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VideoMedia Spotlight West African A living ’s biological and behavioral

For the complete video with media , visit: http://education.nationalgeographic.org/media/west-african-lungfish/

Funder

West African lungfish are prehistoric . They have survived unchanged for so long (nearly 400 million years) that they are sometimes nicknamed “living .” have remarkable adaptations that have helped them survive: a primitive and the ability to survive in a state of estivation, which is similar to .

A lungfish’s lung is a biological . A biological adaptation is a physical change in an that develops over time. Like all , lungfish have organs known as to extract from . The biological adaptation of the lung allows lungfish to also extract oxygen from the air.

A lungfish’s estivation also involves a number of biological adaptations, including the excretion of a “cocoon” and of the fish’s own muscle tissue to obtain nutrients.

A lungfish’s estivation also includes a behavioral adaptation. A behavioral adaptation describes a way an organism acts. Prior to estivation, lungfish furiously into the muddy ground. The behavioral adaptation of burrowing allows lungfish to create a protected habitat where they can survive during a long period of .

Watch this video, from the Nat Geo WILD series “Destination Wild,” and use our glossary to help answer questions in the Questions tab. Learn more about these fascinating fish with our Fast Facts.

Questions How has the West African lungfish’s primitive lung helped the survive for more than 300 million years?

1 of 5 During the dry season, the West African lungfish can breathe (extract oxygen from the air) as and turn to and cracked earth.

As the rainy season restores the lungfish’s aquatic habitat, it can rely mostly on its gills to extract oxygen from the water.

How has the West African lungfish’s estivation behavior helped the species survive for more than 300 million years?

The lungfish creates a mucus “cocoon” prior to estivation. The cocoon traps moisture and lets in air as the fish estivates. As the of the lungfish slows, it digests muscle in its to consume nutrients and stay alive. The burrowing, mucus cocoon, and self-digestion allow the lungfish to survive years beneath the dry landscape.

Fast Facts The West African lungfish digs its burrow using its mouth. It chews through the moist earth, excreting the mud through its gills.

West African lungfish have a very slow metabolism. This means they are much less active than other fish, and often rest at the bottom of a lakebed or riverbed. In fact, West African lungfish are so inactive that many owners mistakenly think their fish is dead!

The largest specimen of West African lungfish was a meter (3.3 feet) long and weighed a whopping 4 kilograms (nearly 9 pounds).

The West African lungfish is an . It feeds on everything from , fish, and mollusks to tree roots and . Although larger fish and may prey on juvenile lungfish, the adult lungfish has no major predators.

There are four species of African lungfish. (The one in the Destination Wild video is the West African lungfish, found in freshwater habitats throughout sub-Saharan .) Other species of lungfish are indigenous to and .

Vocabulary Part of Term Definition Speech a modification of an organism or its parts that makes it more fit for existence. adaptation noun An adaptation is passed from generation to generation. air noun layer of gases surrounding Earth. aquatic adjective having to do with water. behavioral way an organism acts in to survive or thrive in its environment. adaptation noun

2 of 5 Part of Term Definition Speech biological physical change in an organism that results over time in reaction to its adaptation noun environment. burrow verb to dig a small hole or tunnel. silky covering spun by silkworms and other larvae in which they live and cocoon noun develop during the pupal stage. consume verb to use up. process in breaking down ingested into easily absorbed and assimilated digestion noun substances by the action of and other agents. dormant adjective state of minimal growth or activity. dry season noun time of year with little precipitation. earth noun soil or dirt. estivation inactive state resembling deep sleep, in which some animals living in hot noun climates pass the summer. excrete verb to discharge a substance from the body. extract verb to pull out. furious adjective having a wild or violent passion. gills plural respiratory organs that draw oxygen from water and into the bloodstream. noun environment where an organism lives throughout the year or for shorter habitat noun periods of time. hibernationnoun condition, similar to sleep, in which some animals spend the winter. noun body of water surrounded by land. landscape noun the geographic features of a region. organism that is a living example of an otherwise extinct group or that has noun remained virtually unchanged in structure and function over a long period of time. lung noun in an that is necessary for breathing. metabolismnoun chemical changes in living cells by which energy is provided for vital processes.

3 of 5 Part of Term Definition Speech moisture noun wetness. mucus adjective,slimy, fluid secretion of some animals. noun mud noun wet soil. muscle noun tissue found in animals that expands and contracts, allowing movement. nutrient noun substance an organism needs for energy, growth, and life. obtain verb to get or take possession of. organism noun living or once-living thing. physical adjective having to do with the body. noun small body of water surrounded by land. prehistoric adjective period of time that occurred before the invention of written records. prepare verb to assemble or get ready for something. primitive adjective simple or crude. prior adjective before or ahead of. protect verb to take action to prevent injury or attack. rainy time of year when most of the rain in a region falls. season noun remarkable adjective unusual and dramatic. noun breathing. restore verb to renew or bring back to an earlier position or state of health. tissue noun cells that form a specific function in a living organism. Images Primitive :

Video BBC: The Lung Fish

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