Reptiles
Alligator snapping turtle
Macrochelys temminckii
The alligator snapping turtle is North America's largest freshwater turtle. Facts on its ridged shell, worm-like tongue lure, size, lifespan, range and threats.
Habitat · 46 species
Animals of rivers and lakes
Freshwater animals of rivers, lakes and streams, from otters, beavers and hippos to trout and turtles.
Species profiles
Reptiles
American alligator
Alligator mississippiensis
The American alligator is a large crocodilian of southeastern US wetlands. Facts on its size, diet, nesting, gator holes and its comeback from near extinction.
Amphibians
American bullfrog
Lithobates catesbeianus
The American bullfrog is North America's largest true frog, up to 20 cm long and 500 g. Its size, deep call, diet, tadpoles, range and spread as an invasive.
Reptiles
American crocodile
Crocodylus acutus
The American crocodile lives in coastal mangroves from south Florida to Peru and Venezuela. Facts on its size, salt tolerance, nesting and Florida recovery.
Fish
Atlantic salmon
Salmo salar
The Atlantic salmon hatches in cold rivers, grows up at sea and leaps home to spawn. Its life cycle, size, diet, ocean journeys, threats and current status.
Amphibians
Axolotl
Ambystoma mexicanum
The axolotl is a Mexican salamander that keeps its gills and lives in water for life. Facts on its size, colors, diet, regeneration and endangered status.
Birds
Bald eagle
Haliaeetus leucocephalus
The bald eagle is North America's sea eagle and the US national bird. Facts on its size, white head, fish diet, giant nests, range, lifespan and DDT recovery.
Fish
Bull shark
Carcharhinus leucas
The bull shark is a stocky coastal shark that can swim far up rivers into fresh water. Its size, diet, river nurseries, risk to people and Vulnerable status.
Birds
Canada goose
Branta canadensis
The Canada goose is a large black-necked goose native to North America and introduced to Europe. Facts on size, migration, diet, nesting, lifespan and status.
Amphibians
Chinese giant salamander
Andrias davidianus
The Chinese giant salamander is one of the largest amphibians on Earth, up to 1.8 m long. Its mountain streams, diet, crying calls, farming and Critical status.
Insects
Common green darner
Anax junius
The common green darner is a large North American dragonfly with a green thorax and blue abdomen. Its size, hunting, nymphs and multigeneration migration.
Birds
Common kingfisher
Alcedo atthis
The common kingfisher is a sparrow-sized blue and orange bird of rivers in Europe, Asia and North Africa. Its size, fishing dives, burrow nests and lifespan.
Birds
Common loon
Gavia immer
The common loon, or great northern diver, is a large diving bird of northern lakes famous for its haunting calls. Size, diving, nesting, range and lifespan.
Reptiles
Common snapping turtle
Chelydra serpentina
The common snapping turtle is a big, rough-shelled freshwater turtle of North America. Facts on its size, powerful bite, diet, nesting, lifespan and range.
Reptiles
Cottonmouth
Agkistrodon piscivorus
The cottonmouth, or water moccasin, is a venomous semi-aquatic pit viper of the southeastern US. Its size, white-mouth display, fish diet, live young and range.
Fish
Electric eel
Electrophorus electricus
The electric eel is an air-breathing South American knifefish, not a true eel, that stuns prey with shocks of hundreds of volts. Size, habitat, diet and life.
Mammals
Eurasian otter
Lutra lutra
The Eurasian otter is a sleek, fish-eating member of the weasel family found on rivers and coasts from Ireland to Asia. Size, diet, holts, spraints, recovery.
Fish
European eel
Anguilla anguilla
The European eel grows up in rivers from Iceland to North Africa but is born in the Sargasso Sea. Its life cycle, size, diet, lifespan and why it is endangered.
Amphibians
Fire salamander
Salamandra salamandra
The fire salamander is Europe's black-and-yellow salamander of damp forests: toxic skin, live-born larvae and a long life, now Vulnerable due to Bsal fungus.
Reptiles
Grass snake
Natrix natrix
The grass snake is Europe's harmless, water-loving snake with a yellow collar. Its size, frog diet, compost-heap eggs, playing dead and the 2017 species split.
Birds
Great blue heron
Ardea herodias
The great blue heron is North America's largest heron. Facts on its size, slow flight, fish diet, treetop colonies, the white Florida form, migration and range.
Reptiles
Green anaconda
Eunectes murinus
The green anaconda is the world's heaviest snake, a giant boa of South American swamps and rivers. Facts on its size, hunting, breeding balls and live birth.
Reptiles
Green iguana
Iguana iguana
The green iguana is a large, plant-eating tree lizard of Central and South America that can top 1.5 m. Size, colors, diet, swimming, nesting and lifespan.
Amphibians
Hellbender
Cryptobranchus alleganiensis
The hellbender is North America's largest salamander: a flat, wrinkly, fully aquatic amphibian of clean, rocky Appalachian and Ozark streams, now Vulnerable.
Birds
Herring gull
Larus argentatus
The herring gull is the large gray-backed seagull of European coasts and towns. Facts on its size, plumage, diet, rooftop nests, chicks, lifespan and decline.
Mammals
Hippopotamus
Hippopotamus amphibius
The hippopotamus is Africa's giant river mammal: up to 1.5 tonnes or more, grazing at night and resting in water by day. Size, behavior, danger and status.
Mammals
Little brown bat
Myotis lucifugus
The little brown bat is a small North American insect-eating bat that can live over 30 years. Size, echolocation, colonies, hibernation and white-nose syndrome.
Reptiles
Nile crocodile
Crocodylus niloticus
The Nile crocodile is Africa's largest reptile and second-largest crocodile. Its size, range, hunting, nesting, danger to people and the West African split.
Mammals
North American beaver
Castor canadensis
The North American beaver is the largest rodent in North America, a dam-building wetland engineer. Its size, teeth, lodges, bark diet, family life and comeback.
Mammals
North American river otter
Lontra canadensis
The North American river otter is a playful, fish-eating otter of rivers, lakes and coasts in Canada and the US. Its size, fur, diet, family life and comeback.
Reptiles
Northern water snake
Nerodia sipedon
The northern water snake is a harmless banded snake of ponds and streams in eastern North America. Its size, range, fish diet, live young and cottonmouth ID.
Amphibians
Olm
Proteus anguinus
The olm is a blind, pale salamander of flooded caves in Slovenia, Croatia and Bosnia. Facts on its gills, senses, diet, century-long lifespan and conservation.
Mammals
Pygmy hippopotamus
Choeropsis liberiensis
The pygmy hippopotamus is a small, shy forest hippo of West Africa, mainly Liberia. Facts on its size, night life, diet, calves, Endangered status and Moo Deng.
Fish
Red-bellied piranha
Pygocentrus nattereri
The red-bellied piranha is a South American river fish with razor-sharp teeth, a varied diet and a fearsome but exaggerated reputation. Size, range and habits.
Reptiles
Saltwater crocodile
Crocodylus porosus
The saltwater crocodile is the largest living reptile. Its size, range from India to Australia, life at sea, hunting, nesting, recovery and the risk to people.
Birds
Scarlet macaw
Ara macao
The scarlet macaw is a large red, yellow and blue parrot of tropical American forests. Facts on its size, diet, clay licks, nesting, lifespan and conservation.
Mammals
West Indian manatee
Trichechus manatus
The West Indian manatee is a gentle, plant-eating sea cow of Florida and the Caribbean. Size, diet, warm-water needs, breeding, threats and Vulnerable status.