Some fish, like the mudskipper, are able to walk on land thanks to their ability to breathe both in water and in air. Their modified pectoral fins allow them to move on land surfaces.
Originally, fish fins primarily serve to swim, stabilize their bodies, and navigate underwater. However, in some species, these fins have gradually changed, evolving into true supporting structures. The transformation of bones and muscles has allowed certain fins to become more robust, thicker, and articulated. As a result, they support the body's weight out of the water, somewhat like rudimentary legs. This greatly facilitates life when crossing short terrestrial spaces to find food or move to other bodies of water in case of drying out, a situation very practical for survival. It is these very specific anatomical changes that have allowed certain fish like the mudskipper or the axolotl to move out of the water, thus laying the evolutionary foundations for future tetrapods, our very distant ancestors.
To get out of the water, breathing becomes quite a challenge. Over the course of evolution, some fish have developed respiratory organs capable of extracting oxygen directly from the air. For example, species like the gobies or the lungfish (also known as the lung fish) use a system similar to a very rudimentary lung. At the surface, they inhale air, trap it for a moment in these modified organs, and absorb the necessary oxygen.
Other fish use their skin to breathe out of water, as long as it remains moist. Their skin then has a dense network of blood vessels, allowing for gas exchange directly with the surrounding air. This adaptation is not just practical; it is vital: in oxygen-poor water, having an organ capable of breathing free air gives them a real advantage!
Some fish temporarily come out of the water because they clearly find an ecological or dietary interest there. Essentially, when their aquatic habitat becomes low in oxygen or food starts to run low, they must explore elsewhere. On land, they can hunt small insects or take advantage of other food resources that they cannot find underwater. It's somewhat of a clever survival strategy. These fish then develop adaptations that allow for rudimentary terrestrial locomotion, just effective enough to explore the nearby terrestrial environment. No miracle: walking on land simply gives them access to a richer pantry or vital options when aquatic conditions are no longer favorable.
Transitioning from an aquatic environment to a terrestrial one is far from easy for a fish. Yet, some finned organisms did it about 375 million years ago. Species like Tiktaalik exemplify this gradual change: half fish, half tetrapod, this creature already had somewhat strengthened fins capable of supporting at least some of its weight out of water. Over time, these structures continued to evolve into true supporting limbs. Why did this transition occur? Because the terrestrial environment offered available spaces, fewer predators, and more food: the perfect plan for a successful escape from water. This transition represents a key moment in understanding how aquatic life could lead to terrestrial organisms.
The Tiktaalik, a species that is now extinct, is often regarded as a crucial evolutionary link. It had both typical characteristics of fish and terrestrial animals, thus revealing a critical stage in the transition of life from water to land.
The anabas, or climbing fish, can survive out of water for up to six days thanks to a special respiratory organ called a labyrinth, which allows it to extract oxygen from the surrounding air.
Some species of African lungfish can survive drought by burying themselves deep in the mud and breathing air through their primitive lungs for periods of up to 4 years!
The mudskipper, a fish that lives in mangroves, is capable of breathing through its moist skin and can spend several hours out of water, moving by hopping with the help of its adapted fins.
Sure! Here’s the translation: "Yes, by studying these fish, scientists can understand how the first terrestrial vertebrates evolved from aquatic forms. These current fish provide valuable clues about how evolutionary transitions between aquatic and terrestrial environments occurred."
Fish capable of walking generally prefer intermediate habitats such as mangroves, peatlands, or swamps, where fresh or brackish water coexists with dry land. These semi-aquatic environments facilitate their amphibious way of life.
Among the fish capable of walking are the mudskipper, the walking catfish (Clarias batrachus), and certain species of gobies. Their ability to walk is related to specific adaptations such as strengthened fins, which can support their weight on solid ground.
Yes, some walking fish have physiological adaptations that allow them to breathe outside of water. These adaptations may include modified gills, specialized skin, or even primitive lungs, enabling them to breathe air directly.
The terrestrial walk offers certain ecological advantages to these fish. Among these advantages are a greater food diversity, the ability to avoid aquatic predators, and the opportunity to conquer new environments when their initial habitat becomes less favorable or experiences seasonal variations.
No one has answered this quiz yet, be the first!' :-)
Question 1/5
