Wetland Animals

Wetlands have water at or near the soil surface for all or part of the year, long enough to influence their soils and vegetation. They can be seasonal and need not look flooded on the day you visit. Marshes, swamps, bogs and fens are familiar types. A river or lake can have wetlands along its margins; the whole river or lake is not automatically a wetland.

The US Environmental Protection Agency's definition emphasizes water, soil and plants. Freshwater wetlands differ from coastal salt marshes and mangroves, where tides and salinity influence which animals can live there.

A useful way to compare wetland animals is to ask where they feed as well as what they eat:

• Capybara: a South American herbivore that grazes grasses and aquatic plants. Water also provides refuge and helps it keep cool.
• Hippopotamus: spends much of the day in water but usually leaves it to graze on land. Being tied to a river does not mean eating mainly underwater plants.
• Shoebill: an African wetland bird that catches fish and other prey among shallow water and vegetation.
• Platypus: an Australian carnivore that searches underwater for insect larvae, worms, crustaceans and other small animals.

Compare herbivores with carnivores, then follow each profile for its own range and feeding habitat.

Dragonflies show why life stage matters. Their larvae hunt underwater; after emerging, adults catch insects in the air. Protecting a breeding pool alone may not preserve all the surrounding feeding habitat an adult uses. The US Fish and Wildlife Service's dragonfly account describes this change from aquatic to aerial predator.

The collection also includes animals of connected freshwater habitats, such as axolotls in Mexican lake and canal systems and salmon moving between freshwater and the sea. Their presence here does not imply that every wetland supports them.

Wetland food webs depend on the timing, depth and quality of water. Drainage removes habitat; altered flows can change how long soil stays saturated. Many wetlands slow floodwater or retain sediment, but their functions differ with location and hydrology. Restoring water to a site is only part of understanding which plants and animals it can support.

• US EPA: wetland types and wetland functions
• San Diego Zoo Wildlife Alliance: capybara, hippo and shoebill
• Australian Platypus Conservancy: foraging behaviour