Wolves use their sense of smell, which is incomparably better developed than ours, to hunt or avoid enemies. However, it is also very useful for communicating with conspecifics. The urine markings they leave along their territory contain messages about their identity, social status, and reproductive state. This type of communication is fundamentally important in the family of dogs. However, it has hardly been studied scientifically until now.
A study co-financed by the SNSF examined how packs living in animal parks react to the scent signal of an intruder. Giada Studer, Klaus Zuberbühler, and Gwendolyn Wirobski from the University of Neuchâtel's Laboratory of Comparative Cognition have shown that leaders with offspring react more strongly to intruders. A better understanding of urine communication could, in the long term, make it possible to develop scent barriers against wolves.
Thirteen wolves, five packs, four animal parks
Between April and June 2024, researchers confronted five packs in four Swiss animal parks with scent markers placed outside their enclosure.
They used scent stations made of an aluminium plate, fixed 30 cm above the ground, to simulate the natural height of a scent marking. On the plates, they simulated the presence of a conspecific not belonging to the pack with three millilitres of wolf urine. To distinguish the reaction to an intruder from the general reaction to something new, the researchers also used human urine.
The thirteen wolves, including six leaders and seven subordinate animals, were continuously monitored with camera traps, and their reactions were analysed.
Leaders react more strongly to new scents
The result is clear: compared to subordinate or young animals, wolves with their own offspring are more often interested in foreign scent markings. "These animals have more to lose," explains Gwendolyn Wirobski, who specializes in animal behaviour and social cognition of dogs and wolves and supervised the study. "They have their territory, their young, and a partner. So it is logical that they pay more attention to these social information," she adds.
The animals approached, sniffed, and left their own urine or feces markings. This can be described as exploratory behaviour. The analysis shows that this behaviour occurred with wolf urine thirteen times more often than with human urine. Overall, the leaders visited the scent stations twice as often as the subordinate pack members, regardless of the urine used.
In contrast, no significant differences in behaviour between the two types of urine can be observed in subordinate animals. Most sniffed the scent stations only briefly.
Complex social communication
A single case illustrates the influence of social status in an impressive way. In a pilot experiment in December 2023, a young, subordinate female showed no reaction to the urine of conspecifics. After the same wolf became a leader in another pack in February 2024, she showed significantly more pronounced reactions - a result confirmed in a follow-up test six months later.
"The animals do not react mechanically to a stimulus. A scent marking is social information. The message it contains is interpreted flexibly depending on one's own status," analyses Gwendolyn Wirobski.
This is an extremely important observation for further action. One of the limitations of the study lies in the type of urine used. "We used wolf urine from the USA, without knowing who it came from. So we only know that the animals reacted, but not what messages we sent," admits Gwendolyn Wirobski. The next step will therefore be to repeat the experiments with previously analysed samples of known animals.
Decoding urine to use it as a barrier
For this purpose, the researchers are now working with a biochemist. They want to record scent profiles by gender, age, and social status of animals and then test the effect of these "scents" on the behaviour of wolves in animal parks and finally in the wild. "Testosterone, estrogen, cortisol: all this and much more likely plays a role in the conveyed message. Our task is to decipher it," says the researcher.
The idea of protecting herds with scent barriers ("biofences") is not new and has already been tested on other animal species such as wild dogs or coyotes. However, it has never been thoroughly investigated. "To know what kind of scent is suitable, in what concentration, at what distance, or how often it should be renewed, we must first understand what is happening on a cognitive level in the wolf when a scent rises to its nose. Only then is it possible to send controlled messages and make them, for example, deterrent," emphasizes Gwendolyn Wirobski. But she believes that it will take years of research before science can provide a reliable toolkit for field application.
Media Contact:
Giada Studer and Gwendolyn Wirobski
Laboratory of Comparative Cognition, University of Neuchâtel
Tel.: Available upon request at +41 31 308 23 87
Email: giada.studer@outlook.com and gwendolyn.wirobski@unine.ch