A study maps how Gir lions mark scent and territory

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08-07-2025

Mammals, most prominently carnivorous species, use scent-marking as a crucial form of communication. Lions, for example, use urine, faeces, and secretions from scent glands to leave behind long-lasting chemical signals on trees and trails. While these are invisible to the human eye, they carry a meaning for other lions in that area.
A study conducted in Gujarat's Gir Forest focussed on decoding some of this hidden communication. 'This is the first detailed scientific study of scent-marking in free-ranging Asiatic lions, and it reveals how scent is a powerful tool for territory defence, mate attraction, and social interaction,' says Mohan Ram, Divisional Forest Officer, Wildlife Division, Sasan-Gir, Gir National Park and Sanctuary, and one of the lead researchers.
Leaving a mark
Gir Forest, which includes a national park and sanctuary, is spread across nearly 1,900 square kilometres in Gujarat's Saurashtra region. It is home to over 40 species of mammals, including leopards, hyenas, and jackals, but the lion is its undisputed icon.
To understand how the big cats use scent to communicate, researchers collaborated with Gir's seasoned field trackers. These experts helped identify trees that showed signs of regular scratching and are favoured spots for lion scent-marking.
At 36 such locations, the team installed motion-triggered infrared cameras between March 2022 and April 2024. 'Across three seasons, we faced all kinds of challenges, from sensor triggers caused by birds or wind to monsoon rains that washed away scent marks. Reaching camera trap locations during heavy rain was a task in itself. Plus, the volume of data collected was enormous, and it took a lot of effort to sift through and sort out usable footage,' says Ram.
Each time a lion passed by the cameras captured a short video and a photograph. In total, they logged over 15,000 wildlife detections, of which 1,542 featured lions. Every lion video was carefully analysed for specific behaviours such as sniffing, scratching, spraying, rubbing, and even climbing. 'Camera trapping helped us capture behaviour without disturbing the lions. We also kept the camera settings standard across sites and seasons to ensure consistency,' says Ram.
Researchers also documented tree characteristics such as species, height, girth, and proximity to roads or water to understand what made certain trees more likely to be used as scent posts.
The data was then grouped by season, time of day, the lion's age and sex, and the traits of the marked trees. Using statistical tools, the team mapped out behavioural patterns and scent-marking preferences across the Gir landscape.
Marking scent
Among all observed behaviours, sniffing was the most common, accounting for nearly 40% of the recorded actions. This was followed by scratching (30%) and spraying (12%). Young lions were more likely to climb trees, possibly as playful behaviour or a way of learning.
Males were the more active scent-markers, often around pride territories. Females also left their mark, especially when they were in heat. 'It's a key part of territorial and reproductive strategy in a species with such a limited geographic range. Sub-adults were also seen using the same trees repeatedly, almost like they were learning how to mark territory,' says Ram.
Most of these behaviours occurred in the early morning hours, with scratching and spraying peaking at 3.44 am and 4.17 am respectively. This pattern suggests that scent-marking is a deliberate and well-timed part of the lions' daily routines.
Winter turned out to be the busiest season for scent-marking. This aligns with the peak of lion mating season, highlighting the link between chemical communication and reproduction. 'Cooler temperatures meant more lion movement, which led to more marking. Interestingly, lions often chose tilted trees (around 45 degrees) because the spray lands better and holds fragrance longer, especially in the monsoon,' says Ram.
A good marking spot
Lions also didn't mark trees at random. They showed clear preferences for certain species, especially Butea monosperma and Syzygium cumini. 'We noticed that the lions preferred trees with soft bark or gum, species with strong secondary metabolites, likely because the scent tends to linger longer. Teak trees were avoided; the bark is too hard to claw,' says Ram.
Location played a key role too. Most of the marked trees were near forest trails and water sources. Trails serve as lion highways, ideal places to advertise presence to rivals or potential mates. 'The preferred trees were often near trails, indicating lions may be aligning marking behaviour with movement corridors, possibly even taking human presence into account,' explains Ram.
Moist environments may also help preserve chemical signals for longer durations. Scrub habitats, in particular, recorded more scent-marking activity. Their open structure likely makes scent-posts more visible and accessible.
Studying behaviour
Asiatic lions differ from their African counterparts in many ways. They live in smaller groups, don't breed in synchrony, and are confined to a single, limited landscape in western India. These unique conditions shape how they interact, compete, and survive.
By identifying where and when scent-marking takes place, this study offers valuable insights into lion behaviour. The findings can help conservationists refine strategies for habitat protection, water management, boundary marking, and lion monitoring ensuring the continued survival of India's last wild lions. 'Knowing which tree species lions prefer can guide habitat improvement efforts. It can even help prevent poaching by identifying high-use marking spots,' says Ram.
The researchers recommend that future studies combine scent-marking data with GPS collaring to track individual lions over time. This approach could reveal more details such as whether specific lions favour particular trees, and how their marking behaviours shift with seasons, age, or social status.
All these insights could be particularly valuable as the lion population eventually grows and begins expanding into Gir's neighbouring areas. 'It can directly inform habitat planning beyond Gir, and support strategies for lion movement and coexistence with local communities,' Ram says.