Rhino poop attracts all deer (and pigs and more) to the garden, research shows

KATHMANDU — Amid the tall, rustling elephant grass on the banks of a nearly still Rapti River, half a dozen spotted deer approach the mounds of rhino scat. Unbeknownst to them, a nearby camera trap is recording and captures them as they begin to eat, with delicate sniffs and tentative bites, this most unexpected snack.

It’s not just spotted deer (As as); the cast of animals drawn to these unlikely buffets is diverse. Barking deer (Muntiacus muntjac), wild pigs (Sus scrofa), rhesus monkeys (Macaca mulatta) and peacock (Pavo kristatus) were also found wandering among the feces of large rhinoceroses (Rhino unicorn), according to a recently published study that assessed the effectiveness of reintroducing species into habitats from which they had been extirpated.

“We found that while some animals ate bits and pieces of the dung, others ate herbs, seedlings or mushrooms that had grown on the dung,” lead researcher Balram Awasthi of the Chinese Academy of Sciences told Mongabay. “Similarly, there were others that ate insects found on or near the dung, or defecated near the dung or even sniffed at it.”

Rhinos, once abundant in the Ganges and Indus floodplains but now confined to patches of India and Nepal, are known to defecate in the same area repeatedly over a period of time. Researchers have also observed multiple rhinos choosing to defecate in the same spot. This means that the animals that eat or come into contact with rhino poop know exactly where to find it, Awasthi said. “In addition, animals that forage for the poop of multiple rhinos in the same location can find fresh dung almost every day,” he added.

As part of the study, researchers placed cameras near known rhino scat areas in two national parks in the southern plains of Nepal. They placed 22 cameras in Chitwan National Park in central Nepal, a historic home for the rhinos, and eight in Shuklaphanta National Park in the country’s west, where four individuals were reintroduced in 2003. The cameras captured photos and video of every animal that visited the scat sites during the rainy season for more than two years.

The researchers analyzed the images and video footage to determine what types of animals visited, how often they did so, and what they did in the areas, such as eating feces or plants growing there. They also measured the size of the areas and tested the nutrients in the feces.

Despite the relatively small size of the rhino population at Shuklaphanta, where there are only about 17 compared to around 700 at Chitwan, Awasthi and his team observed remarkably similar species using the rhino scat. While 15 species were recorded at the scat sites at Chitwan, there were 13 at Shuklaphanta, with spotted deer considered to be one of the main prey species of Bengal tigers (Panthera tigris), most common in both parks. Analysis of the nutritional content of the feces in both parks showed that animals grazed more around feces with a higher fiber content.

“Based on the study findings, we can say that even with fewer rhinos, the reintroduction of the Shuklaphanta population has likely restored the ecological function of latrines as important resources for other animals,” Awasthi said. He added that reintroducing rhinos to their historical range could restore important ecological processes even if the reintroduction population is small.

Rhino dung is particularly nutritious because of the animal’s inefficient digestive system, said researcher and conservationist Jhama Karki, who was not involved in the study. Rhinos are known to eat up to 50 kilograms (110 pounds) of vegetation each day.

Karki, a former Chitwan National Park manager and grassland management specialist, said much of the plant material rhinos consume passes through their guts only partially digested. This creates a valuable food source for other animals, rich in nutrients and in some cases easier to digest than raw plant matter, he told Mongabay.

Rhinoceros dung also helps to spread the seeds of various plants across the landscape; as these take root and grow, they also become a food source for other species. For example, the spread of the “rhinoceros apple tree” (Trewia nudiflora) is believed to be facilitated by rhinos. The poop is also home to dung beetles and other insects that are then eaten by birds and other small animals. Likewise, the rhino’s thick, hardened skin harbors dozens of species of parasites that birds love.

Shuklaphanta’s findings show that translocating rhinos can be successful, but actually reintroducing the animals to their historic habitat in Nepal is fraught with challenges. Between 1986 and 2003, several attempts to establish new rhino populations failed largely due to a combination of factors, including inadequate planning, political problems, a long-running insurgency, and persistent poaching.

Learning from these challenges, conservation efforts after 2016 have emphasized scientific planning, enhanced habitat security, and community engagement. However, political issues and financial constraints continue to pose obstacles to program expansion.

In addition to the rhinos, conservationists say there is a need to relocate other megaherbivores, such as the gaur ((Bosgaurus) and marsh deer (Rucervus duvaucelii), because they also perform important ecological functions, such as natural management of grasslands, Karki said. This is important because conserving grasslands is also key to saving Bengal tigers, he added.

Banner image: Two one-horned rhinos graze on grass outside Chitwan National Park in Nepal. Photo by Abhaya Raj Joshi

Abhaya Raj Joshi is a staff writer for Nepal at Mongabay. Find him at 𝕏 @arj272.

Nepal takes time to take stock in attempt to create new rhino population

Quote:

Awasthi, B., McConkey, K. R., Aluthwattha, S. T., Chen, C., & Chen, J. (2024). Restoring ecological function: interactions between vertebrates and latrines in a reintroduction of Rhino unicorn. Biological conservation, 294110611.doi:10.1016/j.biocon.2024.110611