|The theropod resonating chamber from Jurassic Park III|
While this is science fiction it raises the interesting question as to what ancient creatures sounded like. A team of South American scientists has ascertained the vocal capabilities of a phorusrhacid, a species of terror bird which roamed the grasslands of South America until just a few million years ago.
The phorusrhacids were powerful predators, with some species growing up to three metres in height. Fast, and armed with a cleaver-like bill, they were the top predators in the South American grasslands until South America collided with North America, allowing sabre-toothed cats access to the south. This new study focused on the four foot, 3.5 million year old Llallawavis scagliai. The species was discovered only recently, but the type fossil is the most complete terror bird discovered. 90% of the skeleton was present including an exquisitely preserved skull.
|The 90% complete skeleton of the 3.5 million |
year old phorusrhacid Llallawavis scagliai
'The mean hearing estimated for this terror bird was below the average for living birds,' said Dr. Federico Degrange, lead author of the study from the Centro de Investigaciones en Ciencias de la Tierra, Argentina. 'This seems to indicate that Llallawavis may have had a narrow, low vocalization frequency range, presumably used for intraspecific acoustic communication or prey detection.'
This new understanding of the sensory capabilities shows why the phorusrhacids were successful for so many millions of years. Apart from a lack of other predators, their sensory capabilities were perfectly adapted to hunting and stalking prey. Llallawavis would not have preyed upon the same creatures as the larger species of terror bird, so different species may have had different vocal ranges dependent upon ecological conditions.