Scent marking in Sunda clouded leopards (Neofelis diardi): novel observations close a key gap in understanding felid communication behaviours

1. What they did

Clouded leopards are among the most secretive and least studied cats. Because almost no scent marking had been seen in them, earlier researchers concluded that clouded leopards do not rely on scent to mark or hold territories. The authors thought this unlikely, since scent marking is common across the cat family.

First, they searched the scientific literature for reports of communication behaviours in every felid species. Then, in Gunung Palung National Park in Indonesian Borneo, they set motion-triggered video cameras at 28 places along research trails, four in each of seven forest types, from June 2015 to February 2016. Cameras were placed where wildlife was most likely to pass, such as trail intersections and ridge lines, and recorded a 20-second video each time they were triggered.

They watched every video, recorded each clouded leopard’s sex and whether it was an adult, identified individuals from their unique spot patterns where possible, and noted every communication behaviour. They then tested whether clouded leopards:

• were found more in some forest types than others;
• returned to the same sites, and whether several individuals used the same sites;
• used some communication behaviours more often than others.

2. What they found

The literature review

Basic information on scent marking is missing for 23% of all felid species, and for another 21% it comes only from one study of captive animals.

Where clouded leopards were recorded

• The cameras recorded 65 clouded leopard visits at 13 of the 28 sites, and communication behaviours at 9 sites.
• At least 9 individuals were identified (6 males and 3 females); 13 visits could not be assigned to an individual. Adult females and juveniles travelled together on 3 occasions. No mating pairs were seen.
• Clouded leopards were recorded in all seven forest types. They were found at more cameras, and visited more often, in the three highest forest types (lowland granite, upland granite and montane) than in the lower forest types.

Returning to marking sites

• Sites with communication behaviours were visited far more often (an average of 6.7 visits) than other sites (1.3 visits). Most visits (60 of 65) were at these sites.
• Seven of these sites were used by more than one individual (up to 4). The overlap seemed limited to males; no females were recorded sharing sites.
• A clouded leopard visited a marking site about every 118 days. Individuals that returned to the same site did so on average every 66 days (range 30 to 103 days).

Ten communication behaviours

• Scent marking: scraping (16.7% of visits), urine spraying (3.3%) and scat deposition (3.3%). Scraping was the most common scent mark. Usually one scrape was made; once, an individual made two scrapes side by side.
• Body rubbing: cheek rubbing (20.0%), claw marking (10.0% in the text), rolling (3.3%) and tail wrapping (1.7%), where a clouded leopard wrapped their tail around a tree trunk.
• Vocalizing: calls (3.3%).
• Investigating: sniffing (olfaction, 56.7%) and the flehmen response (13.3%), where the cat lifts their head and curls back the upper lip.
• Clouded leopards investigated marks (58.3% of visits) more often than they made them (38.3%). Sniffing was the most common behaviour of all.

3. What they concluded

• Contrary to earlier descriptions, Sunda clouded leopards do scent mark, using at least 10 communication behaviours. Sniffing, scraping and cheek rubbing were the most common.
• Tail wrapping has not been reported before in any cat and may be unique to clouded leopards. It may relate to their tree-climbing habits, or may be a way of leaving scent. Cameras in the study area have recorded it at least once more since the study period.
• Their behaviours are remarkably similar to those of other solitary cats, especially leopards and snow leopards, so their scent marking probably serves the same purposes: marking territory and finding and choosing mates. As in other cats, males seem to overlap and compete at marking sites, while females rarely overlap.
• The differences between forest types are intriguing, but the data are too few for firm conclusions.
• More research is needed on how scent marking differs by individual, sex and age, over longer periods, because scent marking changes with the seasons.

6. Other technologies, skills or innovations

• Motion-triggered video cameras (Bushnell TrophyCam) recording 20-second videos with a 10-second pause between triggers. Video, rather than still photos, allowed behaviours to be identified and counted.
• Individual identification from unique spot patterns (Figure 5 shows how).
• A systematic literature review comparing communication behaviours across all felid lineages (Figure 1).

7. Implications for conservation (from the paper)

• Only two telemetry studies of clouded leopards existed, so little is known about their numbers and how they use space.
• Repeated visits by identifiable individuals to scent marking sites should help improve population estimates from camera traps.
• Their loyalty to marking sites could also help researchers capture clouded leopards to fit telemetry collars. Such studies are urgently needed to plan conservation for this endangered cat in Borneo.