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Palaeobiology


Homeothermy

Hair belonging to a multituberculate was found in the fossilified faeces of carnivorous mammals. This shows that the multituberculates, like all living mammals, had hair to keep them warm, so they were warm-blooded.

Diet

This area is still debated. None of the fossils have been preserved well enough to show the stomach content. Based on the teeth and what the bones tell us about the chewing muscles, it was originally suggested that the multituberculates were herbivorous, eating tough vegetation like leaves. This was challenged because of the small size of the multituberculates: they would spend more energy dealing with tough nutrient-poor leaves than they would gain from those leaves. Bigger animals can develop a larger, more efficient gut to deal with leaves, but multituberculates were too small to have survived on a strict leaf-eating diet. They are now thought to have been omnivores, eating seeds, nuts and fruits as well as vegetation.

Lifestyle

The brain was reconstructed by looking at the cavity where it would have been in the skull. The structure of the brain, which showed enlarged lobes associated with smell, as well as the large inner ear region, both indicate that the multituberculates had an acute sense of smell and acute hearing. The strong development of these senses could indicate a nocturnal lifestyle. The fact that their eyes are big supports this: they would have needed larger eyes to see in the reduced light.

Multituberculates may have lived in trees; their long tail could have been used to grip branches, and the high mobility of their feet is like that seen in modern animals which go down trees head-first. The Asian multituberculates may have been more terrestrial and moved around in jumps.

Reproduction

The pelvis is narrow and is completely fused, which means that when giving birth the two sides of the pelvis could not be pushed apart. The young, therefore, would have had to go through a very narrow gap. The multituberculates do not possess the structures seen in monotremes which allows them to lay eggs, so multituberculates probably gave birth to live young. The young would have been very small and underdeveloped, like those of marsupials at birth.
Reconstruction of Ptilodus in headfirst descent
Reconstruction of Ptilodus going down a tree trunk head first.
(from Krause, 1983)
Click on image to enlarge.



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Author: Aude Caromel
Last updated: 20/11/06
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Websites produced by students on the MSc Palaeobiology programme in the Department of Earth Sciences at the University of Bristol for academic year 2006-7