Myotragus, an extinct goat that lived on a desolate Mediterranean island, has been survived for millions of years by reducing in size and becoming cold-blooded, and it is a trait previously unknown in mammals.
Myotragus balearicus was a goat that existed on Spanish island which now is known as Majorca. Scientists were baffled as to how the goats had survived for so long on the island, which had little food and no means for them to escape. The extinct goat survived by altering its growth rate and metabolism to meet the available diet, becoming cold-blooded like reptiles, according to a recently released study report (Edwards, 2009). Ectotherms, on the other hand, develop slowly and can adjust their growth rates when resources change, making them ideal for resource-poor islands.
Paleontologists compared Myotragus bones with some reptilian bones that lived in the same region and at the same period and found that there were some features in common for both. Warm-blooded animals’ bones reveal an unbroken pattern of rapid development., Cold-blooded species’ bones have parallel growth lines that indicate interrupted development according to growth cycles, whereas warm-blooded animals’ bones have parallel growth lines that indicate interrupted development according to growth cycles, similar to the rings found on tree trunks. Warm-blooded organisms must have food at all times, thus their development and metabolic rates are controlled to match the amount of food available in the environment. The Myotragus bones have the same irregular development pattern as reptiles’ bones. In a paper published in the Proceedings of the National Academy of Science, Kohler and Moya-Sola wrote, “The bone microstructure indicates that Myotragus grew unlike any other mammal but similar to crocodiles at slow and flexible rates, ceased growth periodically and attained [physical] maturity extremely late by 12 years.”
These Myotragus species are the first mammals to reach the same level of flexibility and, as a result, survival as reptiles. Their brain is half the size of a typical even-toed ungulates animal also known as hoofed mammals and their eyes are also third the size of their own. This results in conserving the energy, because of those features.
The adults were around 18 inches (45 cm) tall and a little bit less than a size of a normally gown dog, while the young were around the size of a giant rat. It has taken a long time for Myotragus to reach maturity. The goats would have walked slowly to preserve energy, according to paleobiologist Meike Kohler of the Autonomous University of Barcelona, and would have spent a lot of time lounging about basking in the sun. The goat’s postcranial structure showed it couldn’t jump, run, or move quickly, making it easy prey.
These creatures existed for at least five million years ago. Myotragus’ reptile-like physiological and life history features were undoubtedly critical to their survival on a tiny island for 5.2 million years, more than double the typical continental species’ durability. But once humans discovered the island, they must have hunted them as per their meal and which is possibly not longer than 3000 years ago.
Edwards, L., 2009. Extinct goat was cold-blooded. [Online]
Available at: https://phys.org/news/2009-11-extinct-goat-cold-blooded.html
[Accessed 03 06 2021].