Presbyopia in old wild bonobos (Pan paniscus)
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Abstract
Presbyopia, or long-sightedness, is one of the signs of senescence in humans. Many people first recognize it when they approach 40-years-old, though presbyopia progresses gradually with age. Not surprisingly, presbyopia has been reported in old, wild chimpanzees (Pan troglodytes) at Bossou (Guinea) and Mahale (Tanzania). Bonobos are one of our closest living relatives (98.7% identical in genome level) and like us have long development periods and long longevity. We therefore expected to find presbyopia in bonobos. Here we report evidence of presbyopia in wild bonobos at Wamba, Democratic Republic of Congo, during grooming interactions. We used an interchangeable-lens camera to make precise measurements of ear dimensions for each individual, which we then used to determine grooming distance. Age estimates for older individuals were taken when the group was first identified in the late 1970s to early 1980s. We found that grooming distance increases with age. All four bonobos that showed symptoms of presbyopia, i.e. long grooming distance, were estimated to be over 40 years old in 2015. We confirmed that when grooming others, the 4 older individuals kept significantly longer distance between their hands and eyes than did younger individuals. This result indicates that bonobos begin to experience presbyopia in their 40s as do human beings.
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2016. Presbyopia in old wild bonobos (Pan paniscus) PeerJ Preprints 4:e1888v1 https://doi.org/10.7287/peerj.preprints.1888v1Author comment
This is an abstract which has been accepted for the "Chimpanzees in Context" symposium.
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Competing Interests
The authors declare that they have no competing interests.
Author Contributions
Heungjin Ryu conceived and designed the experiments, performed the experiments, analyzed the data, wrote the paper, prepared figures and/or tables.
Kirsty E. Graham performed the experiments, contributed reagents/materials/analysis tools, reviewed drafts of the paper, english grammar checking.
Tetsuya Sakamaki contributed reagents/materials/analysis tools, reviewed drafts of the paper, managements for the field site and works.
Takeshi Furuichi contributed reagents/materials/analysis tools, reviewed drafts of the paper, funding and managements for the field site and works.
Animal Ethics
The following information was supplied relating to ethical approvals (i.e., approving body and any reference numbers):
1. Ministry of Scientific and Technological Research of the D.R. Congo, and 2. Research permissions (MIN.ESURS/SG-RST/026/2014
Field Study Permissions
The following information was supplied relating to field study approvals (i.e., approving body and any reference numbers):
1. Ministry of Scientific and Technological Research of the D.R. Congo, and 2. Research permissions (MIN.ESURS/SG-RST/026/2014
Data Deposition
The following information was supplied regarding data availability:
The research in this article did not generate any raw data.
Funding
JSPS Asia-Africa Science Platform Program (2012-2014 to Furuichi) provided funding for the work. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
