lungfish

Lungfish aren't your average fish. While most fish rely entirely on gills to breathe underwater, these fish also have lungs. This lets them gulp air and survive in water with very little oxygen. Some species can even live through dry periods by burrowing into mud and becoming inactive until the rains return.

Think of them as some of the great survivors of the fish world, able to handle conditions that would kill many other water animals. You might see this word when learning about evolution, fossils, or unusual animal adaptations.

Lungfish are a fascinating group of freshwater fish found in Africa, South America, and Australia. What sets them apart from most other fish is their ability to breathe air using lungs. This adaptation helps them live in swamps, marshes, and rivers where the water may have very little oxygen. They still have gills, but the lungs become especially important when conditions are poor.

But that is only part of the story. Some species show remarkable resilience during dry seasons. When ponds or rivers shrink because of drought, they burrow into the mud, form a cocoon-like covering, and enter a dormant state called aestivation. Their bodies slow down so much that they can survive for months, and in some cases even longer, until the rains return.

Scientists consider lungfish to be one of the oldest living groups of vertebrates, and they are especially important because they are closely related to the early line of animals that later moved onto land. Studying them helps scientists understand major steps in the story of evolution. You might read about them in documentaries about evolution, articles on endangered species, or textbooks on animals, fossils, and ancient life. They are often described as a window into the past because they show how unusual body features can help an animal survive in difficult environments.