A Life in 24 Hours… or 200 Years!
The Astonishing Secrets of Animal Longevity
Why do some animals live for only a few hours while others can make it through two centuries? In the animal kingdom, time certainly does not pass at the same pace for everyone. And while size plays a role in longevity, it is far from being the only piece of the puzzle.
At Zoo de Granby, several animals illustrate this fascinating diversity. Sarah, our elephant, will soon celebrate her 43rd birthday, while Nash, our white-faced saki, is already 36 years old. Simsa, our tigress, has just celebrated her 16th birthday. These ages are not only a testament to the remarkable longevity of certain species, but also to the advances made in the care, nutrition and well-being of animals under human care.
A Day… or Two Centuries?
Let’s start with one of the most spectacular examples: the mayfly.
In several mayfly species, the adult stage lasts only a few hours to a few days. An incredibly short lifespan… but one that doesn’t tell the whole story. Before becoming the winged insect we know, the mayfly spends a significant part of its life as an aquatic nymph, sometimes for months or even years. Once it reaches adulthood, its main priority is essentially to reproduce.
At the other end of the spectrum is Jonathan, a Seychelles giant tortoise living on the island of Saint Helena. Born around 1832, he is now at least 194 years old, making him the oldest known living land animal (a record officially recognized by Guinness World Records). His age is a conservative estimate: when he arrived on Saint Helena in 1882, he was already considered fully mature. He could, in fact, be even older. It is incredible to think that he has lived through the reign of Queen Victoria, two world wars and the conquest of space!
Between these two extremes, the differences are just as astonishing. A house mouse has a much shorter life expectancy than a blue whale, while certain species of sharks, turtles, birds and bats can reach ages that far exceed what their size might lead us to expect.
Bigger Means Older?
At first glance, the answer seems obvious: yes… but only up to a point! Among mammals and birds, larger species generally have a higher maximum lifespan than smaller ones, but this is far from an absolute rule!
A whale and a mouse are an excellent example of this trend. Comparative analyses nevertheless show that body size does not explain everything: several species live much longer, or much less long, than their size would predict.
The naked mole-rat, which weighs only a few dozen grams, can live for more than 30 years, far longer than a much larger tiger.
Why would size be associated with longevity?
Part of the answer lies in the risk of dying before reaching an advanced age. For a large adult animal, being imposing can provide a form of protection. It is generally less vulnerable to certain predators than a smaller animal. Size can therefore help reduce what biologists call extrinsic mortality, the risks of dying from external causes unrelated to aging itself, such as predation, accidents, environmental conditions or food shortages.
And this is where evolution comes into play. Put simply, when a species has a high chance of dying young, there is less evolutionary advantage in investing heavily in mechanisms that keep the body in good condition for several decades. A strategy favouring rapid growth and early reproduction may therefore be selected for.
Conversely, when an animal is relatively well protected from external dangers, it may be advantageous to invest more in maintaining and repairing the body. Natural selection may then favour traits that allow an animal to remain healthy for longer.
At Zoo de Granby, Supporting Animals in Their Later Years
We must also distinguish between living a long time and aging quickly.
Two species can have very different life expectancies while also following different aging trajectories. Some appear to maintain their physical abilities for much of their lives before declining relatively quickly. In others, signs of aging appear more gradually.
At Zoo de Granby, several animals illustrate this reality in a very concrete way. Sarah, our elephant, will celebrate her 43rd birthday at the end of September. Nash, our white-faced saki, is 36 years old, while Simsa, our tigress, has just celebrated her 16th birthday. These three ages obviously do not have the same significance. The age at which an animal is considered old or geriatric varies greatly from one species to another. In every case, however, aging means that animal care and veterinary teams must pay particularly close attention to the individual’s needs.
Aging can bring changes in mobility, diet, behaviour, social interactions and periods of rest. The first adaptation is therefore often… to observe the animal even more closely in its daily activities. Changes in appetite, weight, the way an animal moves, sleeping habits or interactions with its companions can provide valuable information about its condition.
The Environment Can Change Too
An aging animal may need more time to rest, easier access to certain resources or surfaces that promote comfort and mobility. It may also be beneficial to provide more opportunities for retreat or choice in its daily life. Social life may require adjustments as well. In a species that lives in a group, an older animal may no longer have the same physical abilities it once did to keep pace with others or avoid certain interactions. Group management can then be adapted to reduce the risk of injury and stress while preserving, as much as possible, the social relationships that are important to the animal.
Diet is also part of this adaptation. Nutritional needs change with age and health status. Tooth wear, in particular, can affect an animal’s ability to consume certain foods.
The goal, therefore, is not simply to extend life for as long as possible: it is to help an animal age well.
Aging with Choice, Comfort… and Quality of Life
This approach also reflects the evolution of animal welfare science. Caring for older animals is no longer limited to preventing or treating health problems. It also means preserving opportunities for animals to express natural behaviours, make choices, explore their environment and experience positive moments.
From the mayfly to the blue whale, every species has its own biological clock. And for animals aging under our care, our role is to learn to read that clock and adapt their daily lives so that those additional years are not simply more time on the counter, but comfortable years focused on the animal’s well-being.
