One of the mysteries of science has been unexpectedly unveiled. Researchers found out what lies behind the ultrasonic hearing of whales and dolphins, and their way to the answer was paved by fossils.
Researchers from South Carolina discovered the fossilized ear of what they later identified as a prehistoric dolphin species on a drainage ditch. They haven’t encountered this species before. The recently discovered species is called Echovenator sandersi, and the fossilized fragment helps scientists study the way cetaceans used to communicate back in the day and how is it related to the way they do it now. In other words, what is the evolution of ultrasonic hearing?
Echolocation is also called biologic sonar, and it is the characteristic behavior of cetaceans: dolphins, whales, and sperm whales – all of them toothed species. Humans cannot perceive these high-frequency sounds. Echolocation is an important and extraordinary feature which helps some of the marine animals communicate and tracking others of their kind or food, and the ancient Echovenator sandersi possessed it. Moreover, the entire head skeleton was designed in such a fashion that the animal should be compatible with echolocation and ultrasonic hearing.
Scientists have submitted the fossil to various tests (among which CT), and these showed to them that the ultrasonic hearing is a feature of the very first whales. The Echovenator sandersi is a species that is supposed to have lived about 27 million years ago, which made researchers believe that the ultrasonic hearing accompanied whales in the early stages of their evolution.
Researchers also gathered more data on the Echovenator sandersi: it didn’t live in deep, salty waters, and it measures two meters (which made it a rather small animal, in comparison to other prehistorical beasts). The name he was given translates as “echo hunter”, which highlights its properties and its importance for the study.
The study was led by researcher Morgan Churchill, who comments the following:
“Echolocation is probably one of the most remarkable and unique adaptations within mammals. Out of 6,000 mammal species alive today, only bats and toothed whales, along with a very small number of small insectivores, use echolocation as a major way of navigating their environment.”
The results obtained by Morgan Churchill’s team have been published in Current Biology (journal).
Image source: Wikipedia