All that glitters is not gold... sometimes it's otter poop

River otter
Muller Field Station, 9/12
Photo credit: FLCC student field study

I am the Co-PI on a grant from NSF to increase undergraduate research at the community college level. Our approach is to develop some sort of intervention at the freshmen level to introduce students to research (case studies, for example) and actual participation in research projects in second-year classes. I have two classes with a research component: Black Bear Management (read about their exploits here) and Wetland Mammals. Among other things, the grant has allowed us to partner with other institutions and individuals. That is how we became involved with a river otter research project being conducted at SUNY-ESF. Elaina Burns, ESF Master's degree candidate and FLCC alum, is attempting to survey the population of river otters in the Finger Lakes Region of NY. Her work centers mostly around otter latrine sites where she is collecting scat samples for DNA analysis and setting camera traps for visitation rate and group size data. My interest in the project goes beyond the short-term involvement of my current students to the long-term mimicking of her protocols on a much smaller scale to monitor the otter population in our part of the Finger Lakes.

One of the great things about research is that it often promotes MORE research. As the river otter scat samples are being processed in the Biotechnology Lab at FLCC, student Micheal McIntyre wondered if we were doing all we could to preserve the DNA in the samples after collection. After a literature search of other studies, Micheal proposed that we collect some scat this winter (our off-season) and see if there was a difference in success rates of DNA extraction among three different collection protocols. Thus, a mini-research project was born! "Mini", but with some very practical applications to our work and the work of others. It is expensive and/or time-consuming to collect otter scat. We cannot afford to squander these samples (waste the "waste" if you prefer) so knowing how to store the samples to preserve any otter DNA present is very helpful.

River otter tracks
(Hi Tor WMA, 1/13)

One of the Conservation Technicians at FLCC (Sasha Mackenzie) had discovered an active otter latrine site in December. But the winter had arrived since then and we had about two feet of snow on the ground and the pond would surely be frozen over. What if the otters had moved on? On January 2nd, she and I strapped on snowshoes and went to visit in order to determine if it was still active and how feasible it would be to collect scat from that location. We arrived to find not only an active otter latrine, but a real live otter to boot! We set up a camera trap and headed back to the vehicle, discussing the logistics of collecting the fresh scat samples Micheal would need for his study.

On January 12th, I revisited the site. Will (a current student at FLCC) and Alyssa (FLCC alum) made the trek as well. It was an enjoyable day. The weather was nice (despite the rain) and the distractions were many. We had lots of different dog tracks to inspect. We followed a fisher for a while. There were insects about. We approached the pond in stealth mode, hoping to see an otter. We were not disappointed. Three otters were making the most of a small hole in the ice. Up and down and over and around the otters writhed and tumbled in the hole.

River otter latrine
(Hi Tor WMA, 1/13)

The show was short and we set to work. We visited what I would call the secondary latrine site first. I introduced Will to the wonderful world of otter scat. Note the hole that the otters had been using to access the shore. There were a few scats present at that level, but the real show was atop the mound. The otters were climbing the small stump and leaving scat as high as possible. You can even make out a very steep slide (just to the left of the center of the mound) where they would make their way back down.

River otter scat
(Hi Tor WMA, 1/13)

We found a fresh looking scat with some associated jelly and Will took out the collecting gear (Jelly is produced in the otter's intestine and is thought to help lubricate the system to help with the sharp bones and scales).









The jelly is preferred over scat in DNA studies for the simple reason that the jelly is 100% otter whereas the scat is mostly DNA from what the otter consumed with some otter cells mixed in.

Collecting otter jelly
(Hi Tor WMA, 1/13)

Sample tubes

First order of business is to glove up. We do not wish to contaminate the DNA, but we also do not wish to degrade the sample in any way and humans carry chemicals that are designed to do just that. Will opened the first collection tube and used the attached scoop to collect the jelly. A third of the sample goes into 70% ethanol, another third goes into a concoction called DET buffer and the remaining third is stored in no media at all as a control. All vials are then frozen until they are processed in the lab. From there, we headed to the main latrine. I was anxious to see if we had any photos on the Cuddeback Attack camera trap.

Beaver girdled this tree
(Hi Tor WMA, 1/13)

The otters appear to be using an abandoned beaver lodge as their home for the winter. I am somewhat familiar with this location and know there have not been beaver here for many years. Beaver leave their mark on the landscape for some time. It is common for otters to use beaver lodges as their own. Sometimes they have to "evict" the current owners.






Here is the view from the camera trap. You can see the beaver lodge in the foreground and the pond beyond. Even from this distance, you can see the area near the shore is COVERED in scat.

River otter latrine site
(Hi Tor WMA, 1/13)

The camera trap indicated seven photos had been taken. I was hoping for more, but we had so much snow melt that I believe the camera was now too high to be triggered! I changed SD cards and we proceeded cautiously out to the latrine site. It was hard to tell exactly where it was safe to step.This is literally the largest river otter latrine I have ever seen.

We found more jelly as well. Jelly can come in many colors including clear, yellow, green and the putrid color you see here :)

River otter scat and jelly
(Hi Tor WMA, 1/13)

The protocol allows for collecting only fresh scat samples so we have the best chances of recovering DNA that  can be analyzed in the lab. As the scats get older, the DNA degrades. This study calls for the latrines to be visited daily until we have enough scat samples. A different team was to visit the next day. How would they distinguish fresh scats from all of these older ones? With all the rain, EVERY scat looked fresh. Answer: glitter. Glitter is ideal. It is cheap, non-toxic and comes in a shaker. Will was the head glitterizer...

Before:

After:

It took a LOT of glitter....

Adding glitter to otter scat
(Hi Tor WMA, 1/13)

On our way out, I turned the camera trap back on. As we walked back, I found my thoughts straying to the SD card in my jacket pocket. It had been a long time since I got a good story out of a camera trap. Did I get anything good at this set? Yes. Yes, I did.

A pair of coyotes had visited the site.

Eastern coyotes
(Hi Tor WMA, 1/13)

But the prize were my two otter photos. One showed three otters together:

River otters
(Hi Tor WMA, 1/13)

Notice the coloration of the throat. River otters almost always show that lighter underside to the face and chest.

The other shows a fascinating aspect of river otter travel. Otters are known to slide on snow. In fact, they are known to slide downhill, on level ground and even UPhill. I wanted to get a photograph of an otter slide to add to my classroom lecture on this species. I know I can pull a photo off the internet, but I pride myself on using as many of my own photos as possible. So imagine my delight when I got a photo of the otters in action. Check out this tandem slide!

River otters sliding
(Hi Tor WMA, 1/13)

Not one but two otters sliding side by side. Amazing. And look at the older otter slide on the left of the photo. This is great! A few minutes later and there would have been enough light to have this in color. How am I sure these are otters and not the similar looking mink? Well, I was there at the site and know these animals are far too big to be mink. Secondly, I can see the light throat mentioned above.

In my Wetland Mammal class last fall, one student group had great success with capturing otters on their camera trap. The camera itself was jostled so everything is at an odd avant-garde angle.

First, an otter. Remember, something caused the camera to tilt. Look how sleek this guy looks!

River otter
(Muller Field Station, 9/12)
Photo credit: Student field study

Now a mink. The camera angle has not changed. Look how much smaller the mink is. Note the lack of a light patch on the throat and chest.

Mink
(Muller Field Station, 9/12)
Photo credit: Student field study

I will keep you updated on these projects as they progress. For now though, remember the lesson for today: "All that glitters is not gold..."

Check out Alyssa's blog entry on this encounter at Nature in a Nutshell.