A new paleoclimatic study conducted on a stalactite from the island of Flores, Indonesia, shows a marked decline in rainfall between 76,000 and 55,000 years ago, with a peak of aridity shortly before the disappearance of Homo floresiensisone of the most curious and well-known extinct human species, which lived between 700,000 and 50,000 years ago and is considered an example of insular dwarfism applied to a human species. Although its origin remains a matter of debate, new evidence suggests that the drastic climate changealong with the arrival of Homo sapienshas probably contributed to the extinction of these ancient cousins just over one meter tall.
An international research group, with leader Michael K. Gagan from the University of Canberra, recently published on Communications Earth & Environment a new study that could shed light on the disappearance of Homo floresiensis. The scholars carried out chemical analyzes on a stalactite from the Liang Luar cavenear the Liang Bua cavewhere the largest number of remains attributable to this hominid were found.
The chemical analysis on the stalactite made it possible to identify the mineral deposit and its isotope ratio over time, both of which vary depending on the seasonal intensity of precipitation. Through the variation of these parameters, it was possible to clearly distinguish between dry seasons and monsoon seasons, being able to estimate the amount of precipitation in a certain period of time.
The data collected by the research group regarding rainfall are very interesting: it is highlighted that there has been a constant decline in the amount of rainfall in a period that goes from 76,000 to 61,000 years ago. The maximum peak of aridity, with the minimum rainfall, would have been reached between 61,000 and 55,000 years agoshortly before the attestation of the last remains of Homo floresiensis of our knowledge.
This decrease in rainfall also finds correspondence in the archaeological data of the Liang Bua site. As regards the sediment layers referable to this long period, one can be noted progressive decrease in the quantity of remains associated with the attendance of the site: not only do the fossil remains of Homo floresiensisbut also and above all those of the animal that was probably its prey, that is Stegodon florensissort of extinct dwarf elephantalso an example of insular dwarfism.
Although it cannot be said with certainty that the extinction of Homo floresiensis and other endemic species of Flores was caused byaridification of their habitat, this must certainly have caused greater survival difficulties for the communities on the island. The criticality of the situation then appears evident, if we consider that starting from 60,000-50,000 years agoeven our species, Homo sapiensreached the islands of Southeast Asia, probably having, together with the climate, a concomitant role in the extinction of Homo floresiensis.
