Jellyfish Aren’t Just for Saltwater

By Adrienne Montgomerie

“Mom, we saw jellyfish!”

“No way. We’re in a lake. Jellyfish are saltwater creatures.”

“No, really, honey," his dad said. "There were jellyfish.”

“Well that’s cool,” I said with total skepticism.

The next day, I said I wanted to see the jellyfish. Totally bracing for the “we’re just kidding” punchline, off we went.

Canoeing into a little bay of a medium sized lake in eastern Ontario, my son dipped a pail in the water, and pulled up several jellyfish about the size of a quarter. White, but mostly transparent. They looked almost like large contact lenses. Delicate, undulating in the green bucket.

The bay was full of them. A bloom of jellyfish. In fresh water.

They didn’t sting. Or if they did, they were so small that it was hard to tell. I didn't want to touch them because they are so delicate. I had to learn more about this.

It turns out that these jellyfish (C. sowerbii) are an invasive species, and they are quite widespread across North America. You can report sightings of them on the Freshwater Jellyfish website.

How Long Have Jellyfish Been in North America? 

This year there are thousands of news reports about the freshwater jellyfish, but there have been confirmed sightings in Canada and the USA as far back as 1934. There are even reports from the 1800s in London, England. Sightings are reported throughout Canada and the USA, but that 1934 sighting was in Horseshoe Lake near Ste. Agathe-des-Monts, Quebec.

How Can I Get a Closer Look?

If you want a closer look at these jellyfish, you can scoop some up in a clean bucket for a few minutes. Be sure to gently put them back where you found them. Check the sightings at FreshwaterJellyfish.org to find a likely lake.

They are big enough to see with just your eyes, but a magnifying glass will help you get a closer look.

The adult stage only lasts several days, so you may not find them when you go to look. It takes about a month for a jellyfish to grow. I saw them bloom on a very warm weekend one Thanksgiving but there are many reported sightings in mid-summer.

Where Did Freshwater Jellyfish Come From?

They probably came in the water inside a ship from South America, or on imported water plants from China.

They are found in crystal clear water, in slimy ponds, and in every kind of water in between.

How Can We Help Prevent Them from Spreading?

Clean boats and water toys in hot soapy water, just as you would to stop the spread of zebra mussels and gobies.

Don’t take plants from an infested place and put them in a new place.

Can you Keep at Jellyfish at Home?

Delicate and eerie, jellyfish have a mesmerizing appeal. Like any wild animal, they are healthiest when left in the wild. Like any invasive species, it’s best not to transport them to new areas, where they can infest more lakes.

Aquariums that keep jellyfish find it very difficult. None have been able to keep freshwater jellyfish on display. They usually only live a few days in captivity.

It takes special equipment to keep the pH correct and the water circulating continuously, and they need a constant supply of fresh plankton. Raising jellyfish takes a lot of attention. An aquarium is hazardous itself, as the delicate jellyfish can get sucked into filtration systems and pumps, and air bubbles can get trapped inside the jellyfish, holding them at the surface.

Are Jellyfish Harmful?

Freshwater jellyfish do sting, but their stinger is so small that it can’t seem to penetrate human skin. Some people do feel an irritation but it seems to be easily washed off.

It’s not yet known how these creatures will affect the ecosystem. They do eat plankton, which other species rely on, creating competition for the food. They are also eaten by gulls, crayfish, and turtles, providing new food that may help those species thrive (which in turn can affect other species that compete and rely on those animals). Few organisms have a zero sum impact on the environment they live in. We just haven’t seen the full effect yet.

The Endangered Caribou

By Marie Powell

CC Jacob W. Frank

The caribou (Rangifer tarandus) is a remarkable animal. Part of the deer family, caribou are unique because both males and females have antlers. Also known as reindeer, caribou have roamed North America for some 1.8 million years. Barren-ground caribou evolved from these early ancestors. The Woodland and Peary caribou have been with us since before the Pleistocene epoch, or Great Ice Age.

The thing I like best about writing middle-grade non-fiction books is that you're always learning something new. The research I'm doing this week has led me north to the Yukon and Nunavut, where I've been learning about the caribou. For instance, some populations of caribou have been reduced by 95 percent in the past 15-20 years. That seems incredible.

I've also been reading Bill Waiser's A World We have Lost: Saskatchewan Before 1905, and his vivid description of the buffalo herds on the prairies a century ago. These buffalo created a whole ecosystem just by foraging on the land, Waiser says. The wanton slaughter of some 4-5 million buffalo in the 1870s led to famine and severe environmental change across the prairies. Looking out my window at the busy streets of Regina, I try to imagine how different life would be today if that hadn't happened. So, when I read about the decimation of the caribou herds, I can't help but wonder what effect this will have on our future.

CCAlfred Cook  

Caribou fall into two groups: populations that remain in one area and spread out there after calving (sedentary), and herds that move or migrate to a common calving area each year (migratory). They range across the tundra and boreal forest areas, from the Arctic and south into most Canadian provinces. As well as predators and hunting, changing weather patterns affect the foraging of migrating herds, which in turn affects the health of the females and calves. So does loss of habitat due to human development in northern regions. All of this threatens the caribou's survival.

Scientists are working together with the Inuit to see how changing weather patterns affect the ecosystem of the north. For example, studies of the sea ice show how important that ecosystem is to all life in the north. One resource that brings out these findings is the Inuit Siku (Sea Ice) Atlas at http://sikuatlas.ca/sea_ice.html, as Claire Eamer shares in her Sci/Why post from 2013.

CCAllen Shimada 

Researchers have also turned to traditional Inuit knowledge to try to save the caribou. A 2012 report calls for minimizing development activities in caribou ranges, among other suggestions. Governments have responded with what the CBC calls a "patchwork" of conservation activities. Some provinces -- like Saskatchewan -- moved to limit development, and more recently others (including Alberta) have begun to act along those lines as well.

Will our efforts be in time to save these majestic animals?

Here are some more links to information about the Arctic and the caribou:

Bergerud, A. T. “Caribou.” The Canadian Encyclopedia. http://www.thecanadianencyclopedia.ca/en/article/caribou/

Braun, David Maxwell. "Inuit Knowledge Critical to Arctic Science." National Geographic Society , August 18, 2011 http://voices.nationalgeographic.com/2011/08/18/inuit-knowledge-critical-to-arctic-science/

Eamer, Claire. "Over, under, and on Arctic sea ice." Sci/Why 2013. http://sci-why.blogspot.ca/2013/03/over-under-and-on-arctic-sea-ice.html

Lunn, Susan. "Caribou still under threat despite changing political climate, report says." CBC News, Dec. 14, 2015. http://www.cbc.ca/news/politics/caribou-still-under-threat-despite-changing-political-climate-report-says-1.3359751

Northern Involvement: Changing Animal Populations - Science Canada - July 22, 2016 http://www.science.gc.ca/default.asp?lang=En&n=CC02ABC9-1
https://www.youtube.com/watch?v=99f_VVHuR2I&feature=youtu.be 

Rudolph, T. D., Drapeau, P., St-Laurent, M-H. and Imbeau, L. 2012. "Status of Woodland Caribou (Rangifer tarandus caribou) in the James Bay Region of Northern Quebec." (Scientific report) http://www.gcc.ca/pdf/Final-Rapport-Status-of-Woodland-Caribou-James-Bay_Eeyou-Istchee.pdf

"Traditional Inuit knowledge combines with science to shape weather insights." Science Daily, April 7 2010. https://www.sciencedaily.com/releases/2010/04/100407190000.htm

Weatherhead et al. "Changes in weather persistence: Insight from Inuit knowledge." Global Environmental Change, 2010; DOI: 10.1016/j.gloenvcha.2010.02.002 http://www.sciencedirect.com/science/article/pii/S0959378010000087

Marie Powell lives on Treaty 4 land in Regina, Saskatchewan. She is the author of close to 40 children's and young adult books, including the historical fantasy Hawk (2015). She enjoys writing about science, history, and any subjects that help promote literacy.

The Scoop on Sloth Poop

By Jan Thornhill

Illustration from Kyle Goes Alone (Illustration: Ashley Barron)

I didn't plan to write a book about pooping sloths—honest, I didn't. What I planned was to write a fairly straight-forward information book about the myriad forms of life that call a rainforest tree "home." I started, as usual, by simply gathering information about likely candidates that I could focus on: snakes; frogs; birds; vines and lianas; insects; fungi; bromeliads and other aerial plants; and, of course, mammals. It was all coming together nicely...but then I hit on sloths.

(Fernando Flores, Wikipedia)

I've always liked sloths, those sleepy-eyed characters that hang upside with goofy grins on their faces, moving unbelievably slowly or not moving at all. I actually emulated sloths in my teens, at least that's what my parents suggested, though they usually just used the word "lazy."  

(J.C.D. Schreber, Die Säugthiere in
Abbildungen nach der Natur, 1855)*

So I started reading about sloths and it wasn't long before I came across the kind of startlingly wonderful information that makes my heart sing: sloths only poop once a week. And why do they only poop once a week? Because sloths really are slow. In fact, not only are they so slow-moving that researchers' motion sensing cameras are sometimes not triggered when they pass, their digestive processes are the slowest of any mammal.

(Charles Dessalines d'Orbigny, 1849)*

Sloths primarily eat leaves. Tree leaves, particularly thick, long-lasting tropical tree leaves, are not packed with nutrients, nor are they easy to digest since their cell walls are made up of cellulose and lignin—just like a tree's wood, bark and branches. The only way a sloth can digest this tough stuff is with the help of gut bacteria, and this process takes a long time—a single leaf can take a month to travel from one end of a sloth to the other! 

(J.C.D. Schreber, Die Säugthiere in
Abbildungen nach der Natur, 1855)*

I also learned that some sloths add another fascinating bit of behaviour to this slow digestion. Three-toed sloths only poop on the ground, despite the ground being an unbelievably dangerous place to spend time for a creature whose hanging-upsidedown-from-trees anatomy is ill-suited to walking—more than half of all sloth deaths are caused by predation during these weekly excursions. 

(1776)*

And then I found this video of baby sloths being "potty trained" at a sloth rescue centre in Costa Rica—just about the cutest thing I've ever seen. And suddenly I wasn't working on the book I thought I was working on anymore. Now I was writing a picture book called Kyle Goes Alone (Owlkids Books, illustrated by the brilliant Ashley Barron), the story of a young sloth's first trip to the ground alone, cheered on by camouflaged rainforest neighbours. I managed to work much of the above sloth poop information into the book, but I didn't have room for the following, even more entertaining information. 

Two-toed sloth (Albertus Seba, 18th Century)*

Three-toed sloths carry their very own ecosystems in their fur coats. Their hair is grooved, and in the humid rainforests where they live, these grooves are a perfect place for algae to grow, algae that can be plentiful enough in the rainy season that a sloth can appear to be completely green—not a bad colour if you live amongst green leaves. Along with algae, sloth hair also harbours all kinds of fungi, ticks, mites, and insects. Some of the insects are moths that, as adults, live nowhere else other than between the hairs of a sloth's thick coat. Their other life stages—egg, larva, and pupa—are all spent in...drum roll, please...sloth poop.

(Frederick P. Nodder, 1789)*

Here's how this works: The adult moths, which have no mandibles, so likely don't eat, hang around on a sloth, seeking out another moth of the opposite sex. Then they do what they're supposed to do, which is procreate. Pregnant females wait until that happy moment when the sloth's weekly urge to "go" drives it slowly down to the ground. Once on the forest floor, the sloth, which often carries around a third of its body weight in waste (imagine!!), uses its tail to carve a little hollow in the ground, then defecates. This is, of course, the moment the female moths are waiting for. They crawl out of the sloth's hair and flutter down to the hard pellets where they lay their eggs. Once the eggs hatch, the larvae have ample food, particularly since they have the advantage of having arrived before any other forest dung-eaters. They eat to their hearts' content and then pupate. When an adult emerges, it flies upwards to search out some sloth fur to take up residence and seek out a potential mate—a sloth that is likely to be the same one its parents lived on since these animals are very fond of certain trees and don't stray far from them.

(1889)

So what do three-toed sloths get out of this relationship? No one yet knows, but one possibility is that the moths somehow fertilize the algae that grows in the fur, which the sloths in turn might eat to supplement their otherwise poor diets. Unfortunately, no one has observed sloths eating algae from their coats, but it's possible they might do this as night when they are notoriously difficult to observe. 

(Maximilian Wied, Abbildungen zur
Naturgeschichte Brasiliens, 1822)

Other researchers are unconvinced that there is a symbiotic relationship between the moths and the sloths. They think that the sloths' habit of pooping on the ground at the base of their favourite tree is more about communication and procreation with other sloths, especially since a female in oestrus will go down to the ground every day. If this is true, the moths might just be opportunistically hitching rides on sloths so they can be "delivered" to the poop their offspring need to survive. 

(Ashley Barron)

Kyle Goes Alone (written by Jan Thornhill, illustrated by Ashley Barron), Owlkids Books, 2015

Baby Sloths get Potty Trained Video



*Many early animal illustrators never saw the animals they depicted, hence some pretty fabulous sloth pictures!