River Otter Poo-pori of Facts

North American river otter (Lontra Canadensis): Photo-

Things You Didn't Know You Wanted to Know About River Otter Poop

Working with kids and the public it's hard to stay away from topics that make people go "eww" and get grossed out, because it grabs their attention. Now that's not to say that all of my program include poop, but there's something about scat or poo that helps people draw comparisons to themselves and find connection (if not humor) in nature's potty-paws.  I'm fortunate enough to live in an area with active population of river otters (Lontra canadensis). Most of you are probably familiar with the cute and fuzzy sea otters of the West Coast of the US, but the river otter of the Eastern seaboard and inland spaces is sleek and fun too. In this post I want to introduce you to ten facts about river otters and their poop, because poop plays a central role in a river otter's social life, and their social life centers around pooing.

A single otter poop is called a "spraint" like a "spraint" ankle. A place where there are multiple spraints is called a latrine.

Latrines are the social hubs for otters. When you're a medium sized mammal (3-4' long or smaller) then you have to weigh the cost/benefit of hanging around in big social groups. Sure, you could "chat more" with your friends, and get help fishing, but you'd also be competing for resources too (from female otters to food). This is why otters poo in latrines. The latrines act like the world-wide-web for otters, it's a communication in stinky that keeps them up to date on the neighbors and allows them to live alone (like most female river otters) or in small groups (like most male otters), while being in a larger community. There is some debate in the river otter world about whether or not otters are territorial, so spraints are really more communal than purely territorial.

This is an example of a bit older otter spraint, usually they are a touch darker grey but this one has been outside a week or so (Photo: K. McDonald)

Spraints contain a lot of information.

It is known that otters can differentiate their own poo smells, that of others, and the estrus state of females (if she's breeding or not). These poo-grams are also thought to convey information about who is in the "hood," and their health as well. Not only do otters spread fecal-facts but they also rub at the sites, leaving behind scent and smell as well. Green and Monick, Journal of Ethology, found that otters actually spend more time, standing, sniffing, and rubbing at spraint sites than just pooing.

Otter's don't just make spraints, they also make "anal jelly." 

We're not talking about the canning kind of jelly here, we're talking full on stinky intestinal lining. Otter anal jelly is not the kind of jelly you're thinking of either. It's thought to be the shedding of the intestinal lining of the otter, along with some undigested bits of food, and anal secretions to add some aroma. Anal jelly is usually not the same color of spraints, and it has a jelly-like consistency. The anal jelly I've seen is usually white or tan, and makes a stinky puddle. these jelly filled poos are also found at latrines, and scientists use them to harvest DNA for studies of individual otters. It's easier to get DNA from stomach lining than from poop. Yes, scientists have studied this (for European otters mostly) and you can read all about it here.

Otter anal jelly (Photo: K. McDonald)

River otters sometimes dance when they poo. 

One of the rituals that river otters are known for is something called the "otter poop dance." Yes, it's a real thing. I'll share a video below, you can also find several on Youtube. I've not found any good reason for this ritual, but it makes me laugh.

We can learn a lot about what an otter eats from its poo. 

There is a world of information that otters can get from each other's poo, but scientists find it useful too. Here are just a few ways scientists can:

  • Tell what a river otter eats and what is in season (from crayfish to crabs and fish to ducks)
  • Age the fish that the otters eat by counting the rings on the fish scales (like tree rings), this gives an idea of the age of the populations of fish they are eating, and their health
  • Estimate river otter populations by sampling DNA, looking at frequency of the spraints being laid down and how fresh they are
  • Track the estrus cycles of female otters and when they are ready to breed
  • Monitor fission-fusion events in otter populations, this is fancy science speak for when groups of otters come together to be social, and when they break up into smaller groups to hunt and forage. Fission-fusion events have implications on disease rates, information transfer, and the change in group dynamics (who goes to hang out with whom).

Yes, there is a protocol for cleaning otter spraints to get this information, it involves dish soap, shaking, sieving, and baking (to kill off parasites/bugs), but it's surprisingly not as smelly as you may think. In our region the spraints are mostly made up of fish scales and a few duck feathers, with crabs thrown in during the warmer months. These aren't so smelly with the flesh removed by the otter by its digestive system.

Fish bones and scales from a river otter spraint (Photo: K. McDonald)

Spraints can also tell us about the health of an otter.

Studies about European otters showed that in one project over 36% had Toxoplasma gondii, which comes from domestic cats. A study by researchers at UC Davis in California found the same issue, sea otters were also infected by the single celled parasite Toxoplasma (also called Toxoplasmosis), which comes from runoff from the land. Otters found near heavy freshwater flows from land are 3x more likely to be infected than those not near freshwater flows. This is thought to be a major contributing factor to the decline in sea otter populations in the region.

River otter spraints can also have other parasites too, ranging from different types of nematodes to trematodes (worms, don't worry about the names, just flat or round). Where I work we've found lots of long round-worms in the spraints, possibly trematodes, or worms that live in mollusks and whose life cycle requires mammal guts and later a snail for reproduction (nature is so weird and cool).

Nematodes or worms found in otter spraint (Photo: K. McDonald)

Otter latrines are geographically specific. 

Otters, like people, like to hang out in conspicuous places (at least to them). After all, you want to leave your poo-pori laden stink at the place where there are the most otters. To find otter latrines scientists did a bit of work trying to figure out what makes a latrine site just about as desirable to otters as malls to teenagers. Typically otters like to mark in areas of high traffic, where either trails or water bodies intersect, and areas that are fairly undisturbed by people as well as easy to watch from for predators. These areas are different depending on if you're studying in inland Colorado or the Chesapeake Bay. For us it's floating docks and finger piers. Knowing where otters like to be social, and spraint can help researchers study them. There are whole papers on multivariate statistical analysis of potential otter latrine sites (if you're looking for some light bedtime reading).

Spraints could be used to track other local carnivores. 

Let's face it, if you're a giant carnivore researcher tracking bears and pumas, wouldn't it be easier not to have to chase after them, trap them, tag them, etc.? Well, there may be an easier way, you got it, otter poop! Scientists in New Jersey used camera traps located at otter latrines to see if they could capture images of other carnivores that might be drawn to the spot by the smell. They found that all sorts of animals were drawn to the traps:

"....the overall carnivore detection frequency was 3.5 times greater at latrines, and the detection frequencies for red foxes (Vulpes vulpes), northern raccoons (Procyon lotor), river otters, mink (Neovison vison), long-tailed weasels (Mustela frenata), and Virginia opossums (Didelphis virginiana) were greater at latrines. American black bears (Ursus americanus) and eastern coyotes (Canis latrans) where detected more frequently at non-latrines. Our study provides evidence that placement of camera traps at otter latrines may serve as a new and novel approach for monitoring carnivore populations in riparian areas (Wagnon and Serfass, Ecology 2016)."

Can you spot the fox visiting this latrine? (Photo: K. McDonald)

Bet you didn't know there was a lot to learn from river otter scat. Regardless of whether or not you find poo to be too disgusting to deal with, or you find it funny to joke about, it's a real tool for researchers. When you're out and about, along rivers or lakes, keep an eye out for otter spraints, and see if you can tell what they have been eating, and who has been visiting.

Just because it's fun, here's another otter poop dance (4 minutes of otter poop dance fun).





Opossums Eat Ticks and Help Humans

Baby opossums (Photo: Flicker Sharinng,by Cryptozoo)

Why Opossums Get Ticked-off

Let's face it, ticks are one of those creatures that everyone hates. Even I, the biggest nature nugget of them all, hate ticks. They're flat and creepy and they invade the private moist areas of the human body that only my doctor and I should have access to. As if that's not enough, they bury their mouth parts in our skin, latch on, and suck our life-blood all while possibly transferring diseases. This creates a real ick factor that keeps many people out of the woods altogether.  However, there is some hope, namely because there is a cadre of creatures that eat ticks. There are the usual suspects of beetles, ants, centipedes, and other generalist eaters that wipe out ticks, but this list also includes chickens and ground fowl such as guinea birds and bobwhites. There's even an African bird called an oxpecker, which lives in sub-Saharan Africa that eats ticks off water buffalo and other hoofed animals (and who doesn't love that name!?). Well, since we're short on oxpeckers here in the Eastern US we have to rely on another creature to help us out, namely the Virginia opossum (Didelphis virginiana).

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What's the Difference Between Moles, Voles, and Shrews?

Eastern mole (Photo: Flicker Sharing, Dave GovoniL)

A Quick Chart and Guide

I hate it when the first online search results for any creature involves their death and killing, and moles, voles, and shrews are no exception. This post will walk you through the differences between these three distinct types of animals that show up in yards but that are often confused and misunderstood. I won't give you management information here, that's up to you, but at least this will help you understand the animals you may be living around and with.

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Cut Purring As a Means For Healing Bones

Buster Wigglebottom the First doing his best impression of a pretzel, while purring. (Photo: Karen McDonald).

Acoustic Healing and Purr Therapy

Whether your a cat person, a dog person, or a friend to other types of animals, you may soon come to appreciate the common household cat for something other than sitting in your lap and shedding. Researchers are conducting studies on cat purring as a method for healing bones, encouraging blood flow, the repair of muscles and encouraging tissue regeneration. Your trip to the doctor may some day include purr therapy.

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Fluid Support of the Hydrostatic Skeleton

Sea anemone's have hydrostatic skeletons (a tube within a tube). (Photo: Wiki Commons).

Spineless Doesn't Mean No Support

Have you ever heard the words:  "You're spineless?"  While meant as an insult, it's actually a compliment in biological terms. You probably already know that some animals, like humans, have internal skeletons (endoskeletons), and some have external skeletons (exoskeletons), like insects. But the story doesn't end there, nature is much more complex and diverse. There is an entire class of organisms that has a type of skeleton, called a hydrostatic skeleton. It is just like the name implies, a static skeleton made of fluid (hydro).

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Coywolf:  A New Species of Canid Emerging

coywolf wiki
Coywolves bred in captivity (Photo: Wiki commons). These hybrids are examples of interbreeding, but differ from the ones found in the eastern third of North America.

Coywolf (Wolf x Coyote) 

Coyotes (Canis latrans) have always been the one species of canine that receives the short end of the stick of public opinion. The Looney Tunes character isn't portrayed as the brightest creature on Earth and many native myths have the coyote featured as a trickster and schemer. Coyotes are the only species of wild canine in the US that do not have an specific hunting season, and so they are hunted year round as a pest and trouble maker. Despite all this, they are clever animals, capable of surviving in extreme conditions, adapting to the presence of humans, modifying their litter rates, and eating just about anything they can get a hold of. They are so good at surviving that they don't need protection or help. Coyotes are masters at adaptation and now they are adapting again.

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Distinguishing the Differences Between Rabbits and Rodents: Why Rabbits are Not Rodents

easter rabbit wiki

Photo: Wiki Commons

It's All In The Teeth...Well, Actually There's More.....

The iconic image of spring is that of rabbits and bunnies, and for those with a chocolate penchant the Cadbury bunny and his chocolate eggs.  In honor of Spring I decided it's time for a post on the confusion I commonly find, when leading programs, about why rabbits are not rodents. First, there's a wide range of rodents living in the world, in fact it's the largest class of mammals. They're everywhere and on nearly every continent. Rodents can range in size from .25 oz (the African pygmy mouse) to the capybara which can weigh from 150-200 lbs!

Notice in this drawing how the rodent's incisors don't have a root and grow continually. (Photo: Wiki Commons)

The order Rodentia, from which rodents get their name, derives from the Latin meaning "to gnaw or chew." This is what makes them unique, their teeth. Dentition is a commonly used feature for biologists to sort animals into families and orders. Rodents are specialized gnawers. They all have one set of upper and lower incisors (front teeth) and varying numbers of molars and per-molars (flat teeth in the back of the mouth) with a gap in-between called the diastema. Rodents lack canine teeth. The outer surface of rodent incisors is covered with enamel which ranges from orange to orangish-yellow in coloring (If you find a skull with these colors on the incisors it's always a rodent). It's thought that this coloring is due to strengthening by the addition of iron and minerals. The front of the tooth is very hard compared to the back of the tooth which is covered in dentin, a soft pulpy material. Unlike humans, whose teeth stop growing when they reach a certain stage, a rodent's incisors erupt/grow continually. This is called indeterminate growth. The tooth can continually grow because the base of a rodent's incisors is rootless and open so the tooth keeps growing. Human teeth have roots and are mostly closed off because the teeth do not need to grow anymore.

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An Introduction to Bats and Echolocation (and Tools to Use in the Classroom)

Bats Can Be Identified Through Their Unique Echolocation Patterns, They Even Have Dialects

Chirp, Chirp, Chrip Yall'

Desert long eared bat wiki
Desert long eared bat (Wiki commons)

As an undergraduate my introduction to field research was through bats. I studied under Dr. John Leffler, a student of EO Wilson, and spent countless hours recording bat sounds and trying to match their sounds to visual patterns that were species specific. If my life had gone differently I might still be studying bats and hanging from ropes welding bat gates. Even though I moved on from bats, to birds, and then outdoor education, I still have a mad passion for them and bat programs are one of my favorites. Thus, I'll do a series of posts on bats in the coming months in tribute to these amazing flying mammals. Today let's start with echolocation.

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Distinguishing the Features of Antlers V. Horns

The differences between antlers and horns is greater than you think.

Often when guiding hikes outdoors in the fall we'll see a deer with a nice rack of antlers on their head. One of the common misconceptions is that deer have horns. This post will help you learn the difference between antlers v. horns.

caribou antlers wiki
Caribou with Antlers (Wiki Commons)


Antlers are found only on members of the deer or Cervidae family. Members of this family include white-tailed deer, mule deer, black-tailed deer, moose, elk, reindeer, and antelope. Mostly it's the male deer that have antlers. Female caribou are the only female cervids that have antlers.

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