Why did penguins stop flying?
Scientists may have figured out why penguins lost the ability to fly.According to a new study, getting off the ground took too much effort for birds that were becoming expert swimmers.
Some aspects of penguins' life might be made easier by flight.The march of the emperor penguins might take a few easy hours rather than many deadly days.It would be easier to escape leopard seals at the water's edge if penguins could take flight.
The theory suggests that the birds' once-flight-adapted wings became more and more efficient for swimming and eventually lost their ability to get penguins off the ground.
More efficient diving made it easier to find food at depth.A modern emperor penguin can hold its breath for 20 minutes and then dive to 1,500 feet to eat.It was the first human contact with the large emperor penguin colony.
This theory is supported by the new study of energy costs in birds that fly and dive.
There are tradeoffs between movement in a second medium and form in wild animals, according to the study co-author.
Good flippers don't fly very well.The giant prehistoric penguins were revealed.
The murre uses its wings for diving, but also flies.It may resemble the last flying penguin ancestors, according to scientists.
Swimming birds propel themselves through the water with their feet.The ancient penguin ancestor that was the last of its line to take flight can be considered a model for the lifestyle energy use of these birds.
Today's penguins are grounded because of the analysis of how guillemots burn energy.Guillemots are bested in diving by penguins, according to the study.
Flight costs them more energy than any other bird and is difficult to maintain.
The team looked at thick-billed murres at a colony in Canada.To mark the physical costs of their activities, they injected the birds with stable oxygen and hydrogen.The team fitted them with time-budget devices that record movements, speeds, and other data like pedometers do.
Birds only do three things: sit, swim, and fly.John Speakman, who leads the Energetics Research Group at the University of Aberdeen, said that it is possible to calculate how much each component of the budget costs by measuring lots of birds and combining their time budgets with the total costs of living from the isotope measures.
The reduction in wing size would make diving more efficient and flying less so.Lighter bones that make it easier for birds to fly gave way to more dense bones, which may have made them less dense for diving.Speakman thinks the wing changes were the primary adaptation.
The results make a lot of sense, according to University of Texas at Austin's Julia Clarke, who studies bird evolution and how the flight stroke was co-opted for underwater diving.
There are different scenarios explored for the origin of penguins.A key step in the wing-to-flipper transition is explained by new findings from other diving birds.
The work indicates an important reason why penguins stopped flying and evolved larger body sizes, according to a behavioral ecologist at the University of Tokyo's Ocean Research Institute and a National Geographic Society Emerging Explorer.
The little penguin, which is less than a pound in weight, is an interesting example.Little penguins cannot survive against the murre, which can dive and fly, because of the dive cost.
Bigger bodies allow for longer dives, which may be why rapid evolution produced so many bigger-bodied penguins soon after the animals lost the ability to fly.
Chris Thaxter is a seabird ecologist with the British Trust for Ornithology.
When wings are used above and below water, there may be an evolutionary tipping point beyond which flight is too costly and unsustainable.The study was published in the May 20 edition of the journal.
The earliest known penguin is 60 million years old, but scientists don't have fossils of flighted penguins.