This story was originally published in July 2018.

It was early in the season to see moss animals, Gudrun Keszocze explained as she steered the canoe to the shallows of Pushaw Stream in late June. When the water warms to a certain temperature, these strange creatures start to grow and multiply, building colonies just beneath the surface.

As the naturalist for Hirundo Wildlife Refuge in Old Town, Keszocze guides paddling trips on the stream on a weekly basis. She also leads educational programs about the waterway’s many inhabitants, including the mysterious moss animal.

“Oh, oh, oh! I think we got it,” Keszocze said in a hushed but excited voice as she stirred her paddle in the water, slowing the canoe.

Careful not to upend the boat, she reached into the water and pulled up a waterlogged branch. With it came a gelatinous orb that resembled an egg mass. About the size of a football, the colony of moss animals glistened in the sun and jiggled as Keszocze held it above the water.

“Their defense mechanism is along their scillia. They give off some sort of irritant,” Keszocze said. “And they actually give off a smell, a stinky smell. So they try not to be very appealing.”

Moss animals are just one of the many strange freshwater creatures in Maine that often go overlooked. Whether hiding in the shadows or darting across the water’s surface, these real life monsters are more fascinating than dangerous. Their survival tactics and adaptations make them uniquely suited for a watery world, from rivers to swimming holes. Here are just a few of these amazing creatures, starting with one of Keszocze’s favorites.

Moss animals

A moss animal at Hirundo Wildlife Refuge in Old Town. Credit: Aislinn Sarnacki / BDN

Moss animals, also called bryozoan, are filter feeders. Using tiny tentacles and cilia, they propel particles of food into their mouths. In Maine, these tiny invertebrate animals attach to underwater objects, such as sunken trees, and create colonies that can grow to become as large as a basketball and weigh several pounds. These tentacles give the colony a fuzzy or “mossy” appearance.

Water scorpions

A predatory insect, water scorpions use their long tail, not to sting, but to breathe. While hunting underwater for insects, spider and worms, they hold their tail above the surface to breathe through it, similar to a person using a snorkel. These creatures have slender, brown bodies that can grow to be more than 2 inches long, but they’re often overlooked because they’re frequently motionless, waiting just under the water to ambush prey. Look for them near the surface of still water, not only in ponds but also in slow-moving sections of streams and rivers.

Bloodsuckers

A leech at Hirundo Wildlife Refuge in Old Town. Credit: Aislinn Sarnacki / BDN

Probably the most common nuisance to swimmers in Maine is the leech. A worm-like animal that lives in freshwater habitats, the leech attaches to other animals — including humans — to feed on blood, which explains their nickname: bloodsuckers. Leeches are typically found in shallow water, hidden in plants and under rocks, and they’re most active on hot summer days, according to the Maine Department of Environmental Protection.

Water striders

A water strider at Hirundo Wildlife Refuge in Old Town. Credit: Aislinn Sarnacki / BDN

Walking on the surface of the water on long, spindly legs, water striders tread where others sink. These insects are covered with tiny hairs that repel water and trap air, plus they spread out their weight by stretching their legs out to all sides. Their mobility on the surface of the water allows them to easily prey on drowning insects. They also communicate to one another and detect prey drumming on the surface of the water, sending out tiny waves that relay back information about what’s nearby. These strange creatures, often in pairs or groups, can be found in ponds, vernal pools, marshes or any other area of quiet water.

Green sponges

A green sponge at Hirundo Wildlife Refuge in Old Town. Credit: Aislinn Sarnacki / BDN

While most of the world’s thousands of species of sponges live in saltwater, a handful of them thrive in clean, freshwater environments. Often mistaken for a plant, freshwater sponges are actually immobile invertebrate animals that filter water to find food. They grow on submerged objects, such as fallen trees and rocks; they have a coarse texture; and they are typically green due to the algae that lives inside their structures.

Water snakes

Measuring an average length of 3.5 feet, the northern water snake is found in a wide variety of aquatic habitats, according to the National Wildlife Federation, though they prefer slow-moving water or standing water. In Maine, this fairly large snake is only found in the southern half of the state. Preying on fish and amphibians, the species is often found in bogs, swamps, cattail marshes and wet meadows, according to the Maine Department of Inland Fisheries and Wildlife. And though they are not poisonous, they can deliver a painful bite.

Carnivorous water plants

While this isn’t a “creature,” it does eat creatures, so it makes the list. Common in Maine waterways, bladderwort is a carnivorous plant that consumes small aquatic organisms. With long, trailing stems, these plants are covered with little bladders. Hairs at the opening of each bladder triggers it to open when contacted, sucking water and any nearby organisms in to be digested by enzymes and bacteria.

Whirligigs

Whirligigs at Hirundo Wildlife Refuge in Old Town. Credit: Aislinn Sarnacki / BDN

Zipping around on the surface of the water, often in circles, whirligig beetles are a common sight in Maine, and while they can be a bit annoying to swimmers, they’re really quite harmless. These small, black beetles have split eyes so they can see below water and above water at the same time. This helps them evade predators (such as fish) while they hunt for insects. Found in all sorts of freshwater habitats, these beetles spend most of their lives on the surface of the water, where they absorb air from the atmosphere. But they also sometimes dive underwater, and when they do that, they tuck an air bubble under their wings for an oxygen supply.

Snappers

A snapping turtle basks in the sunshine on a rock in the Kenduskeag Stream. Credit: Linda Coan O'Kresik / BDN

With a powerful bite and long claws, snapping turtles are Maine’s largest freshwater turtle, and while they aren’t looking for a fight, they’ll defend themselves if provoked. Often referred to as “snappers,” these turtles can grow to be quite old and large, with a tough shell measuring about a foot long on an average adult, which typically weighs between 10 and 35 pounds. However, snapping turtles exceeding 40 pounds have been found in Maine, basking on lakeside rocks and swimming in search of food, which can vary from aquatic plants to birds and small mammals.

Fishing spiders

A fishing spider rests on a rock beside a stream in Baxter State Park. Credit: Aislinn Sarnacki / BDN

Maine’s largest native spider, the fishing spider can walk on water to snatch up insects and even small fish. But don’t worry — they’re shy. “They’d rather flee than fight,” according to online material about the spider provided by the University of Maine Cooperative Extension. And while they can bite humans, the bite is much like a wasp or bee sting unless the person who is bitten is sensitive to spider venom. And while the fishing spider can hunt on water, it’s more frequently found in the woods, and it’s a typical household invader, so there’s really no escaping this creepy crawly.

Aislinn Sarnacki

Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...