Social secrets of fossils

2001/02/05 Galarraga Aiestaran, Ana - Elhuyar Zientzia

• Eboluzioa
• Paleontologia
• Arkeologia

Joel Berger of the University of Nevada and other colleagues from the United States and Mongolia have based their work on ungulates, i.e. deer, cows, horses, etc. Considering whether or not they live in groups of individuals of a single sex, these species present a wide range of social behaviors.

These differences manifest when the whole group dies at once (immersed in a swamp, fallen to an icy lake or trapped by a volcanic eruption). In this way, Berger explains that in a field of today disappeared species something like this occurred to them and, analyzing the organization of the group, we can deduce their behavior.

In some species of ungulates males and females are different in size and adage, which is known as sexual dimorphism. These species tend to live in single-parent groups, where males and females only meet when looking for partners. Therefore, victims of collective death are of one sex or another.

Thus, it seems logical to extrapolate from living beings to missing species and establish a relationship between sexual organization and dimorphism that appears in the footprints. However, other factors such as crossing a river in Serengeti National Park in Africa, young and vulnerable people will be more likely to die.

Is this model also valid for dinosaurs? Although to some extent it could be acceptable, since there are currently no living relatives and you cannot predict where to seek answers, it is very difficult to secure anything.

Peter Dodson of the University of Pennsylvania says dinosaurs also suffered collective deaths and believes that Bergers' work can help better interpret fossils.