New research reveals that the endangered red-nosed cuxiu monkey targets weak spots in hard fruit husks to feed efficiently and protect its teeth, offering insights into evolution, energy conservation, and urgent conservation needs.
In the heart of the Brazilian Amazon, a rare and endangered monkey has been found to use a surprisingly sophisticated feeding strategy. The red-nosed cuxiu (Chiropotes albinasus) doesn’t just bite into fruit; it targets the weakest points on hard-husked fruits to access seeds with minimal effort and risk of dental damage.
This behaviour, detailed in a new study published in the journal Biotropica, shows that the cuxiu’s feeding technique is not only energy-efficient but also crucial to its survival. With powerful jaws and specialised teeth, the monkey could bite anywhere, but instead, chooses precision over brute force.
‘It’s a bit like nature’s version of keyhole surgery,’ said NRI’s Dr Adrian Barnett, who led the study. ‘These monkeys are using finessed foraging to avoid injury and save energy, both vital in a challenging environment.’
The study analysed the distribution of bite marks on the husks of over 800 fruits from 27 tree species in the Tapajós region of Brazil. In fruits with natural seams (called sutures), the cuxiu overwhelmingly bit along these lines, areas that required the least force to penetrate. This mirrors tactics used by carnivores like big cats, who bite prey at vulnerable spots to avoid breaking their teeth.
But this is not just a story of clever feeding. The red-nosed cuxiu is listed as endangered, with its survival threatened by deforestation, habitat fragmentation, and the loss of the specific tree species it depends on. Its range is restricted to a narrow corridor between the Madeira and Xingu rivers in northern Brazil, making it especially vulnerable to environmental change.
‘Understanding how this species interacts with its habitat is key to protecting it,’ Barnett added. ‘If we lose the trees it feeds on, we risk losing the cuxiu itself. This research helps us understand key elements of the bigger picture: how behaviour, ecology, and conservation are all connected.’
Co-author Dr Tadeu de Oliviera (Federal University of Minas Gerais) added: ‘This study delves into the complexities of the natural history of the vulnerable red-nosed cuxiu. By unravelling these mysteries, the study significantly enhances our understanding of the species' life cycle and dietary habits, knowledge that is essential for developing effective, tailored conservation strategies.’
The findings also open doors for further research into other seed-eating primates and raise questions about whether similar strategies exist in smaller primates or other seed-eating mammals. They also highlight the importance of preserving the complex ecological relationships that sustain biodiversity in the Amazon and other similar landscapes.
Co-author Dr Sarah Boyle (Thompson Rivers University) said: ‘This study highlights how these cuxiu monkeys often selectively bite fruits where the fruit is more likely to open. Such information is important in understanding foraging behaviour in this species and closely related species, many of whom are experiencing anthropogenic pressures that impact the species' conservation outlook.’
As conservationists work to understand and protect the Amazon, studies like this remind us that even the smallest behaviours, such as where a monkey chooses to bite, can carry profound evolutionary and ecological significance.
For more information, contact Dr Adrian Barnett |