Monday, September 17, 2012

Predator/Prey Relationships in Miocene Spain

Joint American and Spanish Team Study Teeth to find out what Sabre-Toothed Cats Ate

A ratio of Carbon 12 to Carbon 13 isotopes preserved in the fossilised teeth of apex predators and herbivores that lived over nine million years ago has provided a joint American and Spanish research team with an insight into how food chains worked in the latter part of the Miocene epoch. The study, the academic paper having been published in the scientific journal "The Proceedings of the Royal Society of Biology", focused on the diets of the top, predatory mammals and attempted to establish how large carnivores such as Sabre-Toothed Cats and Bear Dogs (Amphicyonids) were able to live in the same habitats without necessarily competing for the same food resources.

Miocene Fossil Locations of Central Spain

Palaeontologists from the Museo Nacional de Ciencias Naturales (Madrid) and the University of Michigan (United States) studied the fossilised teeth of specimens of animals that had been found at a number of fossil dig sites at Cerro de los Batallones, just 25 miles south-west of Madrid. A substantial number of vertebrate skeletons have been discovered in this area, two dig sites are particularly rich in predator fossil bones. Scientists suspect these sites represent "natural predator traps", a herbivore may have become stuck fast in mud and this then attracted a number of carnivores and scavengers to the location hoping to feed on the hapless plant-eater. The meat-eaters soon became stuck too, and the rising pile of corpses would have attracted more and more predators, thus the number of carnivore fossil specimens found at such sites are far in excess of the number of herbivore fossil specimens found. Fossils found include those of hyenas, martens and skunks.

Two Types Sabre-Toothed Cat Studied

The researchers studied two species of Sabre-Tooth Cat, Promegantereon ogygia, about the size of an African Leopard (Panthero pardus pardus) and the much larger and heavier Machairodus aphanistus, which was about the size of an extant African Lion (Panthero leo). It is quite common to hear people describe Sabre-Toothed Cats as "Sabre-Toothed Tigers", this is an inaccurate description, as although Sabre-Tooths do belong to the same taxonomic family as today's "Big Cats" - Felidae, Sabre-Tooth Cats are not closely related to Tigers.

The Fearsome Bear Dogs

The other type of apex predator the research team studied was the Bear Dog known as Magericyon anceps. Bear Dogs are neither Bears or Dogs but seem to be distantly related to both types of carnivore, sharing a common Vulpavine ancestor. M. anceps was a particularly large and powerful example of the Mid to Late Miocene Bear Dogs, large specimens could weigh over 200 kilogrammes and would have stood over a metre high at the shoulder.

Apex Predators Co-existing

The study of the tooth isotopes revealed that the Sabre-Toothed Cats shared the same woodland habitat. The smaller Sabre-Tooth Cat species probably used the abundant cover to avoid encounters with M. aphanistus. Sabre-Toothed Cats have a different build when compared to modern cats. They are not built for speed but have immensely strong front legs and shoulders. Scientists have speculated that Sabre-Toothed Cats specialised in being ambush predators rather than pursuit predators, chasing after their prey. The woodland habitat would have been ideal for ambushing herbivores.

Sabre-Toothed Cats - Likely Ambush Hunters

Both species of Sabre-Toothed Cat showed no statistical differences in the ratio of Carbon 12 to Carbon 13 in their teeth samples. This means that they probably fed on similar prey animals that lived in the woodlands, but their body sizes probably meant that they targeted different sized prey. They may also have avoided direct competition by hunting at different times of the day. It has been speculated that Promegantereon ogygia may have hunted after dusk, or spent more time in the trees, so as to avoid the attentions of larger types of Sabre-Tooth Cat in the area. It seems that the members of the Machairodontinae living in the area that was to become central Spain preferred to eat primitive horses, animals that were not yet the highly efficient runners seen on race tracks today.

Bear Dogs "Top Dog" on the Open Plains

The tests on the Bear Dog teeth showed a different ratio, indicating that a different type of prey was preferred by these carnivores. The Bear Dogs hunted animals that lived in more open, grassland habitats, they seem to have been better suited to pursuit predation, tackling herbivores that lived in open areas such as antelopes.

It seems that nine million years ago, a number of mammalian apex predators were able to co-exist in this part of Europe as they seem to have specialised in hunting different types of prey animal.

Providing an Insight into an Ancient Miocene Ecosystem

Commenting on the study one of the researchers stated that such investigations using isotope analysis of fossil teeth provided an insight into the diets of long extinct creatures. This in turn gave the palaeontologists an understanding of an ancient, long extinct ecosystem.

Everything Dinosaur is a company run by parents, teachers and real dinosaur experts. It specialises in developing educational dinosaur toys, models, clothing and games and strives to help young people learn more about science through their fascination with prehistoric animals. Many of the items featured on the Everything Dinosaur website Everything Dinosaur have been designed and tested by the teachers and real dinosaur experts in the company.

To learn more about the products and services we offer at Everything Dinosaur click on our website links.

Our aim is to help young people learn more about Earth sciences through their fascination with dinosaurs and other prehistoric animals. Team members are happy to provide advice and support supplying free quizzes, drawing materials, puzzles, games even recipes for dinosaur themed biscuits and birthday cakes. With something like 900 products on line including dinosaur party supplies, Everything Dinosaur has built up a strong reputation assisting parents, guardians and fellow teachers, helping young people to learn more about science through creative play.

No comments:

Post a Comment