User:Myeverything5/West African lungfish

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The West African Lungfish, Protopterus annectens, are considered to be prehistoric animals due to their unchanging features for four hundred million years (San Diego Zoo Wildlife Alliance, n.d.). They are sometimes even referred to as “living fossils”, and can live up to twenty years (San Diego Zoo Wildlife Alliance, n.d.). The West African Lungfish is unique because it has many important body structures, a diverse diet, survival adaptations, a steady habitat, and an interesting life cycle.

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Body Parts and Structures

Their total length as adults is about one meter, and they weigh about 10 pounds (San Diego Zoo Wildlife Alliance, n.d.). They have small eyes, and contain dark spots all over their body (San Diego Zoo Wildlife Alliance, n.d.). They also contain limbs that lift them up to propel forward (San Diego Zoo Wildlife Alliance, n.d.). With these limbs, they can also take steps in a hop-like motion (San Diego Zoo Wildlife Alliance, n.d.).Lungfish breathe through their mouth using their two lungs, and respire through their gills (San Diego Zoo Wildlife Alliance, n.d.). It is important for them to have access to air for their survival (San Diego Zoo Wildlife Alliance, n.d.).

Habitat

Lungfish are mostly found in West and South Africa such as Guinea, Gambia, Senegal, Sierra Leone and Western Sudan (San Diego Zoo Wildlife Alliance, n.d.). They live in backwaters, rivers, lakes, and freshwater swamps (San Diego Zoo Wildlife Alliance, n.d.). They typically prefer to live in warmer temperatures from the range of twenty four to twenty six degrees Celsius (San Diego Zoo Wildlife Alliance, n.d.).

Diet

Lungfish are omnivores, and their diet consists of frogs, mollusks, roots, seeds, and other fish (San Diego Zoo Wildlife Alliance, n.d.). Lungfish can even go 3 and half years without eating (San Diego Zoo Wildlife Alliance, n.d.). They have slow metabolism, and rest at the bottom of its environment (National Geographic Society, n.d.). Adult lungfish have no predators, however, young lungfish can be preyed upon (San Diego Zoo Wildlife Alliance, n.d.).

Lifecycle

Lungfish eggs are laid in weedy regions by females, and once they hatch, the male lungfish guards the juvenile lungfish for two months (San Diego Zoo Wildlife Alliance, n.d.). During metamorphosis, the larvae’s gills are reabsorbed (San Diego Zoo Wildlife Alliance, n.d.). As the lungfish grows, its teeth are fused together, which forms tooth plates that allows it to chew its food (San Diego Zoo Wildlife Alliance, n.d.).

Aestivation

During dry seasons, there is a lack of water and moisture in the environment. When this occurs, lungfish burrows into the mud to survive (Delaney et al., 1974). This is referred to as aestivation (Chew & Hiong, 2014). There are three phases to this process (Chew & Hiong, 2014).

The first phase is referred to as induction (Chew & Hiong, 2014). In this phase is where the lungfish recognizes that a dry season is on its way through environmental cues and sensory signals (Chew & Hiong, 2014). It starts to burrow into a muddy ground using its mouth (National Geographic Society, n.d.). It chews through the soil with its mouth and removes the soil through its gills (National Geographic Society, n.d.). It secretes mucus when it hyperventilates which dries into a cocoon within six to eight days (Chew & Hiong, 2014). This cocoon is waterproof, and contains one small hole that is used for breathing (Delaney et al., 1974).

The second phase is the maintenance phase. In order to preserve its body structures, the lungfish prevents cell death and slows down the rate of waste production (Chew & Hiong, 2014). This helps to prevent pollution of its environment (Chew & Hiong, 2014). Furthermore, it depresses its heart activity, urine production, and food intake (Icardo et al. 2014). In addition, during this phase, it can obtain its nutrients by digesting its own muscle tissues (National Geographic Society, n.d.). They can stay in this phase up to four years  (San Diego Zoo Wildlife Alliance, n.d.).

The third phase is the arousal phase. The lungfish enters this phase when water returns to its environment (Chew & Hiong, 2014). Once it enters this phase, the lungfish eliminates its waste that accumulated during the second phase (Chew & Hiong, 2014). In addition, it begins to feed on food to repair damaged body parts and to grow (Chew & Hiong, 2014).

African Lungfish in Tank; Image Credit: Harum K, November 2014

References

Chew, S.F., & Hiong, K. (2014). Aestivation and the brain of the African lungfish Protopterus annectens. Temperature, 1(2), 82-83. doi: 10.4161/temp.29650

Delaney, R.G., Lahiri, S., & Fishman, A.P. (1974). Aestivation of the African lungfish Proptopterus aethiopicus: cardiovascular and respiratory functions. Journal of Experimental Biology, 61(1), 111-128. doi:https://doi.org/10.1242/jeb.61.1.111

Harum, K. (2014, November 19). African Lungfish. Wikimedia Commons. [Image]. https://commons.wikimedia.org/wiki/File:African_lungfish_(15779867175).jpg

Icardo, J.M., Wong, W.P., Colvee, E., Loong, A.M., & Ip, Y.K. (2010). The anatomy of the gastrointestinal tract of the African lungfish, Protopterus annectens. The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology, 293(7), 1146-1154. doi: https://doi.org/10.1002/ar.21154

National Geographic Society. (n.d.). West African Lungfish. National Geographic. https://education.nationalgeographic.org/resource/west-african-lungfish/

San Diego Zoo Wildlife Alliance. (n.d.). West African Lungfish. https://animals.sandiegozoo.org/animals/west-african-lungfish