People love turtles. There just seems to be something about them that innately makes most of us think they are cute or at least pretty cool. Third-year biology student at Mt. A, Gillian Currie, states that her love of turtles stems from her childhood: “I grew up watching shows like Franklin […] I think because they were on the screen growing up, and then also in local zoos or parks, that’s a big part of the reason why I care so much about [turtles].” Early exposure to these amazing and fascinating animals, whether on screen or in person, forms a connection.
Unfortunately, turtle populations are declining worldwide, and losses are largely attributed to human activity, such as habitat destruction of wetlands and waterways, or vehicles hitting turtles on roads. It seems that we tend to hurt the ones we love. These sorts of direct effects have been thoroughly studied, however there may be more to the problem than we are aware of. Clearly becoming roadkill is bad, for the individual and the population, but when different animals live in close proximity, they inevitably alter each other’s behaviour. If you have roommates, think about the ways that you may have changed since moving in with them— over time we change how we act based on those around us. This can sometimes lead to bad habits, and for turtles, changes in their behaviour caused by human activity could be putting them at risk.
Recently, Audrey Turcotte and a group of researchers from the University of Ottawa and Université de Sherbrooke conducted a study to assess the effect of human activity on painted turtle behaviour in the Rideau Canal in Ottawa. To do this, they captured and scored the behaviour of 730 turtles across 22 sites along the canal.
The researchers found that turtles from sites with low human disturbance were more likely to rely on their shell as a defense, pulling in all of their limbs and head. Relying on a defensive strategy they have been honing for millions of years. However, turtles in areas with high human disturbance, like lots of boat traffic, took a different approach. These turtles were more likely to try escaping when captured, and did so by rapidly flailing their legs, hissing, and making threatening biting motions. But this active defense strategy is not playing to the turtles’ strengths, and Turcotte and her team considers this to be much riskier for them. Unlike the Teenage Mutant Ninja Turtles, Painted Turtles are not naturally good fighters.
In other words, human disturbance is bringing these turtles out of their shell and causing them to use more active defense strategies which could put them in a higher-risk situation when facing off with a predator in the wild. This is exactly what was seen during a study of Eastern Box Turtles in 2018. Free Kashon and Bradely Carlson, both researchers at Wabash College in Indiana, discovered that turtles who use risky active defense behaviours tended to have far more injuries from predator attacks compared to those who were more prone to hiding in their shell.
So why the shift in Ottawa painted turtles? Why trade the tried-and-true shell method for a riskier strategy?
Human development is continuously growing, with urban areas becoming more widespread, and along with them, so is human disturbance. “It can be hard for animals to persist in these new urban environments” said Dr. Julia Riley, a leading researcher in the fields of herpetology and behavioural ecology at Mt. A. “But one way they can adapt, and adapt rapidly, is through behavioural change,” Dr. Riley explained.
From this, we have to presume that these Painted Turtles are benefiting from taking a more active defensive strategy. But why and how they are doing so remains a mystery. Yet, with so many populations of turtles declining it is a mystery worth investigating further. In the meantime we all can take action to limit how much our presence in wild areas will impact wild populations. For many of us, a world without turtles is not really a world at all. This innate love of turtles that has been instilled in many of us since we were kids can be a tool for conservation. Apart from not contributing to direct impacts on turtle survival, the next time you see a turtle in the wild, show your love by quietly admiring them from afar!
