COMPLIANT INTERACTIONS AND LIMB MECHANICS DURING ARBOREAL LOCOMOTION IN TROPICAL FOREST ENVIRONMENTS
Lead Research Organisation:
University of Birmingham
Department Name: Sch of Biosciences
Abstract
Sumatran orangutans are the largest mammal to live an exclusively arboreal lifestyle and yet they habitually navigate the slender, peripheral branches of trees - the terminal branch niche - where the majority of tasty fruits and the narrowest gaps between tree crowns are situated. Theoretically they should access these slender branches either by suspending underneath them or walking on all fours on top with highly flexed joints to reduce branch vibrations. But contrary to these predictions we have shown that orangutans actually walk bipedally (that is, like humans) on the very smallest flexible branches, using their long prehensile toes to grip multiple supports and increase stability, while freeing one or both hands to reach fruits or other branches for gap crossing. Interestingly and unlike all other monkeys and apes tested to date (including chimpanzees and gorillas), orangutans maintain very straight legs when they walk bipedally in the trees. The benefits of this are unclear, but are important for 3 key reasons. Firstly, orangutans are an important model for the locomotor ecology of arboreal animals and the relationship between large body mass and the terminal branch niche. Secondly, arboreal bipedalism is increasingly thought to have been a fundamental component of the locomotor repertoire of the common ancestor of all apes and elucidating its ecology and mechanics will aid interpretation of the Miocene fossil record and the evolution of locomotor diversity in the living apes. Finally, increasing evidence suggests that the origins of human terrestrial bipedality lie in locomotion in an arboreal rather than terrestrial setting and studying the locomotor ecology and mechanics of arboreal bipedalism may shed light on the formative stages of the evolution of our own bipedality. The suggestion that bipedality evolved in the trees and has been present to some extent since the split from the old world monkeys is key to the distinction between the human and chimpanzee fossil record, since adaptations for bipedality have traditionally been taken to define human ancestors from those of the other African apes. In this proposal we combine studies of wild orangutans with those of zoo orangutans and humans to quantify the mechanics of arboreal bipedality, and crucially, how these change in accordance with changes in the mechanics of the branches, since branches taper and become more flexible towards the ends. It is possible that the straight legged postures might enable either transfer of energy between joints; or the transfer of energy from the flexible branches to the orangutan, in the same way as human athletes recover energy when running on springy running tracks. To study these we will use a relatively new technique in gait analysis, ultrasound, to record the behaviour of the muscles and tendons during locomotion in humans and orangutans. When merged with data on muscle activity and mechanics this will allow us to obtain a complete picture of internal and external energy storage and transfer during arboreal bipedality. We will also complement these data with computer modeling to mimic energy transfer from branches and between joints in situations that are not possible or practical to test experimentally.
People |
ORCID iD |
Susannah Thorpe (Principal Investigator) |
Publications
Thorpe Susannah K. S.
(2014)
The arboreal origins of human bipedalism
in ANTIQUITY
Halsey LG
(2016)
Bridging the gap: parkour athletes provide new insights into locomotion energetics of arboreal apes.
in Biology letters
Neufuss J
(2014)
Fibre type composition in the lumbar perivertebral muscles of primates: implications for the evolution of orthogrady in hominoids.
in Journal of anatomy
Myatt JP
(2011)
Hindlimb muscle architecture in non-human great apes and a comparison of methods for analysing inter-species variation.
in Journal of anatomy
Halsey LG
(2017)
Practice makes perfect: Performance optimisation in 'arboreal' parkour athletes illuminates the evolutionary ecology of great ape anatomy.
in Journal of human evolution
Roberts A
(2014)
Challenges to human uniqueness: bipedalism, birth and brains
in Journal of Zoology
Crompton RH
(2010)
Arboreality, terrestriality and bipedalism.
in Philosophical transactions of the Royal Society of London. Series B, Biological sciences
Van Casteren A
(2013)
Factors affecting the compliance and sway properties of tree branches used by the Sumatran orangutan (Pongo abelii).
in PloS one
Chappell J
(2015)
The Ontogeny of Gap Crossing Behaviour in Bornean Orangutans (Pongo pygmaeus wurmbii).
in PloS one
Van Casteren A
(2012)
Nest-building orangutans demonstrate engineering know-how to produce safe, comfortable beds
in Proceedings of the National Academy of Sciences
Thorpe SK
(2009)
Orangutans employ unique strategies to control branch flexibility.
in Proceedings of the National Academy of Sciences of the United States of America
Johannsen L
(2017)
Human bipedal instability in tree canopy environments is reduced by "light touch" fingertip support.
in Scientific reports
Van Casteren A
(2011)
Why don't branches snap? The mechanics of bending failure in three temperate angiosperm trees
in Trees
Saunders E
(2016)
The International Encyclopedia of Primatology
Description | Increasing mechanical and fossil evidence suggests that human (hominin) terrestrial bipedality originally arose from adaptations for orthograde (upright-trunk) locomotion in the forest canopy. In this study, our primary objectives were to quantify the mechanical interactions between arboreal bipedality and flexible branches in orangutans and humans, and to establish whether this behaviour could have been preadaptive for adoption of habitual terrestrial bipedality by early hominins. To achieve this we employed a 3-pronged approach that combined study of the interactions between locomotion and branch compliance during arboreal bipedality by wild orang-utans; development of a portable instrumented compliant-branch system with variable compliance settings to study the mechanics, muscle activity patterns and limb/branch interactions in zoo orang-utans and humans; and finally development of 2-d computer simulation models of walking and running on compliant surfaces to study the stability and efficiency of arboreal bipedality in orangutans, humans and Au. Afarensis. In addition we undertook complementary studies on the postural (rather than locomotor) stability of arboreal bipeds faced with a moving physical and visual environment and the mechanics of orang-utan nest building, as both enhanced our understanding of the interactions between orang-utans and compliant supports. Our primary findings are: 1. Conditions exist in the wild for orang-utans to obtain energy return from flexible branches, much like runners running on springy running tracks 2. Captive orang-utans walking on our instrumented complaint branch were able to obtain up to 60% of the cost of the stride in energy return from the beam 3. Computer models of orangutans identify straight-legged bipedalism as the most effective technique to move on compliant branches 4. Postural stability in the dynamic physical and visual forest environment can be maintained through lightly touching rather than gripping adjacent branches. 5. The mechanical structure of orang-utan nests suggests an enhanced degree of technical knowledge and choice in the construction of nests |
Exploitation Route | We have already used these findings in our consultancy for Twycross and Chester Zoos on how to increase the welfare of captive apes by relating the functionality of captive environments more closely to those experienced in the wild. This impacts both on animal welfare and tourism, since healthy active captive apes generate tourism revenue. These data formed the basis of a NERC Innovation Project to work with Twycross Zoo to redesign their ape enclosures to enhance wildtype behaviours. The equipment built in this grant was also used for another NERC grant led by Lewis Halsey and myself using parkour athletes traversing an arboreal assault course to understand the energetic demands of arboreal locomotion for great apes. The impact of that grant will feed into enhancing performance in parkour athletes and public engagement. |
Sectors | Education,Environment,Leisure Activities, including Sports, Recreation and Tourism,Culture, Heritage, Museums and Collections |
Description | We have disseminated the results from this grant to the general public via an interactive science show - 'Am I An Ape?' This emulates the Royal Society Christmas lectures, but with a lot more audience participation and a touch of Panto! We have delivered this show 18 times to over 2500 children and parents at venues across the UK, including the 2012 Big Bang Science Show at the NEC. Moreover I have delivered public engagement activities for adults in the form of delivering the British Science Festival Presidential Address for Archaeology and Anthropology in 2014 and an invited presentation for the Association of Scientific Educators (ASE) in 2014 regarding ways to teach evolution and biodiversity in schools. We also used modified our design of the compliant branches to help Chester Zoo design tree sway poles for their orangutans to enhance activity levels and physical welfare. We have provided project students to monitor the efficacy of the poles for chester and the results have shown the poles increased activity levels and resulted in the expression of new wildtype behaviours in a captive environment. Chester will now incorporate the design into their new, multimillion pound orangutan enclosure (Islands). As a follow on from the nest building work in this study, we have also set up student projects to explore ways to replicate complex wildtype nest building behaviours in captivity, which are typically very difficult to emulate. The project has identified some mechanisms to encourage complex weaving and bending behaviours (which our NERC study showed were essential to the structural integrity of nests in the wild). We are now writing this up for publication. Most recently we have applied a similar technique at Twycross Zoo, again with a successful outcome. The research undertaken in this grant formed the basis of a successful NERC Innovation grant application to work with Twycross Zoo and the British and Irish Associations of Zoos and Aquariums (BIAZA; the UK zoos representative body) to develop an Enclosure Design Tool that would allow zoos to compare the behaviour of their captive chimpanzees and gorillas to wild conspecifics and will then make recommendations for modifications to their enclosures to enhance wildtype behaviours. The specific impacts are reported in the NERC innovation grant. In the longer term this impact should achieve economic benefits for Twycross and policy benefits for management of captive apes via EU Taxon Advisory Groups (TAG). We are beginning talks with the EU great ape TAG in April 2016. We are hopeful this will be a REF 2020 Impact Case Study |
First Year Of Impact | 2015 |
Sector | Education,Environment,Leisure Activities, including Sports, Recreation and Tourism,Culture, Heritage, Museums and Collections |
Impact Types | Cultural,Societal |
Description | BBSRC IAA |
Amount | £46,169 (GBP) |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 04/2019 |
End | 06/2020 |
Description | Research grant |
Amount | $100,000 (USD) |
Organisation | The ARCUS Foundation |
Sector | Charity/Non Profit |
Country | United States |
Start | 02/2017 |
End | 09/2018 |
Description | Small Grant Fund |
Amount | £64,000 (GBP) |
Funding ID | NE/J005371/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start |
Description | Orangutan Veterinary Advisory Group |
Organisation | Orangutan Veterinary Advisory Group |
Sector | Charity/Non Profit |
PI Contribution | The Orangutan Veterinary Advisory Group (OVAG) support 38 stakeholders in orangutan conservation and health, and represent most of the orangutan sanctuaries in SE Asia. We are working with them in a knowledge exchange partnership. We are providing information on the behavioural ecology of wild orangutans and how the mechanical challenges that wild orangutans face every day can be emulated in captivity to increase the quality of life of captive orangutans and their chances of successful reintroduction, where this is possible. We are delivering this both via the EDT and via advice on general ways to enhance the physical and cognitive challenges posed to captive orangutans by their enclosures. This year will be the 5th year running that we have contributed to their annual veterinary workshop. |
Collaborator Contribution | The OVAG committee formed our Advisory Board for the orangutan sanctuary EDT, which is designed to ensure that the EDT reflects the needs of a wide range of end users, by obtaining input on its design and functionality from representatives of related conservation, sanctuary and policy making organizations. OVAG have built the EDT into their 5 year strategy to be one of their pillars of research activity. We are partners at their annual meetings so we can also develop our knowledge of the core issues for the community and the primary problems in rehabilitating orangutans for life back in the wild. They are also committed to supporting us in refining the EDT for all sanctuaries and to helping roll out the EDT to the sanctuary community once we have completed the refinement process (via a new grant from the ARCUS Foundation) that is funding a 4 year project and international partnership. |
Impact | We have spoken at their annual meetings to showcase the EDT and obtain feedback on its development. We are also currently working with them to quantify their training needs in relationship to accessing research information on the behavioral ecology of wild orangutans and have already delivered 2 sessions on this topic to their staff. |
Start Year | 2017 |
Description | Am I An ape |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | This is an interactive Science show primarily aimed at school children (variations delivered to cover children aged 5-15). It has been delivered many times including the University of Birmingham Christmas Lectures, the Big Bang UK Young Scientist and Engineers fair, and multiple iterations at the Glasgow Science Centre. Other staff have also delivered it to other school-based audiences. It has been delivered to >2500 school children and parents overall. Feedback from the schools has always been excellent, indicating that it has sparked interest in evolution and enhanced understanding of human's place in nature |
Year(s) Of Engagement Activity | 2009,2011,2012,2013,2014,2016,2017 |
Description | Arts Festival |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Public/other audiences |
Results and Impact | I was part of a 'human library' at the Alrewas Arts Festival to answer the questions of 'readers' on human evolution |
Year(s) Of Engagement Activity | 2016 |
Description | BIAZA talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | A presentation to BIAZA's annual research conference entitled 'An Enclosure Design Tool to enable zoos to create integrated, wild-type enclosures for great apes' |
Year(s) Of Engagement Activity | 2016 |
Description | BSF Presidential Address for Archaeology and Anthropology |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | This Presidential address sparked an incredibly detailed debate with the audience that demonstrated a really deep understanding of the issues on their part |
Year(s) Of Engagement Activity | 2014 |
Description | Delivery of Twycross Zoo's Conservation Welfare Talk |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | The title of the talk was 'Aping the apes: translating wild great ape research to zoos'. It was delivered to Twycross Zoo's members and interested general public. The aim was to show the public and particularly the members about our collaboration, and the importance of eliciting wild-type behaviours in the captive management of great apes. Informal feedback was that they really enjoyed learning both about the wild research and the translation of those results into captivity. The audience had not really experienced researchers before, so it exposed them to a different perspective on zoos and their importance in society, and also the impact of academic research. |
Year(s) Of Engagement Activity | 2016 |
URL | http://twycrosszoo.org/conservation-welfare-talk-aping-the-apes/ |
Description | New optimist book |
Form Of Engagement Activity | Engagement focused website, blog or social media channel |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | I contributed a book chapter to a general interest science book entitled 'The New Optimists: Scientists view tomorrow's world and what it means to us'. This book was written to celebrate the 2010 British Festival of Science. There was extensive website an blog material that accompanied it. The primary url is here and mine is detailed below http://newoptimists.com/ |
Year(s) Of Engagement Activity | 2010 |
URL | http://newoptimists.com/2010/07/20/susannah-thorpe-on-orangutans/#more-1024 |
Description | Presentation to Twycross Zoo Staff |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Industry/Business |
Results and Impact | The presentation was: Thorpe SKS, Chappell JM (2015) An Enclosure Design Tool to enable zoos to create integrated, wild-type enclosures for great apes. The aim of the presentation was to inform zoo staff about the aims and objectives of the grant, give them ownership of the process and celebrate the achievements they had made to date. Feedback was excellent and the response of the staff was very positive about the project and its importance to what they do. |
Year(s) Of Engagement Activity | 2015 |
Description | Science Museum Lates |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Thorpe was a winner in a Royal Society competition (only open to Royal Society Fellows) for our lab to take part in the Science Museum Lates' public engagement activity designed to showcase 'the next big thing' in research. Science Museum Lates are adults-only, after-hours theme nights that take place in the museum . |
Year(s) Of Engagement Activity | 2017 |
Description | talk to Association to Science Education (ASE) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Schools |
Results and Impact | This talk was aimed at helping teachers understand and develop material to teach evolution and biodiversity. I explained about the An I an Ape interactive lecture, and provided tips on small practical activities that could be used to convey relevant concepts quickly. |
Year(s) Of Engagement Activity | 2014 |