The pain of other living things is seldom humanly felt, their interests seldom considered, their intrinsic values discounted. Carl Safina, Yale Climate 360
A new study out of Australia has found that shape-shifting animal appendages such as beaks, ears, and tails are occurring in some species as a response to our increasingly warming world. Researchers found that the change in the appendage of these study species is increasing in size. The pattern of the changes is widespread and reveals that heating “may result in fundamental changes to animal form.”
In many parts of the earth, humans survive in a Goldilocks Zone of habitability where temperatures are not either too hot or cold for liquid water to be present. We can find examples in Afghanistan, Pakistan, and the Middle East.
We are a species that can’t evolve quickly enough to exist in temperatures out of the Goldilocks zone. We have the physical mobility to move poleward, of course. Still, very few migrants will cross national borders as walls are erected to keep people out from the United States southern border to Turkey building a wall along Iran’s border, to stop Afghani refugees fleeing political crisis and climate change.
Many species are and will be going extinct because they can’t move outside of their climate niche in time.
Of course, there are many factors to extinction besides climate change. Loss of habitat is the number one threat for most species. Reef colonies will die because of acidifying oceans, and rhinoceros and elephants are being hunted to extinction.
The authors of the study, writing in The Conversation, note that appendages are used to control internal temperatures. They provide examples by writing that African elephants, for example, pump warm blood to their large ears, which they then flap to disperse heat. The beaks of birds perform a similar function – blood flow can be diverted to the bill when the bird is hot.” This means the advantage to species that can evolve in time will help them respond to global heating.
Sara Ryding and Matthew Symonds write:
We found most documented examples of shape-shifting involve birds – specifically, increases in beak size.
This includes several species of Australian parrots. Studies show the beak size of gang-gang cockatoos and red-rumped parrots has increased by between 4% and 10% since since 1871.
Mammal appendages are also increasing in size. For example, in the masked shrew, tail and leg length have increased significantly since 1950. And in the great roundleaf bat, wing size increased by 1.64% over the same period.
The variety of examples indicates shape-shifting is happening in different types of appendages and in a variety of animals, in many parts of the world. But more studies are needed to determine which kinds of animals are most affected.
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Of course, animal appendages have uses far beyond regulating body temperature. This means scientists have sometimes focused on other reasons that might explain changes in animal body shape.
For example, studies have shown the average beak size of the Galapagos medium ground finch has changed over time in response to seed size, which is in turn influenced by rainfall. Our research examined previously collected data to determine if temperature also influenced changes in beak size of these finches.
These data do demonstrate rainfall (and, by extension, seed size) determines beak size. After drier summers, survival of small-beaked birds was reduced.
But we found clear evidence that birds with smaller beaks are also less likely to survive hotter summers. This effect on survival was stronger than that observed with rainfall. This tells us the role of temperature may be as important as other uses of appendages, such as feeding, in driving changes in appendage size.