Even though humans live longer lives compared to their ancestors, we cannot escape the inevitability of aging. However, it may be possible to slow that trend: a new study of ageing in tortoises and turtles has revealed a different pattern of ageing compared to humans and other species.

In a new study published in the journal Science, researchers used data contributed by Kadoorie Farm & Botanic Garden (KFBG) in collaboration with other zoos and aquariums to examine 52 species of turtles and tortoises. The data recorded enabled researchers to discover that, unlike humans and other species, turtles and tortoises defy common evolutionary theories and may reduce the rate of ageing in response to improvements in environmental conditions.

Evolutionary theories of ageing predict that all living organisms weaken and deteriorate with age (a process known as senescence) – and eventually die. Now, using data captured by KFBG and others, researchers from the Species360 Conservation Science Alliance and the University of Southern Denmark show that certain animal species, such as turtles and tortoises, may exhibit slower or even absent senescence when their living conditions improve.

Out of 52 turtle and tortoise species, 75% show extremely slow senescence, while 80% have slower senescence than modern humans.

"We find that some of these species can reduce their rate of ageing in response to the improved living conditions found in zoos and aquariums, compared to the wild," said study co-author, Prof. Dalia Conde, Species360 Director of Science, Head of the Species360 Conservation Science Alliance. “In addition, modern zoological organizations play a significant role in conservation, education and research”

This study also demonstrates the immense importance of conservation centres, zoos and aquariums in keeping records that can help advance scientific discovery. 

KFBG is a member of Species360, a non-profit organization which maintains the Zoological Information Management Systems (ZIMS) – the largest database on wildlife in human care. As part of our commitment to conservation and providing high standards of animal care, we use ZIMS to keep detailed records of our rescued animals and our animal collection and as a holder of turtles and tortoises we actively collect and share data in ZIMS on these species, information that has directly contributed to this study.

Turtles keep growing after sexual maturity

Some evolutionary theories predict that senescence appears after sexual maturity as a trade-off between the energy an individual invests in repairing damages in its cells and tissues and the energy it invests in reproduction, so its genes are passed to the next generations.

This trade-off implies, among other things, that, after reaching sexual maturity, individuals stop growing and start experiencing senescence, a gradual deterioration of bodily functions with age.

Theories predict that such trade-offs are unavoidable, and thus senescence is inevitable. In fact, this prediction has been confirmed for several species, particularly mammals and birds.

However, organisms that keep growing after sexual maturity, such as turtles and tortoises, are believed to have the potential to keep investing in repairing cellular damages and are thus thought to be ideal candidates for reducing and even avoiding the harmful effects of ageing.

"It is worth noting that the fact that some species of turtles and tortoises show negligible senescence does not mean they are immortal; it only means that their risk of death does not increase with age, but it is still larger than zero. In short, all of them will eventually die due to unavoidable causes of mortality such as illness," indicated by another of the researchers behind the study, Dr Fernando Colchero, Principal Statistical Analyst, Species360 Conservation Science Alliance.

Turtles and tortoises may not live forever, but they have the ability to live much longer than almost any other species. KFBG manages an assurance population of Golden Coin Turtles, a species close to extinction in the wild. The centre also supports in-situ conservation efforts to protect the native  Big-headed Turtles. Another important role played by KFBG involves the rehoming of turtles and tortoises seized from the illegal wildlife trade. It seems that as a surprise by-product, in the studies associated with these programmes, we may be contributing to longevity as well!

The article is available here: https://www.science.org/doi/10.1126/science.abl7811

For more information about the study and other projects using ZIMS data, please visit: https://conservation.species360.org/in-the-news/ 

About Species360:

• Species360 is a global non-profit that facilitates international collaboration in collecting, sharing, and analysing knowledge on wildlife.
• Species360 maintains the Zoological Information Management Systems (ZIMS), which is trusted and used by more than 1,200 aquariums, zoos, wildlife centres, sanctuaries, universities, and governmental organizations in 101 countries around the world.
• ZIMS is the world's most comprehensive database of knowledge on more than 22,000 species, increasing vital information about the animal kingdom.
• ZIMS is used to establish best practices in aquatics, husbandry, enrichment, medical care, animal welfare, reproduction, population management, and conservation, and to provide Global Medical Resources to wildlife professionals worldwide.
• The Species360 Conservation Science Alliance is a global alliance of 240 research partners.
• The Conservation Science Alliance harnesses the power of aggregated data in ZIMS and transforms it into scientific information to inform animal welfare and conservation decisions.

For more information: www.species360.org