Nocturnal animals first evolved to make noise so that they could communicate in the dark
The ability of animals to make vocal sounds began 200 million years ago because nocturnal animals had to communicate in the dark, scientists say.
The common ancestor of vertebrate animals on land, including mammals, birds and frogs, did not have the ability to communicate through vocalisations.
Instead, acoustic communication evolved separately in the last 100 million to 200 million years – depending on the group, American and Chinese researchers said.
Creatures that have since evolved – active during the day – during the day – carried this new ability to communicate acoustically via growls, chirping, and roaring.
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Birds, such as this marsh wren, rely heavily on acoustic communication to expand areas and attract partners
“Here we show that this idea of the development of signal-forming ecology applies for hundreds of millions of years and to fundamental types of signals, such as being able to communicate acoustically or not,” said study author Dr. John Wiens of the University from Arizona.
WHAT ARE VERTEBRATES?
Vertebrates include all animal species with backbone.
They include mammals, reptiles, birds, amphibians and fish.
Animals without vertebral columns are known as invertebrates.
These include insects, arachnids, squids and earthworms.
Vertebrates originated around 525 million years ago.
Dr. Wiens and his research partner, Zhuo Chen from Henan Normal University in China, have put together an evolutionary tree for 1,800 species of mammals, birds, lizards and snakes, turtles, crocodiles and amphibians that go back 350 million years.
The team collected data from scientific literature about the absence and presence of acoustic communication within each sampled species, mapped it on the tree and analyzed the data.
They discovered that the common ancestor of vertebrate land animals could not use vocalisations to communicate.
The study, published in Nature communication, also found that the origin of communication via sound is strongly associated with a nocturnal lifestyle.
This is due to the lack of light, which means that beings were bothered by the lack of visual signs and had to find other methods to communicate.
When light is no longer available to display visual signals such as color patterns to intimidate a competitor or attract a partner, sound transmission became the most effective means of communication.
But even beings in genera that switched from a nocturnal to a daily lifestyle retained their ability to communicate through sound – especially birds, which seem to make the most intense sound when the day breaks.
Frogs, such as mammals, originated as predominantly nocturnal animals, but remained able to communicate acoustically after being switched to being active during the day.
It is possible that this lively ‘morning choir’ that we knew so well from our lies on Saturday morning could be a remnant of their nocturnal ancestors.
“There seems to be an advantage to evolving acoustic communication when you are active at night, but not a disadvantage when you switch to being active during the day,” said Dr. Wiens.
“We have examples of acoustic communication that is kept in groups of frogs and mammals that have become daytime, even though both frogs and mammals became active at night hundreds of millions of years ago. “
The authors estimate that acoustic communication is present in more than two-thirds of terrestrial vertebrates.
The researchers also discovered that acoustic communication is a remarkably consistent evolutionary trait.
While some of the animal groups easily come to mind for their vocal talents – such as birds, frogs and mammals – crocodiles as well as a few turtles and turtles can ‘talk’.
Another finding was that the ability to “talk” does not seem to be the engine of diversification – the speed at which a gender develops into a new species – as some scientists believe.
Dr. Wiens illustrated this by pointing to birds and crocodiles.
Both lines have acoustic communication and date from around 100 million years ago.
But although there are nearly 10,000 bird species, the list of crocodilians does not extend beyond 25.
“If you look at a smaller scale, such as a few million years, and within certain groups such as frogs and birds, the idea works that acoustic communication encourages speciation,” he said.
“But here we look at 350 million years of evolution and acoustic communication does not seem to explain the patterns of species diversity that we see.”