When we think about what lives in lake, we usually conjure images of fish, reptiles, amphibians, mammals, and birds. But some of the most important things that live in a lake are nutrients and microorganisms before we can have the above species. Lakes and ponds are scientifically named lentic systems. Without nutrients and microorganisms, we would not enjoy the other animals and marine life that live in or at a lake.
Photosynthesis in primary producers requires light transmission. Primary producers are periphyton, phytoplankton, and macrophytes. Biologists divide these producers into different groups. Smaller prey, called consumers, feed on the primary producers. The consumer species found in lake habitats include worms, snails, amphibians, crustaceans, insects, reptiles, fish, and birds. In turn, these species provide food for larger birds, mammals, and marine life.
So, What Lives in a Lake?
Lakes are crucial in preserving wildlife. All kinds of animals and birds depend on lakes because they provide much of the food sources for wildlife. Lakes also provide travel stops for migrating animals and birds. A lake’s physical characteristics and its ecological dynamics, even its circadian rhythms, affect the entire ecosystem around a lake.
A diversity of organisms, microscopic plants, animals, amphibians, birds, fish, mammals, and reptiles live in or at lakes. Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle. Almost all living things, humans, animals, plants, and microbes, respond to light and dark and circadian rhythms.
Other factors that affect how a lake supports a diversity of wildlife and marine life are biotic and abiotic factors, hydroperiods (the length of time and portion of the year the wetland holds water), water chemistry, nutrient inputs and cycling, nutrients, nitrogen, carbon, and phosphorus, and oxygen concentration. Oxygen concentration is complex.
The temperature of the water affects how oxygen mixes into the lake’s water and explains how a lake turns over. After summer, the warm top water cools and falls to the lower level. The water that the top water falls through is now on top. This replenishes dissolved oxygen, oxygen concentration equalizes, and circulation restores. This can happen twice a year.
Fish: From Small to Huge
The smallest known fish in the world found in lakes is the anglerfish species of the Photocorynus spiniceps. This fish is only 0.2441-inches long. The largest fish found in lakes is the sturgeon, which can grow to 20 feet and weigh over 1,500 pounds. Common fish species in U.S. lakes are trout, salmon, bass, catfish and perch. The northern pike is a common freshwater fish found in lakes all over the world.
The nine most common fish in the world in freshwater include the alligator gar, arapaima, bull sharks, giant barb, Mekong giant catfish, Nile perch, paddlefish, Siberian taimen, and white sturgeon. The 11 largest freshwater fish in the world are alligator gar, arapaima, beluga sturgeon, bull sharks, giant barb, giant freshwater stingray, Mekong giant catfish, Nile perch, paddlefish, Siberian taimen, and white sturgeon.
The eight smallest fish in the world are the celestial pearl danio, chili rasbora, corfu dwarf goby, dwarf pygmy goby, midget dwarf goby, paedocypris progenetica, photocorynus spiniceps, and stout infantfish. We divide fish into cold water fish and warm water fish. Common warm water fish are largemouth and smallmouth bass, muskellunge, northern pike, and walleye. Common cold water fish include several species of trout and salmon.
Reptiles: Alligators, Crocodiles, Lizards, Snakes, and Turtles
Dinosaurs were reptiles. There are a few other species of reptiles, like caimans and the Indian gharial. Reptiles breathe only through their lungs and have dry, scaly skin that prevents them from drying out. Their scientific name is herptofauna, and they are “cold-blooded”, meaning they lack an internal thermostat. They regulate body heat through their interactions with the environment.
Four reptile groups include species that live in lakes and other water bodies are turtles, lizards, snakes, and crocodilians. Crocodilians are alligators, crocodiles, and caimans. Some water snakes are poisonous and others are harmless. But sometimes even poisonous snakes that rarely live around water will hang around a lake, like rattlesnakes.
Amphibians: Frogs, Salamanders, Newts, and Toads
Amphibians begin their lives in water and then spend most of their lives on land. Most amphibians live on land near freshwater as adults. Amphibians first appeared 368 million years ago, as evidenced by the first known amphibian fossil discovered in Scotland’s Lake Devonian dating back to that time. Later in the Paleozoic era, amphibians ranged from small legless swimming forms to horned forms.
Eventually Amphibians, which were and are vertebrates, evolved to live in water and on land. Amphibians deposit larvae in water and the larvae breathe through gills. Adults breathe through their gills and lungs. You can find amphibians almost anywhere there is fresh water. There are no real amphibians in salty oceans, but some can live in slightly salty water.
Frogs and toads are the largest populations of amphibians. According to the Tennessee Wildlife Resource Agency, there are 4,963 species of frogs and toads in the world, and the World Wildlife Fund reports over 4,000 species. Nine of the ten families of salamanders live in the U.S. The Great Smoky Mountains National Park in Tennessee is called “The Salamander Capitol of the World”.
Mammals: Beavers, Muskrats, Otters, and More
Water is the lifeblood for mammals. Even city lakes attract wildlife mammals. Rural lakes usually attract a wider diversity of mammals. Lakes even provide a source of shelter for mammals. Lakes exist on every continent, and surrounding them are the mammals that depend on them. Mammals have a special bond with lakes and the mammals help to keep lakes clean.
Beavers, minks, muskrats, and otters are the most common mammals found near shorelines and make their homes at lakes. Mammals are the class of animals that have fur or hair, give live birth, and produce milk for their young. Where ever there is a lake, the mammals that inhabit that lake’s ecosystem will find the lake a source of food, shelter, and water.
If you live at a lake in Alaska, you will see bears. If you live at a lake in Wyoming, you will see elks. If you live at a lake in Africa, you will see hippopotamuses. Antelope, bats, bears, boars, buffalo, cougars and other cats, coyotes, deer, foxes, moose, rabbits, skunks, squirrels, and wolves all call the U.S. home and are common sightings at U.S. lakes, depending on where you live.
Birds that Live at Lakes
Biologists group birds that live at lakes into subclasses. They call them aquatic birds water birds or waterfowl, but there is a distinction between waterfowl and other birds that live part or all of their lives in and around lakes and other water bodies. To maintain each species, aquatic birds must be able to reproduce, survive, grow, and reproduce again, and lakes provide that habitat for them.
Marsh birds, shorebirds, wading birds, and waterfowl make up the subclasses of aquatic birds. The classification of the subclasses is based on the preferred habitat of aquatic birds. These aquatic bird’s habitat preference gives researchers the ability to make generalizations on birds with like requirements.
Marshes are treeless wet tracks of grass, sedges, cattails, and other species of herbaceous wetland plants. Swamps are wet, soft, low-lying, water-logged land dominated by trees and shrubs. Marsh birds include a large number of bird families and species, like cranes, flamingos, herons, ibises, limpkins, and rails. These are unrelated species that make their homes in marshy, swampy regions.
Open areas of beaches, grasslands, tundras, and wetlands attract shorebirds. Shorebirds have long bills, long legs, and long, straight toes, not claws. Their plumage and feathers typically have a dull hue. Their feet are ideal for walking in water and muddy areas. The most common species of shorebirds include avocets, oystercatchers, plovers, sandpipers, and stilts. Some species of shorebirds are also wading birds.
Wading birds wade in shallow water to search for food they cannot find on or near the shore. They typically have long bills, long legs, and short tails. These physical features allow them to explore underwater for and strike at prey and other types of food sources. They like aquatic insects, crustaceans, fish, and frogs. Some species include avocets, cranes, curlews, egrets, godwits, herons, ibises, spoonbills, and stilts.