There are hardly 400 of them left in the world and in a rare visual treat, a Sumatran tiger has been captured on a camera-trap study, giving hope that the critically endangered species (Panthera tigris sumatrae) is still out there.
Scientists deployed motion-sensitive camera traps across a 50-square-mile swath of Bukit Barisan Selatan National Park in southern Sumatra and, over the course of eight years, recorded the haunts and habits of dozens of species, including the Sumatran tiger and other rare and endangered wildlife like clouded leopards.
The cameras captured a total of 39 animal species, including critically endangered Sumatran tigers, Sumatran elephants and Sunda pangolins, as well as carnivores including Asian golden cats, marbled cats, Sunda clouded leopards, Malayan sun bears and masked palm civets.
The Sumatran tiger is in extreme danger of extinction, with fewer than 400 of them left in the world today. This is a stark contrast to its number in the 1970s, when there was an estimated 1,000 Sumatran Tigers in the wild.
"Camera traps are a good way to document a community of terrestrial animals," said Max Allen, a wildlife ecologist at the Illinois Natural History Survey (INHS) who led the research.
The INHS is a division of the Prairie Research Institute at the University of Illinois at Urbana-Champaign.
The frequency and time of sightings revealed that the tigers were most active during the day, with the majority of sightings in midday.
For example, camera sightings of Sumatran clouded leopards - which are not strictly nocturnal - dropped off precipitously in the hours before noon and picked up a bit in late evening, when tigers were rarely seen.
"Sumatran tigers and Sunda clouded leopards compete for larger prey, and tigers are likely to attack them on sight," Allen said in a paper reported in the journal Animal Biodiversity and Conservation.
The behaviour of smaller cats, however, suggests that they do not fear or actively avoid tigers.
"The daytime activity of the marbled cat, for example, actually overlaps highly with that of the tigers," Allen added.
It's likely the marbled cats are small enough to be eating prey - like rodents - that are of no consequence to tigers.
Surveys from previous studies captured eight species that the camera traps missed, however.
These include the critically endangered Sumatran rhinocerous, the endangered dark-handed gibbon and the endangered hairy-nosed otter.
In an earlier camera-trap study of Sunda clouded leopards in Borneo, Allen and his colleagues discovered that the male clouded leopards would scent mark, scratching and urinating to establish their territory and to attract mates - something other researchers had never observed before.
"There are gaps in our knowledge that camera traps can fill. It would be difficult to document these behaviors and interactions by other means," said the researcher.
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