- Class: Sarcopterygii
- Order: Lepidosirenifomes
- Family: Protopteridae
- Genus: Protopterus
- Species: P. annectens; P. aethiopicus; P. amphibius; P. dolly
A fish in—and out—of water. The African lungfish is certainly a fish for the ages. Unchanged for nearly 400 million years, these prehistoric animals are sometimes called “living fossils.” The secrets to its eons of existence? Adaptations! They have two lungs (like ours) and can breathe air. Since this species lives in flood plains in waterways that can dry up, this is a huge advantage. Able to survive in water or out, African lungfish are here to stay.
“Eely, eely” interesting. Measuring up to a little over three feet (one meter) in length at adulthood, African lungfish look like eels with long, thin limbs that allow them to lift and propel themselves forward. They can also take alternating “steps” with these rear “fins,” giving them little hop-like movements. The snout is prominent; eyes are small. The African lungfish’s dorsal (back) side is lighter, and its body and fins are dotted with black or brown spots. And although they have gills, lungfish have true lungs, and they breathe through their mouth as well as respire through their gills. In fact, they must have access to air, or they will drown.
The water’s fine—but so is the mud. African lungfish live in freshwater swamps, backwaters, and small rivers in West and South Africa in countries including Senegal, Niger, Gambia, Western Sudan, Cote d’Ivoire, Sierra Leone, and Guinea. A tropical fish, this species is most comfortable in water temperatures ranging from 76 to 86 degrees Fahrenheit (24 to 26 degrees Celsius).
Thanks to its unique physiology (lungs), the African lungfish can breathe when water dries up. This species gets approximately 90 percent of its oxygen from air. It digs its way into mud and surrounds itself with a secretion that will allow it to survive for up to four years, although it’s usually only for a matter of months.
HABITAT AND DIET
Destination estivation. Once the lungfish reaches the desired depth, it wriggles around, hollowing out a cozy cocoon, but leaves a short tunnel through which it can get air. During this state of suspended animation, lungfish are inactive for an extended period—they take in no food or water and make no urine or waste. They enter a state of torpor, almost like hibernation.
Watch out for the little guys. While larger fish and mammals may prey on juvenile lungfish, adult lungfish have no major predators. Maybe that’s why they have existed for hundreds of millions of years!
A little of this, a little of that. Omnivores, African lungfish hunt frogs, fish, and mollusks; and they will also eat tree roots and seeds.
A united effort. Female African lungfish lay their eggs in a nest in a weedy area of their habitats. Once the eggs hatch, it’s dad’s turn—the males guard the young for up to two months. The larvae have external gills that are reabsorbed during their metamorphosis into fully developed lungfish. As the African lungfish develops from juvenile to adult, its teeth fuse together to form tooth plates, which are used to chew its food.
AT THE ZOO
West African lungfish P. annectens are among the species planned for the San Diego Zoo’s new Sanford’s Children’s Zoo.
All four species of African lungfish are listed as species of Least Concern. Hooray!