PARIS, Feb 1 — Remember that scene from The Jungle Book movie where Baloo, the friendly, easygoing bear, rubs up against a palm tree while singing The Bare Necessities? Well, it turns out that there’s a scientific explanation for this surprising bear behaviour.
Agnieszka Sergiel, an assistant professor at the Institute of Nature Conservation at the Polish Academy of Sciences, and fellow researchers investigated why some bears vigorously rub their necks, chests or backs against trees. Biologists have long known that bears often rub up against trees to leave their scent on them.
This allows the animals to signal their presence to the males of their species — and thus mark their territory — but also to attract females.
But Agnieszka Sergiel and colleagues put forward a different theory in a study recently published in the Journal of Zoology. Brown bears could, apparently, adopt this behaviour to protect themselves from ticks. Indeed, many trees produce sap or resin with antifungal and antiparasitic properties.
The animals that rub themselves against these trees could therefore use these substances as a protective ointment to keep certain hematophagous parasites at bay.
The researchers tested this theory by catching about 50 Dermacentor reticulatus ticks in meadows outside of Wrocław, in western Poland.
They then placed them one by one in the centre of a clear silicone tube, one end of which was covered by a water-soaked cloth and the other by filter paper onto which turpentine and beech tar had been poured.
The scientists then observed the behaviour of the ticks for several minutes in order to see which end of the tube they would go to.
They found that the insects were trying to avoid the end of the tube with the filter paper, and thus with the turpentine and beech tar — substances that are known “to attract bears and elicit rubbing behaviour,” the research team explains in their paper.
As such, bears appear to rub themselves against trees in order to self-medicate: the resins produced by these plants seemingly protecting them against certain parasites.
As exhausting as it may be, this activity also allows them to deposit their smell in their environment — a win-win situation. — ETX Studio
