Body size variation in Quaternary mammals

Mammal body size during the Quaternary period varies between sites and over time. We are comparing ice age mammal species from the past 750,000 years in Britain to investigate the causes of this variation.

Current hypotheses to explain body size variation in ice age mammals include:

  • Temperature¬†
    Large animals are better adapted to cold periods as they conserve heat more effectively. Small animals are more able to lose heat during warm periods.
  • Vegetation
    The quality and quantity of vegetation determines herbivore body size, and therefore carnivore size.
  • Competition
    Body size is affected by the presence or absence of related, competitor species.

Project

We are studying mammal fossils to investigate the causes of body size variation. The specimens:

  • represent around 20 mammal species
  • include carnivores and herbivores
  • derive from some 50 sites across southern Britain
  • date from 750,000 to 10,000 years ago

Previous work on plant and mammal fossils has produced valuable resources for the study of body size variation, including:

  • a large database of mammal bone measurements for key Pleistocene sites in Britain
  • quantitative estimates of palaeo-temperatures and past vegetation
Research aims

Body mass is a fundamental parameter for understanding the adaptations, ecology and life-history of mammals. Our data are key in determining the effect of past climate change on individual species and community function.

The Quaternary is the most recent geological period, and many of the targeted mammal species are alive today. Our results will help to predict and understand the effects of current and future climate change on mammal fauna.

Methods

Palaeotemperature and vegetation

To estimate palaeoenvironmental conditions, we use:

  • data from associated invertebrate flora and fauna, such as beetles or ostracods
  • floral and faunal lists, using models based on modern distributions
  • associated pollen or plant macrofossil data, from which vegetation spectra are obtained and simple metrics such as degree of wooded cover can be derived
  • models produced by colleagues at the University of Bristol. Researchers at Durham University are using these to drive a vegetation model and produce estimates of productivity for different plant types
Determining body size variation

We are converting bone measurement data to body mass, using regression equations based on living species. A mean body mass for each species is obtained for each fossil site or horizon.

Mammal body masses are compared to palaeoenvironmental indices using a multivariate statistical approach. This should enable us to:

  • resolve the effects of temperature and vegetation on the body sizes of different mammal species
  • understand any effects of the mammals on each other
Project leader
Adrian Lister
Prof Adrian Lister

Researcher in the Vertebrates and Anthropology Palaeobiology Division, studying processes of evolution and extinction in Quaternary mammals.

Project staff

Dr Tom White
Post-doctoral researcher in palaeoenvironmental data, University of Oxford.

Photograph of myself sitting beside a glacial lake
Dr Angela Self

An entomologist researching the effects of climate change by studying Chironomidae.

Project collaborators

Prof Paul Valdes and Dr Joy Singarayer
University of Bristol

Dr Judy Allen and Dr Yvonne Collingham
Durham University

Dr Sarah Collinge
NERC

Mr Juha Saarinen
University of Helsinki

Glossary

Quaternary period
A geological period spanning approximately the last 2.6 million years.

Pleistocene epoch
A geological epoch within the Quaternary period, lasting from 2.6 million to around 11,700 years ago.