Giant Ibex lived in the Southern Pyrenees after the Ice Age

The sub-species of the Iberian mountain goat Capra pyrenaica pyrenaica became extinct in the year 2000 before its biological and phytogenetic characteristics could be explored in depth. A new study has shed light on their size, origin and post-Ice environmental conditions after discovering three skull fossils from between 4,000 and 7,000 years ago in the southwest of the Pyrenees. 

Reconstruction of Capra pyrenaica pyrenaica that lived 7.000 years ago (left) and a modern ibex extinct in the year 2000 (right) [Credit: SINC/José Antonio Peñas]

In 1984 and 1994 during routine explorations the Speleological Group of Estella (Navarra) and Pedraforca (Barcelona) found the bone remains of two male and one female Ibex in the Karstic caves and wells that acted like traps in Larra (Navarra) and Millaris (Huesca). Both locations lie at 2,390 and 2,500 metres height, respectively. Up until now few fossils of this species (Capra pyrenaica pyrenaica) had been discovered in these areas. 

Ricardo García-González, researcher at the Pyrenean Institute of Ecology (PIE-CSIC) has been put in charge of analysing the skulls and comparing their craniometric characteristics with both fossil and modern day neighbouring mountain goat populations. 

Published in the 'Comptes Rendus Palevol' journal, the results suggest that these wild goats were 50% bigger than modern Ibex that lived in the Iberian Peninsula until it became extinct from the Pyrenees in the year 2000. 

"The skulls of the males where extraordinarily big in comparison with the other goat remains of the late Pleistocene Age (between 120,000 and 11,000 years ago) on South-West Europe," as explained by García-González. 

According to the study's only author, the increase in size could be due to the increased availability of trophic resources during the Holocene Age (present day dating back to 11,000 years ago). This would fit in with the widespread theory on ungulate evolution put forward by the scientist V. Geist in 1987, which makes reference to the "giants of the Ice Age." 

Males with enormous horns 

Some of these 'giants', such as the Megaceros deer, had large "display organs" which served to dissuade competitors and reduce the number of fights in an age when species were finding new opportunities and more food around the edges of glaciers. 

García-González outlines that "the males with large horns were more successful in terms of reproduction as a result. The females invested their energy into the survival of their offspring and so had no need to have bigger display organs." 

Along with their size, the high altitude at which the remains were found is unusual. The explanation lies in the fact that some 7,000 years ago the ice had begun to melt in Millaris (Ordesa National Park in the Pyrenees) at an altitude of 2,500 metres, where the remains of the last Pyrenees glaciers are still present. 

The researcher commented that "nutritious alpine pastures had already begun to develop up beyond the forest edges. The Ibex would take advantage of this in the summer with their seasonal migration, just like their modern counterparts." 

The origin of the subspecies in doubt 

As for the origin of the subspecies, the analysis of this wild Pyrenees goat's fossil skull falls in line with the molecular genetics studies and suggests an even greater similarity with the Alpine Ibex (Capra ibex). 

However, until now the scientific community thought that the Iberian mountain goat came from a common ancestor that it shared with the West Caucasian tur (Capra caucasica) that migrated towards the Central Massif of France around 80,000 years ago. 

"More findings and further fossil studies are required to confirm the origin and differences of this subspecies," concludes García-González. 

Source: Plataforma SINC via AlphaGalileo [June 21, 2012]