Tortoise Hatchlings Tend to Orient Towards Objects that Resemble Faces
Thu, April 22, 2021

Tortoise Hatchlings Tend to Orient Towards Objects that Resemble Faces



Tortoises generally have lifespans that are comparable to human beings although some have been known to have lived longer than 150 years. Even at diminishing levels and although they may not look busy, they play an important role in the ocean ecosystems by maintaining healthy coral reefs and seagrass beds. They also provide key habitat for other marine life, which helps facilitate nutrient cycling from water to land and balance marine food webs. Another recent finding is that freshly hatched tortoise tends to orient themselves toward objects that resemble faces. This is according to, citing authors Elisabetta Versace and colleagues.


Natural preference for faces

A trio of researchers from the University of Trento and the University of London said that just as newborn humans tend to orient to the face of their mother, other species of animals are also the same. Such kind of behavior is hereditary and is believed to be a part of bonding.

For their study, Versace and team test the possibility of face orienting in reptiles. So, they created a face-like structure by putting square black blocks into a white background. The image resembles the mouth, nose, and eyes. They also pasted the same blocks but in a different way (not resembling a face). Then, the team put 136 newly hatched tortoises in the vicinity of their creations and observed how they behaved. Results show that tortoise hatchlings tend to orient themselves towards faces, approximately 70% of the time, but showed no preference for other structures that did not resemble faces.



Tortoises as antisocial creatures

The team said that their finding is noteworthy since tortoise is known as antisocial creatures. From the time they were hatched, they avoid other tortoises and receive no care from their parents. They likewise don’t’ interact with other species. This is why their inclination towards objects that resemble face suggests that the behavior is a part of their genes. Previous studies highlight that modern tortoises appeared around 30 million years ago, which means that such kind of attraction may have existed in history. Perhaps, the behavior has evolved in the common ancestors of birds, reptiles, and mammals.

Dr. Versace said that the spontaneous attraction to faces has been observed in social animals, such as chicks, monkeys. It was also observed in humans. This is understandable since these species need parental care. Such early adaptation is important to help young animals respond to other members of the same species and their parents. Yet, now it shows that such kind of behavior is also found in solitary hatchlings and may have just evolved for another reason.

The team said that the tortoises in their study were hatched and kept away from any human or animal faces from birth until they started the test. They were carefully placed in the middle of a rectangular shape that is divided into four areas. Some contain a face-like stimulus while others control stimuli.

The ability to recognize and respond to cues linked with other living animals could help young animals acquire information that is necessary for their survival, said Gionata Stancher, Head of the Tortoise Sanctuary Sperimentarea.



Turtles in trouble

Tortoises are turtles but not all turtles are tortoises, according to Katie Gregory, a zookeeper at Nashville Zoo. She said that tortoises have more domed and rounded shells where turtles have more water-dynamic shells. Tortoises spend most of their time on land while turtles are adapted for a life spent in water. Tortoise is also often heavier and larger. Their elephantine hind legs help them move around and carry the extra weight. On the other hand, turtles have webbed feet or flipper-like legs so that it will be easier for them to cruise through the water.

Whit Gibbons, emeritus professor of ecology at the University of Georgia, however, told the National Geographic that several turtle species are now at risk of vanishing. The Yangtze giant softshell turtle, for instance, is now down to four individuals. The Northern River Terrapin males are also undergoing a dramatic color change in the breeding season and there are breeding programs initiated to help bring these species back from the brink of extinction. Both Gregory and Gibbons are not involved in the recent study.

Gibbons recognized the importance of turtles in our ecology. He said that they serve as the garbage patrol of an area, eating up dead fish from rivers and lakes. They do a lot of good and do not harm the environment.  the burrows that gopher tortoises dug can shelter 350 more species, including bobcats, rabbits, and burrowing owls. They also provide homes for critters. Their absence would be a psychological and cultural loss to societies, he added.


Taxon richness and endemism of tortoise

In a statistic provided by Anders G J Rhodin from the Chelonian Research Foundation and published by Research Gate, it listed turtle mega diversity countries based on total taxon richness (count of different species) and numbers of endemic (ecological state) taxa.  Based on total richness, the USA has 53 number of tortoise and freshwater species, 82 taxa. Mexico is the third-richest region with 42 species, 57 taxa. Some other countries mentioned include Colombia (28 species, 29 taxa), Ecuador (24 species, 24 taxa), Peru (15 species, 16 taxa), China (31 species, 31 taxa), India (28 species, 36 taxa), and Australia (25 species, 29 taxa).

The statistic also shows that the richest wilderness area for turtles, whether measured in endemic taxa, total taxa, or total species, is the deserts of North America. It is slightly richer than Amazonia, the next richest-wilderness area. The geographical isolation of water bodies in these deserts paved the way for the evolutionary radiation in the genera Kinosternon (mud turtles) and Trachemys (slider turtles).

Meanwhile, database company Statista shows the volume of illegal live turtle trade seizures globally, by source region. From 2005 to 2015, nearly 50% of live turtle seizures were from South-Eastern Asia, followed by Southern Asia (23%), Europe (10%), Central Asia (6%), and Northern Africa and West Africa (5%).

Behind tortoise’s chill demeanor, they are ecological shakers and movers. They move between ecosystems, such as the beach and the ocean. Dr. Versace and the team’s findings could be useful in understanding their health and conserving their populations.