close behind. The weasel was closing fast on its prey when the pika suddenly turned toward the lake and to my amazement dove in. It then swam furiously out into the lake but the weasel stayed on shore, staring at the pika and at me. Apparently realizing that the weasel was no longer in pursuit, the pika turned to swim parallel to shore and after a minute or so of that, headed to shore in earnest. I was sure the weasel would run along the shore and grab the pika as it approached land, but instead the weasel turned and ran off into the woods. As soon as it hit the shore, the pika did the same but in the opposite direction.
Swimming pikas?! Who knew?
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