When it comes to trauma, humans aren’t the only ones to bear the scars of their past. Just as an abused dog can remain fearful years after adoption, wild animals are deeply scarred by the ordeals they go through. A discovery that shakes up our understanding of the animal world and which could help us implement better strategies for the rehabilitation or protection of species.
The well-kept secrets of Rocky Mountain marmots
In the heart of Colorado, a unique scientific story has been unfolding for more than sixty years. In the open-air laboratory in the Rocky Mountains, researchers methodically followed the adventures of a colony of yellow-bellied marmots (Marmota flaviventris).
These small rodents, cousins of the marmots that populate Europe (Marmota mumbled) can live up to fifteen years and have revealed their secrets through thirty generations of careful observations. Each year, more than 200 individuals were identified, marked and monitored daily during their active period, from April to September.
A gold mine for scientists who sought to understand how difficult experiences shape the fate of these animals. Females, particularly faithful to their native colony unlike males who tend to disperse, have become the focal point of this innovative research.
New light on animal vulnerability
Inspired by studies on childhood trauma in humans, researchers have developed a “ cumulative adversity index » specific to wildlife. A tool to measure all the trials and difficulties that yellow-bellied marmots encounter throughout their lives.
Unsurprisingly, their approach proved rich in learning and revealed a complex reality: these marmots don’t have an easy life. Pressure from predators (wolves, bears, coyotes, birds of prey, foxes and of course, humans), extreme weather conditions, loss of their parent, etc.
On the other hand, their observations revealed a rather surprising component; the very composition of their siblings can influence their destiny : Females born into litters with many males develop masculinized behaviors, probably due to prenatal exposure to testosterone (male sex hormone). This masculinization, although invisible to the naked eye, radically reduces their life expectancy and their ability to reproduce.
This is just one example of other early traumas identified by the study. The overall observation is quite sad. Whether it is a predominantly male sibling, a late spring or the disappearance of the mother, only one of these traumatic experiences before the age of two is enough to halve the chances of survival as an adult.
Towards a new approach to conservation
Why is this discovery so important? Because it could serve as a new basis for establishing more effective conservation methods. Rather than focusing on a single threat, managers of natural spaces could adopt a more holistic vision, taking into account the accumulation of stress suffered by animal populations.
Faced with the challenges posed by global warming, for example, it is possible to imagine concrete solutions for these little marmots. Temporary closure of hiking trails during critical periods or implementation of dietary supplements to compensate for the effects of unfavorable weather conditions.
An index like the one developed by this team could thus serve as a guide and identify the species most at risk to assist them. Similar solutions have already been successfully tested on other species such as primates and hyenas. This approach would allow us to better understand how animals adapt – or not – to the multiple pressures of their environment. A complete change in our way of thinking about conservation, which reminds us that animal suffering, far from being a simple anthropomorphic projection, is a measurable reality with very real consequences.
- Rocky Mountain marmots, tracked for 60 years, show that their traumatic experiences significantly reduce their chances of survival and reproduction.
- A ” cumulative adversity index » was developed to measure the impact of early trauma on these marmots: predators, loss of the mother, weather conditions, etc.
- These discoveries could inspire more global conservation strategies, taking into account the accumulation of sources of stress in animal populations.
