Energy costs and savings of arboreal locomotion in great apes: measuring a tractable model species, homo sapiens

In recent years researchers have discovered a great deal about the way in which animals move around on flat ground yet little is known about how animals move in complex habitats. The most structurally complex environment on land must be the canopy of tropical rainforests, which presents a three-dimensional meshwork containing unpredictable changes in the continuity and nature of the supports available for locomotion. In this habitat, tree-living animals such as primates must cope with two problems in particular that rarely exist for animals that locomote on the ground: gaps in the canopy and the flexibility (compliance) of the vegetation supports against which they must exert forces to support or propel themselves. These problems are particularly prominent for the large bodied great apes, such as chimpanzees and orang-utans. Yet the problems of obtaining direct measures of energy expenditure of primates in the wild have to date limited understanding of the energetic cost of navigating these complex habitats.

In this project professional parkour athletes, who have elite gymnastic abilities, will serve as human models traversing custom-made, simulated jungle terrain. Their consumption of oxygen (a standard method for measuring energy expenditure in the laboratory) and their heat production will be measured. This will allow us to address our two aims:

1) to understand how the relative costs of demanding forms of arboreal locomotion for large-bodied great apes are affected by size and build, the details of the environment being traversed, and knowledge of the route being taken

2) to trial the use of thermal-imaging cameras to ascertain whether measures of the heat given off by the body represent a potentially viable method for estimating energy expenditure during complex locomotion in large-bodied apes in the wild.

Enhanced by its presence in blockbuster films and television advertising, parkour is a rapidly developing sport that has recently caught the public eye. It provides an excellent medium through which to communicate the findings of the study. For example, the agility of parkour practitioners bridges the perceived boundaries between primate arboreal locomotion and human terrestrial locomotion, providing a dramatic visual demonstration of the close links that humans have with their evolutionary cousins.

Several user groups are likely to benefit from the project findings. The general public, including school children, will learn about great ape ecology and our ancestral heritage. Our results are relevant to the welfare of captive great apes due to the considerable need to increase levels of physical activity to aid physical and psychological wellbeing. By studying which behaviours are the most energetically expensive, we can feed similar locomotor supports and arboreal routes into enclosure design. Finally, testing and developing physical capability is an inherent component of the Parkour athletic discipline and we will produce a document for Parkour Generations that presents the data in a format they can use to inform their training. For example, providing information on how energetic costs change over time with familiarity to a course and how energetic costs are affected by different types of activity on surfaces of differing compliance.

Beyond that academic beneficiaries described above, four user groups will benefit from the project and its findings: school groups, the general public, zoos and related organisations, and the parkour community.

School Groups and the General Public
Attracting attention through the highly visual and engaging medium of parkour, our findings will have the potential to generate interest among school students and adults alike about great ape ecology and their close links with humans, i.e. our ancestral heritage. The data once disseminated will also provide a greater understanding of how terrain, body shape, and experience effect the energy costs of locomotion, which can be valuable information for a range of users, from the lay person seeking to get fit to the professional athlete seeking to further enhance their capacity.

Zoos and Related Organisations
A better understanding of the costs of energetically expensive components of great ape locomotion will help us to select appropriate geographical areas for reintroduction programmes and to design training schemes for rehabilitant animals. Indeed, there is considerable need to increase levels of physical activity for many captive apes to aid both physical and psychological wellbeing. By studying which behaviours are the most energetically expensive, we can feed similar locomotor supports and arboreal routes into enclosure designs at zoos. This should inform improved captive animal enrichment.

The Parkour Community
Parkour athletes, both amateur and professional, are interested in testing and developing their physical capability; this is inherent in their discipline. From the proposed study, Parkour Generations will obtain data that informs their training: information on how energetic costs change over time with familiarity to a course, and how energetic costs are affected by different types of activity on surfaces of differing compliance. Parkour Generations reach many present and potentially aspiring users of parkour, who will obtain a greater understanding of the energetics associated with their discipline.


Timetable
A website, including visuals and written for the lay person, will be created at the start of the project in August 2011 with updates as the project progresses. The wider public including children will start to benefit within months of the project end, i.e. by 2012, once data are analysed. Zoos will also receive relevant information in 2012.

Skills development
The project represents a new collaboration and brings together a set of methodologies that none of the project partners presently has complete mastery of. Thus all collaborators will be exposed to new techniques to at least some degree. The PDRA will also be exposed to, we anticipate, many methods and situations of disseminating science to the public since this project should raise considerable interest. Thus the communication skills of the PDRA, and indeed the rest of the team, will be developed during and after the proposed project.