Human perception of any phenomenon is often full of stereotypes as a vast amount of information we learn indirectly, even without making any effort. For example, a mistake could be made if we assume that birds must only be associated with air and fish only with water. Probably, there is no stereotype about mammals, although it definitely should be mentioned that bats, whales and, in fact, people are all mammals.

So, let’s debunk the stereotype regarding fish: mudskippers can survive on land and it is believed that they spend most of their life on it.


The mudskippers (Periophthalmus)

To moisten their eyes on the land they roll their eyes into special sockets, what is quite unusual for fish.


Eyes moistening

Also, lungfishes can live on land without any problems. There are only six species of this fish left. It is interesting that the young lungfish breathe almost exclusively with gills, but as they age they switch to their lungs.


The West African lungfish (Protopterus annectens)

The flying fish can fly up to a height of five meters and can glide up to 400 meters. They have little control over their flight, often getting on board of the ships. There was even a reported case of a man who was knocked off his feet on a deck.


The flying fish (Exocoetidae)

In addition to the flying fish other biological classes of animals also mastered the flight. Traditionally, the ability to fly is associated solely with birds, but much more unusual and interesting creatures were able to fly before.

An important thing should be noted: not all flying creatures are birds and not all birds are flying creatures.

Nowadays there are birds capable of underwater hunting. Penguins are the most obvious example here. They are strictly flightless birds, but some species are able to dive to depths of up to 200 meters.


The king penguin (Aptenodytes patagonicus)

Far more skillful swimmers existed in the history of the Earth’s fauna. About a hundred million years ago underwater hunting was done by hesperornis. These birds had very small wings but powerful legs.

Also, hesperornis had teeth, primarily in the lower jaw while in the upper part there were special pits for the lower teeth. The early ideas about standing on the shore hesperornis are most likely false. Their feet allowed them to move well under water, but it is likely that they could only crawl on land.


Hesperornis underwater (Hesperornis regalis)

The largest flying creatures were pterosaurs. They, in turn, are reptiles or tetrapods, which makes them similar to dinosaurs and their modern representatives: crocodiles, lizards, and snakes.

One of the largest pterosaurs was quetzalcoatlus, named after the Aztec god. It is believed that this pterosaur could weigh a whole quarter of a ton, and its wingspan was up to twelve meters.


Quetzalcoatl vs. Tezcatlipoca, XV century


The quetzalcoatlus (Quetzalcoatlus northropi)


A model of the quetzalcoatl in the Saurian game

The gigantism of the animals was caused by several factors. At first, dinosaurs grew very quickly, since in this case, the chances of survival were much greater. It is also known that reptiles don’t care much for their offspring, only some species protect the newly hatched children. And snakes have even the phenomenon of infanticide when the newly born snakes must already run away from the first threat — their own mother. Secondly, there is a phenomenon of the “island gigantism” in which animals reach enormous sizes in the absence of predators. Although “island gigantism” affects mostly rodents, birds, and plants, while predatory animals on islands become smaller.

Therefore, the gigantism of the ancient animals can be justified by the high level of carbon dioxide in the Earth’s atmosphere, which allowed the “greening” of the planet and this, in turn, gave the dinosaurs an almost endless food supply. The sharp increase in the number of herbivorous dinosaurs also gave a growth boost to the number of predators.

Maximum Wingspan

The size of a bird can be rated by its wingspan. So, the wandering albatross have the largest wingspan among the living flying creatures.


The wandering albatross (Diomedea exulans)

But not a bird had the largest wingspan in the history of the Earth, although some extinct bird’s wingspan reached 5 to 7 meters. The largest flying birds in history were the argentavis and the pelagornis.


The pelagornis (Pelagornis sandersi)

Much larger sizes could reach the pterosaurs — the flying reptiles.


Wingspan comparison of the pterosaurs and birds

Thus, one of the largest wingspan animals were the arambourgiania, the quetzalcoatl, and the hatzegopteryx. But it is worth noting that the information about the wingspan of the arambourgiania varies from 7 to 13 meters, while the dimensions of the quetzalcoatl and the hatzegopteryx are more accurate and definite.

Maximum Weight

There are also flightless creatures among the biological class of birds. We can recall the ostrich or the cassowary which are quite large and flightless birds. Or the penguin who gave up its flying skill but gained the ability to stay long underwater.

The most dangerous bird of our time is the cassowary.


The cassowary (Casuarius unappendiculatus)

This bird can kill an adult. But even it is not the biggest bird that existed on the Earth.


A comparison of the weight of the pterosaurs, flying and flightless birds

Thus, the dromornis and the aepyornis birds were much heavier than one of the largest pterosaur the quetzalcoatl and reached half a ton of weight. Unlike the latter, they were flightless.

It can be concluded that with the current parameters of our planet, the designated radius, and the force of gravity, the maximum weight of an animal that is able to fly can reach 250 kilograms. Though, it is possible that this is not the limit.


The dromornis (Dromornis stirtoni)