A female sloth bear named Bindhu, who Wildlife SOS biologists had placed a GPS collar on, became the first documented sloth bear to embark on a long-distance journey, known as a long-distance dispersal. Her unique journey, which was tracked via satellite, was remarkable for many reasons. Most importantly because it gave biologists critical knowledge that can be key for conservation. We interviewed one of the Wildlife SOS biologists, Thomas Sharp, who analyzed her movements so we could better understand the findings of this research.
First, tell us about why you were wanting to track the movements of bears with GPS collars?
Sloth bears are a wide-ranging large carnivore. They set up home ranges in which they live their day to day lives. Understanding the size of a sloth bear home range, and the primary resources found within a home range, is important to conservation efforts. To this end, we put GPS collars on 10 individual sloth bears in southern India. This is the first large scale GPS collar study of sloth bears anywhere within their range.
Tell us a little information about Bindhu?
Wildlife SOS first became aware of Bindhu through the sloth bear camera trap studies in Gudekote Sloth Bear Sanctuary in Karnataka, India. At the time she was a small cub living with her mother and her sister, Sindhu. After roughly 2 years Bindhu and Sindhu became independent of their mother, but continued to live close to their mother. This is normal bear behavior as females predominantly establish their home ranges adjacent to and overlapping with their mothers home range. However, eventually Bindhu embarked on a long distance dispersal journey across a fragmented landscape in search of a new home.
Bindhu’s journey is called ‘long-distance dispersal, how far did she travel from where she was born?
Bindhu traversed 223 km (138 miles) and a straight line distance of 139 km (90 miles) to her new home in the neighboring state of Andhra Pradesh in the Penukonda Reserve Forest near Gangapalli.
How long did it take her to make the journey?
It only took Bindhu 12 days to make this long journey. She generally traveled at night.
Explain why she likely made this journey?
Female long distance dispersal is much rarer than male long distance dispersal, at least as documented in other bear species. If resources are adequate where the bear was born, females tend to stay in the area. However, if resources are scarce, potentially due to several bears already living in the area, then females may go in search of a new home. And according to the “Resident Fitness Hypothesis” the smaller of the siblings will disperse. This holds true in our case as Bindhu was slightly smaller than her sister Sindhu. Interestingly, the winter after Bindhu left, Sindhu, who stayed in the area where the sisters were born, gave birth to 2 cubs or her own.
Long distance dispersal is dangerous because there are a lot of human barriers that they need to successfully make it through, can you give us some examples of ones she navigated?
Long-distance dispersal is a potentially dangerous activity for wildlife species even under the best of conditions. However, dispersing across a fragmented landscape is exceptionally dangerous for any wildlife species. And long-distance dispersal is vital to maintaining gene flow between isolated wildlife populations. Large carnivores and other wide-ranging mammals are slowly being extirpated from parts of their range due to landscape changes and the inability of wildlife to cross barriers successfully. During Bindhu’s journey, she crossed one 4-lane highway, seven 2-laned roads and 2 railroad tracks. Luckily, there are small islands of natural habitat amidst the sea of agricultural lands. She was able to use the natural habitats during parts of her journey.
What were you thinking when you analyzed the results of her travels?
We were very surprised how quickly she made the journey. We were also surprised at how efficiently she made the journey, she never turned around or seemed to get lost while traveling to an area she had never been. It made us wonder if there were scents or mariners she was picking up on during her journey. Had other sloth bears made this journey before her?
How will this study help with protecting sloth bears in the wild?
First of all her journey did highlight the importance of small habitat patches. Even if some patches are too small for a sloth bear to live in, they are still important during long-distance dispersal. We understand now that saving even small habitat patches is important. Secondly, identifying corridors of sloth bear movement means we can protect these corridors.
What do you know about how she is doing where she has now established herself?
Bindhu’s collar fell off roughly 4 months after she settled in her new home range. Wildlife SOS is now in talks with the Forest Departments in Andhra Pradesh who are also interested in protecting sloth bears. They were also very excited to see the results of Bindhu’s movements from eastern Karnataka. We hope to set up camera traps in the future to see if we can locate Bindhu and see how she is doing.
It sounds like your team is quite attached to Bindhu, can you comment on that?
The entire field team is attached to Bindhu. It is hard to know an animal that long, from cub to adult, without getting attached. And we have documented other parts of her life not even mentioned here. To be clear, she is not like a pet, but rather a friend you have known since they were born. We’ve followed her adventures and lived vicariously through them. Of course she is completely unaware of her secret friends and admirers but we are out here, trying our best to ensure a life for her and her future offspring.
Anything else you would like to say about Bindhu or this study?
Bindhu has become, at least to us, one of the most famous wild sloth bears to ever exist. We will be writing about her more in the future. And as for the study, a scientific manuscript on the home ranges and long-distance dispersal of sloth bears is being prepared for publication and will hopefully be out by the end of 2025.
