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Could Flying Reptiles Really Skim the Water to Catch Fish – The Evidence Reviewed

Could Pterosaurs really use Water Skimming Techniques to catch Fish?

The Pterosaurs are an extinct group of flying reptiles, sometimes mistakenly referred to as Pterodactyls. They evolved in the Triassic and dominated life in the air until the emergence of the birds some sixty million years later. The last of the Pterosaurs, some of which were the largest flying creatures known to science, died out at the very end of the age of reptiles, some sixty-five million years ago at the end of the Cretaceous geological period.

Many Pterosaurs were Fish-Eaters

Almost since the first Pterosaur fossils were studied closely; scientists have speculated about how good they were at flying and how these flying reptiles might have fed. Since many Pterosaur fossils have been found in coastal or marine deposits it is believed that many were piscivores (fish-eaters). The teeth in many primitive Pterodactyloids such as Criorhynchus and Rhamphorhynchoids like Eudimorphodon seem well suited for grabbing and holding slippery fish. The dentition supports the theory that these animals fed on fish, but how these animals actually captured fish remains a bit of a mystery.

How did Flying Reptiles Catch Fish?

It had been thought that some Pterosaurs used fishing techniques similar to the black skimmer (Rhynchops niger), a tern-like sea bird from the Americas. This bird skims the surface water of lakes and lagoons with its lower mandible ploughing through the water. When a small fish is detected the bill snaps shut.

The lower mandible is larger than the top part of the bill and the skull and jaws are quite robust, able to withstand the stresses of this type of feeding behaviour. pomona tourist attractions

In the past, Pterosaurs were thought to be clumsy fliers, little able to do more than glide, but more recent studies have shown that these animals were accomplished fliers. For example, on the front of a Pterosaur’s long wrist bones (carpus) there was a small bone that curved back towards the shoulder. This is called the pteroid bone and is unique to Pterosaurs. At first, palaeontologists thought this to be the atrophied remains of a digit but this extension of bone is now thought to have supported a smaller flight membrane in front of the arm. This smaller wing-like structure in front of the main wing would have helped control the flow of air over the wing, thus controlling speed and altitude. This supports the view that these animals were sophisticated fliers, very much at home in their aerial environment.

Results from a series of experiments carried out by scientists show that up to twenty percent more power is required for the animal to keep flying straight when the jaw is immersed in water. As the models skimmed the water in this way, they produced drag which compromised their ability to fly and demanded more muscle activity to keep them airborne. This need for increased power for this type of flight may have prevented flying reptiles from hunting in this way. This evidence, coupled with close studies of Pterosaur skulls and jaws which do not show the expected modifications required such as thicker bones to cope with the stresses of this type of foraging makes a number of palaeontologists doubt whether Pterosaurs fed by skimming for fish like the black skimmer.

The role of the Pterosaur Crest

Perhaps Pterosaurs used their relatively keen eyesight to spot prey in the surface water and then swooped down on it plucking the fish out of the water. Jerking the head downwards to permit the jaws to enter the water may provide one of the reasons why many Pterosaurs developed complicated crests. These crests could have acted as aerial stabilisers as well as display items for courtship and to intimidate rivals. The Rhamphorhynchoids had their heyday in the Jurassic but were replaced with the long-necked Pterodactyloids by the Cretaceous. Perhaps the longer necked Pterodactyloids had an advantage when feeding by plucking fish from the sea.

Recently scientists at the University of Reading (UK) led by a number of prominent palaeontologists have studied the proposed feeding habits of Pterosaurs. Using models of the jaws of Pterosaurs and a black skimmer, these scientists set up a series of experiments to test whether Pterosaurs could use their lower jaws to plough through water hunting for fish

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