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Saturday, February 4, 2012

A Natural History Mystery!

Earlier this week I visited FLCC's Muller Field Station as often mentioned in earlier posts. Some friends and I enjoyed an early morning hike along the channel path to enjoy nature and set some camera traps.

Muller Field Station - channel path 2/1/12

Along the way we found a very interesting type of mammal sign. Specifially a river otter latrine site! I took a Wetland Mammals course at the field station in the fall of 2010. We learned all about, ironically, mammals that live in wetlands: the beaver, river otter, mink, and muskrat.



If I refer to river otter as just 'otter', please keep that in mind :)

Otter make latrine sites for perhaps several reasons, but what is most commonly KNOWN is that it is an area that is heavily marked. The otters spend alot of their time in the water, but they're not totally aquatic. When they emerge from the water, they like an area adjacent to the water that is relatively vegetation-free. They return to this spot over and over to leave behind their scat and scent, which is that otter's calling card. The otters deposit scent by rolling, sliding, and scatting (is that a verb?!) again and again in the same location .

As you can see there's lots of space for otters a-rompin' and a-rollin' around. I set a camera trap on the site hoping for good results. Unfortunately, nothing to report. Granted the camera was only out for 4 days, but I was hoping we'd have a good chance of snapping the pic of an otter. This day we visited, we found an abundance of FRESH sign. We deemed it fresh because the scat looked succulent, moist, and had volume to it rather than it being washed out and flat looking.

Please know that this scat really isn't blue, it just looks it in the image because I was tweaking the colors. I'm all about imagery, so here's a good way to compare otter scat, if you've never seen it, to something that you can imagine: gray, cooked oatmeal. This day was very overcast, foggy, dreary, and the image came out very washed out, so that's why I tried to bring the color back. You can definetely see the texture in the scat which is a testament to the otter's diet: fish, crustaceans, amphibians, and any other macro-invertebrates they can get their jaws on. Lot's of scales, bones, shells, and exoskeletons.

And this lovely stuff is referred to by several names: puke pile, otter jelly, and my favorite: anal jelly.

THIS is the Natural History Mystery I mentioned in the title. There seems to be some debate over which end this slime comes from. In my opinion, after learning about this from my professor John who spent a week in British Columbia working with an otter biologist collecting this stuff, other naturalists who work with otter, reading TONS of literature and then finally, observing captive otters at The Wild Center in Tupper Lake, NY...I would say that this jelly is more anal than oral.

So now that I've isolated it to the hind region of the otter, there's another question: does it come from anal scent glands OR does it come from the anus? I think it comes from the anus, and here's why: in my Wetland Mammals class, we did a necropsy on a road-killed otter, and found a similar looking substance in its lower digestive tract. The theory is that it helps to aid the digestion of all that hard stuff and lubricating it through the digestive system.

There's alot of debate out there, but there is one thing we can assume about this otter jelly: it happens for a specific reason. There are no random happenings in nature.

Anyway, that's my brief blog entry on otters and scat and latrine sites. I am behind at least 2 entries, so hopefully I'll find time the rest of this weekend to get them out there before my school week starts again!

Myself and the 19lb road-killed river otter during Wetland Mammals!

2 comments:

  1. I had no idea about the anal jelly, nor did I ever know such slime existed. It does make perfect sense considering the abrasiveness of food in their diet. How brave of you to go where no blogger/biologist has gone before (lol).Otters are fun to observe and I've seen them in some pretty strange places before, several miles up large irrigation canals. Must be some good food in those ditches. I do believe they are opportunists and somewhat quick learners.

    ReplyDelete
    Replies
    1. The next time you are in otter-land, look for it and then...smell it! I know, gross, but it's an interesting smell. Sometimes, in a heavily scatted area, you can smell it in the air!

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~Alyssa