Sumatran Rhinoceros :: Dicerorhinus sumatrensis
Bad at Goodbyes : Episode 005
The Sumatran Rhinoceros is a critically endangered mammal native to Southeast Asia, specifically Indonesia.
- (00:05) Intro
- (02:05) Species Information
- (15:57) Rhino Singing!
- (28:53) Citations
- (30:40) Music
- (39:23) Pledge
Research for today’s show was compiled from
- International Rhino Foundation – https://rhinos.org/blog/the-curse-of-the-unicorn/ and singing Delilah – https://www.youtube.com/watch?v=HQ-lQ4ABlCU
- PBS’s Nature – https://www.pbs.org/wnet/nature/blog/rare-millennia-sumatran-rhinos-brink-extinction/ and https://www.pbs.org/wnet/nature/rhinoceros-introduction/1179/
- World Wildlife Federation – https://www.worldwildlife.org/species/sumatran-rhino
- Animal Diversity Web at the University of Michigan – https://animaldiversity.org/accounts/Dicerorhinus_sumatrensis/
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A note on accuracy: I strive for it! These episodes are well-researched and built from scholarly sources, hoping to provide an informed and accurate portrait of these species. That said, I’m an ambient musician! I am not an academic and have limited scientific background. I may get things wrong! If you are using this podcast for scholarship of any kind, please see the cited sources and double-check all information.
Rough Transcript
Intro 00:05
Welcome to Bad at Goodbyes.
On today’s show we consider the Sumatran Rhinoceros.
Species Information 02:05
The Sumatran Rhinoceros is a critically endangered mammal native to Southeast Asia, specifically Indonesia.
The Sumatran Rhino is of course a rhinoceros, a species that the fossil record suggests originated 55 million years ago. Then believed to have arrived in Asia about 20 million years ago and then the Sumatran Rhino diverged from its immediate ancestor the long extinct ice age era Wooly Rhino in the Miocene period. So, as a unique species the Sumatran Rhino is roughly 9 million years old. For context, modern humans, homosapiens are only 300,000 years old.
An adult Sumatran Rhinoceros typically stands about 5 feet high, with a head to tail length of about 9 feet. Their weight averages roughly fifteen hundred pounds. The body is stocky and robust, characterized by a long head, a short neck, a thick torso, and a rounded rear with a thin short tail covered in bristly hairs that ends in a thick tuft.
They have short, stout, well-muscled legs, each ending in three toes. Each toe is tipped with a broad, hoof-like nail.
They have a long muzzle. Their eyes are small and dark, surrounded by wrinkly skin. Their ears are relatively large and fringed with hair, they can move and turn and perk them up, aiding in detecting sounds. Their nose is broad with nostrils spread far to each side of the face. They have a prehensile upper lip, prehensile means adapted for holding, seizing, grasping, that they use to grab vegetation. They are herbivores, so they pull greenery into their mouths and then their premolars and molars are specialized for grinding vegetation. They have two horns. The frontmost horn is significantly larger, typically 10 to 30 inches in length. The second horn is smaller, rarely exceeding 4 inches. Both horns are made of keratin, the same protein that makes up human nails and hair.
Though we think of rhinos as having a kind of specialized armored skin, theirs is the same as other mammals, just thicker. It’s primarily composed of three layers: the epidermis, dermis, and hypodermis.
The outermost layer, the epidermis, provides a waterproof barrier and creates skin tone. In the Sumatran Rhinoceros, the epidermis is quite thick and covered in a sparse coat of bristly hair. This hair, though not nearly as thick as like the fur coat of other mammals, still provides some insulation and protection from the elements.
The dermis, the thick layer beneath the epidermis, contains tough connective tissue, hair follicles, sweat glands, and blood vessels that help regulate body temperature. This layer gives the skin its strength and flexibility.
The deepest layer, the hypodermis, is made mostly of fat and connective tissue. It acts as an insulator, conserving body heat.
Across all three layers the skin of the Sumatran Rhinoceros is adapted to a substantive thickness, three times what would be expected of a mammal of its size. It is believed that this adaptation is in response to now extinct predators, and to the density of the forest in its native habitat protecting it from puncture on branch or volcanic rocks.
Sumatran Rhinos are native to Southeast Asia, specifically the Indonesian islands of Sumatra and Borneo. Historically, they were found in a wider range, including China, Myanmar, Thailand, and Malaysia.
They are adapted to diverse terrains, ranging from lowland swamps and coastal areas to mountainous rainforests characterized by high biodiversity with ample precipitation and vegetation.
The climate is tropical, characterized by high humidity, abundant rainfall, and warm temperatures in the 80s year round. This region receives over 200 inches of rain on average.
Plant life includes dipterocarp trees, palms, Torchwood trees, Laurels, ferns, and orchids. Fauna includes fire-tufted barbet, tiger, tapir, graceful pitta, elephant, gibbon, Sumatran treepie and many many more.
The Sumatran Rhino shares its rainforest home with a remarkable and expansive biodiversity.
The Sumatran Rhino itself is a primarily solitary animal, living independently except for mothers with their calves, and brief in heterosexual pairs during the mating season. They establish home ranges, with males (called bulls) having territories up to 20 square miles, while females (called cows) occupy smaller ranges of 4 to 6 square miles. These ranges are spaced out for females with little overlap and interaction, but often do overlap for males.
Sumatran Rhinos are most active during dawn and dusk, primarily for feeding. During the day, they retreat to mud baths; scientists have named this behavior wallowing. It plays a vital role in regulating their body temperature and protecting their skin from parasites and insects. If no natural mud holes are available, they create new mudholes or deepen existing puddles with their feet and horns.
Research suggests that Sumatran Rhinos rotate between a few preferred wallows, using each for several weeks before moving on. They typically wallow in the middle of the day for two to four hours, and then venture out again to forage.
Sumatran Rhinos are herbivores with a diverse diet. Their preferred food sources include small trees, shrubs, and herbs. They are considered browsers, meaning they prefer foliage, rather than grazing on grasses like some other herbivores.
They are generalist herbivores and will sample a wide array of plants, but most feeding on leaves and twigs from saplings and small trees.
Using their prehensile upper lip, Sumatran Rhinos will grasp and pull vegetation into their mouths. They have specialized adaptations in their digestive tract to even break down woody branch fibers.
Although they have never been observed mating in the wild, Sumatran Rhinos are considered to be polyandrous, meaning the female will mate with several males during the breeding season. Females will indicate their fertility by vocalizing, scent marking, and raising their tails near males. Males will nudge the females and if she is receptive, they will mate.
Pregnancy lasts 15 to 16 months, one of the longest among mammals. They birthing a single, reddish-haired approx 100 lbs calf. The new calf is entirely reliant on its mother who singularly provides food and protection for the first year and half of life and continues to nurture their offspring until they reach independence at roughly 3 years old.
Females reach sexual maturity around 6 to 7 years old, and males reach sexual maturity around 10 years old. Females give birth only once every 3 to 4 years, seeing their young to independence before mating again.
It is estimated that the Sumatran Rhino can live up to 45 years in the wild.
Though they are generally solitary animals, they demonstrate intricate social behaviors and communication within their species. They use a variety of vocalizations, including whistles, eeps, and whale-calls, so-named by scientists because it sounds a bit like a higher pitched whale song.
Let me drop the music out for a second and share a brief recording of Delilah, a 3 year old sumatran rhino calf at the Sumatran Rhino Sanctuary in Indonesia, she’s singing.
In that recording, Delilah is receiving a bath from her human caretakers, an event they report that she seems to truly relish; it’s hard not to imagine that she sings in her delight?
————
In the dream I bask in unspecified pleasure, it is barely containable, it is big and childlike, in the dream I am a child, and yet in the dream I still know that not all children have the privilege of joy and I so hold a bit of my wishings for you, that you too may have once known, or one day might know an abundant heartbloooming celebration that has no cause, no origin but that I am and I live, we are and we live and we sing it, in our own tongue for ourselves when we need, and for anyone willing to listen. In the dream.
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Scientists believe vocalizations may serve to attract potential mates, warn others of danger and establish territorial boundaries.
They also mark territory by scraping the soil with their feet and leaving excrement. Scent marking through urine and dung also provides other rhino information about that individual’s sex, reproductive status, and individual identity.
They also communicate at a distance by bending saplings that they do not eat into distinct patterns. Scientists believe these are landmarks, to indicate a junction in a trail.
When in proximity, Sumatran Rhino appear to use body language like posture, facial expression, and ear movement to convey intentions and emotions.
This diversity and complexity of communication is significant because they are not aggressive about defending their territory; though often males will have ranges that overlap with other males they have never been observed fighting, they use non-violent behaviors to resolve resource and reproductive disputes.
In their interactions in the wild with other species, Sumatran Rhinos exhibit shyness and predator avoidance, particularly from tigers who occasionally prey on their young. Their keen sense of smell and hearing detect threats and help them evade encounters.
They share their habitat peacefully with other large herbivores like elephants and tapirs, with whom they may indirectly communicate through scent marking and vocalizations to avoid competition for resources.
The Sumatran Rhinoceros play a pivotal role in sustaining their ecosystem through habitat modification, nutrient cycling, and seed dispersal, which supports overall biodiversity and ecosystem resilience.
As they range for food they create and maintain trails, forging corridors through inhospitable terrain. These trails are used by generations of rhino and also by elephant, deer, boar, and wild dog.
Their ability to dig for water leads to the creation of new waterholes, helping other fauna in their habitat by creating additional access to underground water supply.
Their wallowing behavior also contributes to nutrient cycling. When they roll about in the mud, the rhinos extract enriched sections of fertile soil that coats their skin and they carry these essential nutrients to other areas stimulating plant growth there.
Additionally, they act as seed dispersal agents. Which I love considering. We’ve discussed plant reproduction adapted for wind and water and gravity seed dispersals. Now, rhino dispersal. Their substantial daily dietary intake results in a lot of nutrient-rich dung containing a diverse array of seeds facilitating the propagation of plant species over considerable distances.
All of which directly and indirectly supports both flora and fauna in their habitat. I feel like we are learning this again and again each week: Everyone is vital in every ecosystem.
Threats to the Sumatran Rhino include immediate human encroachment on their habitat, the long term effects of human induced climate change, historical overhunting, and current poaching.
Human encroachment includes forest conversion into commodities and plantations, road development, and natural resource collection, like logging and fishing, all of which reduce the rhino available habitat and increase competition for the resources therein.
Human induced climate change is affecting weather patterns in Sumatra, including unfamiliar shifts in the jet stream El Nino, resulting in decreased rainfall, increased wildfires, and increased risk of extreme damaging weather events.
Historical overhunting has led to a dire population bottleneck, resulting in inbreeding which affects the longterm genetic viability of the species.
Poaching is driven by the demand for the supposed medicinal properties of rhino horns and their male reproductive organs. Petty narcissistic idiot human men, think they will become better sexual partners though ingesting rhino parts, and there is lucrative international blackmarket trade in this foolish cruelty.
Fortunately the Sumatran Rhinos habitat falls within three Indonesian Protected Reserves: Bukit Barisan National Park, Gunung Leuser National Park, and Way Kambas National Park the last of which also houses the Sumatran Rhino Sanctuary. The Rhino has been legally protected internationally since the mid-1970s and Rhino Protection Units have been established by Indonesia’s Ministry of Environment and Forestry to actively combat poaching.
Captive breeding and release programs have been explored since the early 1980s with low success, though the Cincinnati zoo welcomed surviving calves in 2000 and 2013.
The Sumatran Rhinoceros was added to the IUCN Red List of Critically endangered species in 2019 and its population is currently in decline.
It is estimated that less than 50 Sumatran Rhinoceros remain in the wild.
Citations 18:40
IUCN – https://www.iucnredlist.org/species/6553/18493355
International Rhino Foundation – https://rhinos.org/blog/the-curse-of-the-unicorn/ and singing Delilah – https://www.youtube.com/watch?v=HQ-lQ4ABlCU
PBS’s Nature – https://www.pbs.org/wnet/nature/blog/rare-millennia-sumatran-rhinos-brink-extinction/ and https://www.pbs.org/wnet/nature/rhinoceros-introduction/1179/
World Wildlife Federation – https://www.worldwildlife.org/species/sumatran-rhino
Animal Diversity Web at the University of Michigan – https://animaldiversity.org/accounts/Dicerorhinus_sumatrensis/
Wikipedia – https://en.wikipedia.org/wiki/Sumatran_rhinoceros
Music 19:58
Pledge 29:01
I honor the lifeforce of the Sumatran Rhinoceros. I will endeavor to hold its name, a seed of awe and remembrance, gently on my lips. I am grateful to have shared time on our small bright planet with this amazing little being. I lament the ways in which I and my species have harmed and diminished this species.
And so, in the name of the Sumatran Rhinoceros I pledge to reduce my consumption. And my carbon footprint. And curb my wastefulness. I pledge to acknowledge and attempt to address the costs of my actions and inactions. And I pledge to resist the harm of any kin or their habitat, by corporations and governments.
I pledge my song to the witness and memory of all life, to a broad celebration of biodiversity, and to the total liberation of all beings.