This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Wednesday, November 27, 2013

How do elk swim? I think he walked over a bridge! His name is "Bruiser."

The Whidbey Island male elk
Image credit: Sasha Castaneda Whidbey News Times here
OK, it's definitely a fluid dynamics problem to figure out how a lone elk can land our elk-less island. Don't get ants in your pants, this is not post about how humans got to Easter Island or about genetic evolution. It's just a story about one lonesome male elk.
     I live on an island. There are three ways to get here: (1) drive over a bridge; (2) take a ferry; or (3) swim. It's 100% unlikely that this moose did not ride a ferry to our island, probably not quite so certain that he walked over the bridge.
     So, the common assumption in our local media is that he swam. But, if that's true, why didn't he swim back during rutting season? My hypothesis below is that he's actually not a good swimmer, that he didn't get here by swimming, and that he walked here. If that's true or even likely, we should shoo him back over the bridge so that he can not be so lonely! Having worked in Yellowstone National Park for many years, I can attest that (a) bull elk are not happy during mating season, and (b) that they will great distances for you-know-what.
     Here's the story: This handsome guy appeared on Whidbey Island in September of 2012, and is the only elk on Whidbey. He is probably a healthy bull in a mainland herd that no longer tolerated him. The common pattern would have been for him to find new land with a few accompanying females and start a new herd. But, here is now, alone on Whidbey. But, one year later during rutting season, he's still here?  According to the Washington Department of Fish and Wildlife, "the animal decided to stay put." But, is that realistic? If Bruiser could get back to the land of bountious females, would he actually "decide" to stay put? Not a chance in my experience with elk.
    So, what is going on? A healthy male elk lives about 15 years in the wild, and can weaight up to a half-ton. Like Bruiser in the photo, they can sport great racks (which everyone on Whidbey hopes will NOT become a target of illegal hunting--beware: there' a great island-watch on this guy....) How far would he have to swim?Elk are strong swimmers, aided by hollow hairs that keep them buoyant. During mating season, they "buggle" a mating noise that carries very long distances. You can see videos of them swimming, but if you Google "elk swim distances", there's no world record for an elk swim. They can definitely ford rivers, but is it an "easy swim" from the mainland to Whidbey as the Washington Department of Fish and Wildlife is saying?
   At best, this guy started in a herd in Skagit Bay on the mainland as Fish and Wildlife believes, he would have swum 4-5 miles direct from the Skagit tributaries to here. Not likely? At the very best, he'd have wandered up to Deception Pass (by himself, without his mistresses?) to Deception Pass where he had a narrow passage, but harrowing waters. If he got that far, why not walk across the bridge? On those autumnal days when there are few tourists, long dark nights, why would an elk near the bridge not just take a walk? It would certainly explain why he can't find his way home! What if Bruiser's females are just out of reach on the other side?
     It's clearly a fluid dynamics problem (Aside: traffic flow is a fluid dynamics problem) to reunite Bruiser with his herd! It's also an environmental problem because the Skagit Valley herd of 1700 elk have been driving Skagit Valley (mainland) farmers crazy over decades eating their crops. Fertile male elk are being culled from the herd by Federal, state, and tribal hunters, and they are authorized to kill 15 at the moment. Maybe Bruiser is a very clever elk.

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