Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 February 2020 | 12(3): 15279–15288
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5390.12.3.15279-15288
#5390| Received 06 September 2019 | Final
received 02 December 2019 | Finally accepted 04 February 2020
Ramifications of reproductive
diseases on the recovery of the Sumatran Rhinoceros Dicerorhinus
sumatrensis (Mammalia: Perissodactyla:
Rhinocerotidae)
Nan E. Schaffer 1,
Muhammad Agil 2 & Zainal Z. Zainuddin 3
1 SOS Rhino; IUCN/SSC Asian Rhino
Specialist Group, 2414 Tracy Place, NW, Washington, D.C., USA.
2 Department of Clinic,
Reproduction and Pathology, Faculty of Veterinary Medicine, Bogor Agricultural
University; IUCN/SSC Asian Rhino Specialist Group , Jl. Agatis,
Kampas IPB Dramaga, Bogor
16680, Indonesia.
3 Borneo Rhino Alliance; IUCN/SSC
Asian Rhino Specialist Group, c/o Fakulti Sains Dan Sumbur Alam, Jalan UMS,
88400 Kota Kinabalu,
Malaysia.
1 nan@sosrhino.org (corresponding
author), 2 rhinogil@gmail.com, 3 zainalz.bora@gmail.com
Abstract: The Sumatran Rhinoceros Dicerorhinus
sumatrensis is on the edge of extinction. The decline of this species was initially
attributed to poaching and habitat loss, but evidence presented here indicates
that reproductive failure has also been a significant cause of loss, and
continues to affect wild populations.
Indonesia’s remaining populations of Sumatran Rhino are small and
scattered, with limited access to breeding opportunities with unrelated
mates. This leaves them subject to
inbreeding and isolation-induced infertility, linked to fertility problems analyzed here.
Sumatran Rhino females in captivity showed high rates (>70%) of
reproductive pathology and/or problems with conception, which has significantly
hindered the breeding program.
Technological advances enabling examination immediately after capture
revealed similarly high rates and types of reproductive problems in individuals
from wild populations. The last seven
Sumatran Rhino females captured were from areas with small declining
populations, and six had reproductive problems.
Going forward, capturing similarly compromised animals will take up
valuable space and resources needed for fertile animals. The high risk of infertility and difficulty
of treating underlying conditions, coupled with the decreasing number of
remaining animals, means that the success of efforts to build a viable captive
population will depend upon utilizing fertile animals and applying assisted
reproductive techniques. Decades of
exhaustive in situ surveys have not provided information relevant to population
management or to ascertaining the fertility status of individual animals. Thus the first priority should be the capture
of individuals as new founders from areas with the highest likelihood of
containing fertile rhinos, indicated by recent camera trap photos of mothers
with offspring. In Sumatra these areas
include Way Kambas and parts of the Leuser ecosystem.
Keywords: Extinction, isolation-induced
infertility, pathology, reproduction.
Bahasa
Indonesia Abstrak: Badak
Sumatera Dicerorhinus sumatrensis
berada di ujung kepunahan. Penurunan spesies ini pada awalnya
dikaitkan dengan perburuan liar dan hilangnya habitat, tetapi bukti yang disajikan di sini menunjukkan bahwa kegagalan reproduksi juga telah menjadi penyebab utama hilangnya, dan terus mempengaruhi
penurunan populasi
liar. Populasi
badak Sumatera yang tersisa
di Indonesia adalah kecil dan tersebar, dengan
akses terbatas ke peluang berkembang
biak dengan pasangan yang tidak berkerabat. Kondidi tersebut mengakibatkan terjadinya
inbreeding dan mengakibatkan
infertilitas-akibat terisolasi,
berhubungan dengan masalah kesuburan yang dianalisis dalam tulisan ini. Betina
badak Sumatera di penangkaran
menunjukkan tingkat patologi reproduksi dan / atau masalah
dengan konsepsi yang tinggi (> 70%) yang secara signifikan menghambat program pengembangbiakannya.
Kemajuan teknologi memungkinkan pemeriksaan segera setelah penangkapan dan menunjukkan tingkat dan jenis masalah
reproduksi yang sama tingginya pada individu dari populasi
liar. Tujuh Badak Sumatera betina yang terakhir ditangkap berasal dari daerah
dengan populasi kecil yang menurun, dan ditemukan enam
badak memiliki masalah reproduksi. Badak-badak yang tidak reproduktif selanjutnya akan mengambil ruang berharga dan sumber
daya yang dibutuhkan untuk hewan subur. Risiko tinggi infertilitas dan kesulitan mengobati
penyebabnya, ditambah dengan terus menurunnya
jumlah badak yang tersisa di alam, maka keberhasilan upaya untuk membangun
populasi badak dipenangkaran yang layak akan sangat tergantung
pada pemanfaatan hewan subur dan
penerapan teknik reproduksi berbantuan. Survei in situ yang
lengkap dalam beberapa dasawarsa belum memberikan informasi yang relevan dengan manajemen populasi atau untuk
memastikan status kesuburan
masing-masing hewan. Dengan demikian Prioritas pertama dalam penyelamatan
badak di alam adalah penangkapan individu sebagai sumber darah baru
dari daerah dengan kemungkinan tertinggi mengandung badak subur, ditunjukkan
oleh foto dari dari badak
betina dengan anak-anaknya dari perangkap kamera yang baru-baru ini ditemukan. Daerah tersebut termasuk Way Kambas dan bagian ekosistem
Leuser untuk saat ini di wilayah
Sumatera.
Editor: Anonymity
requested. Date of publication:
26 February 2020 (online & print)
Citation: Schaffer, N.E., M. Agil & Z.Z. Zainuddin (2020). Ramifications of reproductive
diseases on the recovery of the Sumatran Rhinoceros Dicerorhinus
sumatrensis (Mammalia: Perissodactyla:
Rhinocerotidae). Journal of Threatened Taxa 12(3): 15279–15288. https://doi.org/10.11609/jott.5390.12.3.15279-15288
Copyright: © Schaffer et al. 2020. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: SOS Rhino.
Competing interests: The authors
declare no competing interests.
Author details: Nan Schaffer’s (M.S., D.V.M.), seminal work on reproduction of
rhinoceroses, since her residency at the Bronx Zoo in 1981, resulted in the
first extraction of semen with electroejaculation and the first ultrasound of
the female reproductive tract. She was the first to identify the high
prevalence of reproductive pathology in female Sumatran Rhino, which she has
reported on since 1991. Muhammad Agil
(M.Sc. Agr., D.V.M., Dipl. A.C.C.M.) is a senior
lecturer and researcher at the Faculty of Veterinary Medicine, IPB University.
He has studied the reproductive biology and conservation needs of the Sumatran
Rhino since 1993. His work and research interests also include the Javan Rhino,
Banteng and Sumatran Elephant. Zainal Zainuddin (D.V.M.) is a wildlife veterinarian who
was involved with Sumatran Rhino capture, captive management, and assisted
reproductive technologies in Malaysia and Indonesia. Since his work began in
1985, he has handled the veterinary care and pathological analysis of over 20
individual rhinos. He has over 20 publications on this species.
Author contribution: This paper represents decades of
collaborative field work and research among these three colleagues in their
shared mission to recover the Sumatran Rhino genus. N. Schaffer compiled the
data and wrote the manuscript. All authors reviewed and approved the final
manuscript.
Acknowledgements: Authors would like to acknowledge
the multitude of keepers, caretakers and animal managers that made this work
possible.
Introduction
The global population of Sumatran Rhinoceros Dicerorhinus sumatrensis
was estimated at less than 100 individuals at the Sumatran Rhino Crisis Summit
of 2013. For decades, the persistent
decline has been attributed to uncontrolled poaching and habitat loss. Evidence presented here, however, indicates
that reproductive failure (previously only associated with captivity) is an
important factor in the continued decline of this species. The prevalence of reproductive problems across
time and landscapes indicate a need to understand the scope and nature of this
failure for successful recovery.
Between 1984 and 1995, a total of 41 Sumatran
Rhinos were captured in Indonesia (Sumatra) and Malaysia (Peninsular and Sabah)
(Rookmaaker 1998).
The majority of males and females were placed in breeding facilities in
each range country; three were moved to the United Kingdom and seven to the
United States. At that time, the
husbandry of this species was poorly understood and insufficient knowledge
about diet, habitat, social structure, mating behavior, and reproduction
hampered breeding efforts. Introductions
of males and females often led to violent responses. These husbandry gaps resulted in significant
losses in the initial captive population.
Improvements in diet and behavioral management addressed some of these
challenges, yet despite breeding, females were not producing offspring. With the advent of ultrasound in the 1990s,
factors inhibiting conception were revealed (Schaffer et al. 1994) (Image
1). The high rate of pathologic
abnormalities observed in the reproductive tracts of female rhinos from both
Indonesia and Malaysia was initially presented at the 1999 Asian Rhino
Specialist Group Meeting, and published shortly thereafter (Schaffer et al.
2002). In addition, pregnancy failure
was linked to early embryonic death (Roth et al. 2001).
In early 2001, examination of a poached
female in Sabah, Malaysia signaled that the problem was not exclusive to
captivity (Image 2). In 2011 and 2014,
two more females examined immediately after capture from the same geographic
area in Sabah presented with extreme pathologic conditions (Fiuza
et al. 2015; Schaffer 2018). The
Sumatran Rhino was declared extinct in the rainforests in Malaysia in 2015. This trend will have serious implications for
the success of Indonesia’s 2018 Emergency Action Plan to build a productive
captive population with the last Sumatran Rhinos, as set forth below.
Results
This paper is based on records of female
Sumatran Rhinos captured or poached from various sites in Indonesia and
Malaysia between 1984 and 2018.
Available records for husbandry reports, laboratory results, histology,
ultrasound images, and reproductive tract examination were compiled by Schaffer
(2018). Source data and additional
details on individual animals are available on the Rhino Resource Center
website. A summary of the data is
provided in Table 1, which includes animal identification, approximate age,
dates and location of capture, breeding facility location, date of death,
whether the animal copulated, examination results, and name of examiner. Age of adults, parous status, and relatedness
were unknown with the exception of one genetically related breeding pair
(Morales et al. 1997). Despite wide
variability in parameters, the type of reproductive diseases were similar among
individuals, and the rate of disease occurrence was high in all geographic
areas of origin and all geographic areas of captivity, including breeding
sanctuaries in Indonesia (Sumatra and Kalimantan), Malaysia (Peninsular and
Sabah), and all zoos and reserves in the United States and United Kingdom.
Reproductive analysis of captured animals
prior to 2000 was sporadic. Hampered by
a lack of equipment and limited expertise, only three animals were examined
after death at capture. Thus, potential
disease processes and conditions affecting reproduction such as early embryo
death remained unidentified and unrecorded until monitoring was implemented on
a consistent basis. By 2000, a broader
base of available expertise, protocols and reporting standards ensured that the
last seven females captured: a poached female, Ratu,
Rosa, Puntung, Iman, Najaq,
and Pahu were examined and reproductively monitored
from the beginning of their captive status.
Since 1984, of the 32 females brought into captivity, analyses of the
reproductive tract were available for 25 because three animals had not reached
maturity and four had no records. Out of
25, 22 individuals (88%) presented with some kind of reproductive disease. Out of the 22 animals, 14 females did not
conceive despite copulating a few to several times and eight females were
without access to a breeding male.
Females copulated even if they had pathology.
Cysts and Tumors
Uterine cysts and tumors were the most
frequently documented reproductive problems (42%), and were primarily noted on
ultrasound evaluation. Gross
visualization of intraluminal cysts was noted in a female that died in
captivity in 2000 (Lun Parai). A female poached in 2001 had numerous tumors
and cysts. Histology reports regarding
the endometrium were available for only two females: endometrial edema (Dalu) and cystic endometrial hyperplasia (Barakas).
Histopathology on the uterine masses of six
animals confirmed leiomyoma. The
ultrasound images of these tumors were consistent with signs of smooth muscle
fibroma (dense, round circumscribed) and firm on palpation. Tumors occurred in three obviously older
animals (Rapunzel, Jeram, Subur),
five adults (Lun Parai,
Meranti, Mas Merah, Iman, and a poached female), and one young female
(Rosa). The tumors present in Mas Merah
had not changed when examined 10 years after the original exam. Two animals Panjang and Seputih
both presented with only a few cysts when initially examined. Follow-up exams 10 years later revealed that
each had developed tumors in the both the vagina and uterus. Abnormalities were also observed in younger
animals. Minah,
who was born in captivity, had cysts by 14 years of age, but this may have been
due to her exposure to exogenous hormones.
Another juvenile, Rosa, began cycling in 2010 and began to develop
pathology in 2015 (Ferawati et al. 2018).
Early Embryo Death
When ultrasound was finally applied
consistently enough to monitor for signs of pregnancy, animals were found to be
losing embryos. Three monitored animals
(Emi, Ratu and Rosa) entered captivity young, but
subsequently had difficulty maintaining pregnancy. First time pregnancies might account for
first time abortions, but it was unclear why multiple spontaneous abortions
(Emi 5; Ratu 2) occurred thereafter. Rosa was reluctant to breed when she began to
cycle and a few years later she developed significant pathology and is
currently losing embryos.
Unusual Findings
Two females in residential zoos, Dalu (Taman Safari, Bogor, Indonesia) and Dusun (Melaka,
Malaysia and Ragunan, Jakarta, Indonesia) had unusual
histories and pathological findings. Dalu’s reproductive tract had multiple corpus luteum and a
significantly enlarged uterus that revealed edema with hemosiderin without
evidence of infection. After breeding,
Dusun lactated for nine years before her death.
Findings on necropsy noted chronic cystic kidney disease and darkening
of multiple organs, including the skin, suggesting hemosiderosis.
Infection
No signs of infections were identified in the
few histological reports provided. One
female (Panjang) displayed possible infectious processes such as fluid in the
lumen of the uterus. Iman demonstrated a
large tumor and pyometra that cultured as alpha and beta hemolytic
streptococcus at the time of capture.
She subsequently died when the large tumor finally interfered with her
urinary tract.
Discussion
Infections of the uterus were rarely observed
in the Sumatran Rhino, which is consistent with findings reported in other
species of rhinoceros by Hermes & Hildebrandt (2011). Nutritional factors apparently influenced the
development of abnormal conditions in two animals. The predominant signs of reproductive failure
identified in this species are uterine cysts, uterine tumors, uterine
hyperplasia, and early embryonic loss, all of which are indicative of hormonal
imbalances. Hormonal imbalances can be
associated with the factors of age, lack of parity, and the aberrant genetics
inherent in non-producing (isolated) and inbred animals.
Nutrition
Although multiple corpora lutea can be a
normal occurrence in horses and camelids, the greatly enlarged uterine
endometrium in one rhinoceros and prolonged lactation in another indicated
disease. The unusual conditions in both
Dusun and Dalu occurred in the presence of hemosiderosis. Both of these animals were in residential zoo
settings where proper foods were not readily available, and they died before
nutritional requirements for this species were elucidated.
Effects on the reproductive system could have
stemmed from direct deposits of iron into the reproductive organs of rhinos, a
process that can evidentially turn the endometrium dark brown (Nan Schaffer,
pers. obs. 1992), or indirectly from iron deposition into organs such as the
kidney that influence hormone levels.
Kidney failure was the most commonly reported cause of death in the
Sumatran Rhinoceros after gastrointestinal disease (Foose
1999).
An uncommon symptom of chronic kidney disease
is galactorrhea whereby chronic nephritis results in a lack of clearance of the
hormone prolactin (Hou et al. 1985). Dusun was the only animal to present with
this syndrome, and she was also the only one that demonstrated signs of late
pregnancy loss. The histology report on Barakas (San Diego Zoo) showed the multiple system-wide
occurrence of hemosiderosis, which was also evident in this animal’s cystic,
hyperplastic endometrium.
The last two animals to die of hemosiderosis
were a breeding female (Emi) and her offspring (Suci)
at the Cincinnati Zoo. The fact that
their diets had been improved considerably over time may have relieved effects
on the reproductive system. Deaths from
iron overload have become rare as a result of the improved diet available in
semi-wild sanctuaries located in Indonesia and no animals have succumbed to
hemosiderosis since Suci’s death in 2014.
Age
Cysts are most closely associated with age in
horses, and are found in 22% of adult mares and 55% of older mares (Wolfsdorf 2002).
Even though cysts seem to develop as rhinos aged, some apparently younger
animals (Minah, Emi and Rosa) also developed cysts.
Tumors are associated with non-productive
females (Hermes et al. 2004) and have been documented in rhinos as young as 15
years of age (Montali & Citino
1993). The fact that Rosa, a young
non-productive Sumatran female, developed pathology five years after maturity
is an ominous sign for animals in the wild that are unable to stay consistently
pregnant. The progressive nature of the
disease was also evident in Rosa, who initially had few cysts and then
developed a tumor. This was observed in
two additional non-productive animals, who progressed from having cysts to
several tumors. The fact that there are
fewer and fewer signs of offspring in many of the small, scattered remaining
populations of the Sumatran Rhino may be an indication of development of this
disease, which results in the loss of fertility.
Protection of Parity
In other species, parity may provide some
protection from developing reproductive pathology (Parazzini
et al. 1988; Hermes et al. 2004). The
parous state of the Sumatran Rhino has been difficult to assess because the
majority of animals were adult when captured and hymens were rarely checked
when individuals entered captivity. Most
reports of the condition of the hymen are connected with attempts to break the
hymen of the female after the male had difficulty copulating with her. Parity was confirmed in only three animals.
Rima gave birth just after entering
captivity, yet despite regular breeding thereafter, she did not become
pregnant. The fact that she did not
develop cysts until her later years, suggests that her pregnancy protected her
from pathology.
High rates of pathology in females may occur
because they were non-productive before they entered captivity and remained so
afterwards.
Reduced Parity with Early Senescence
An analysis of reproductive events in the
captive population of Sumatran Rhinoceros suggests that premature senescence
occurs in non-productive females.
Ordinarily in mammals, except for humans, reproductive life typically
lasts up until the end of life. Three
older animals had a long period wherein the ovaries were inactive before death:
Jeram was post-productive for 10 years, Rapunzel for
10 years, and Gologob for four years. Bina has never conceived despite multiple
attempts with one male and is presently reluctant to breed with new males,
which may indicate beginning senescence.
Premature senescence with high rates of reproductive pathology, termed
“asymmetric reproductive ageing” in captive White and Indian Rhinoceroses,
reduces the production of offspring in females that experience a prolonged lack
of pregnancy (Hermes et al. 2004).
Notably, pregnancy is common in herds of older White Rhinoceroses in the
wild, suggesting that this may not be a problem in these herds (Kretzschmar, pers. comm. 2018). In the Sumatran Rhinoceros, among the last
seven captured females five presented (soon after capture) with either
pathology or as older animals with quiescent reproductive tracts suggesting
they had reduced breeding opportunities in the wild.
Inbreeding Effects
Small populations often suffer the effects of
inbreeding depression. Deleterious
alleles may have been expressed in Sumatran Rhinoceros males and females which
can predispose females to disease processes such as fibrous tumors (Medikare et al. 2011).
The heritable component of hemosiderosis may have been demonstrated when
Suci, an offspring from a pair of closely related
parents, died from genetically related iron sensitivity (Morales et al. 1997). While Suci’s
brothers survived and became productive, she and her mother succumbed to
hemosiderosis. Moreover, recessive
alleles have been directly expressed as problematic reproductive morphologies,
including an abnormal male penile skin attachments and intact “imperforate”
hymens in two captive females that had their hymens manually broken before
copulation could succeed (Filkins 1965; Tibary 2016).
Attempting to breed animals from highly
inbred populations will severely compromise production. The effective number of
breeders is now so low that recovery of genetic vigor will require careful
genetic mixing. Therefore, infusion of
genetic resources from animals in Kalimantan and the exchange of genetic resources
between rhinos from the northern and southern areas of Sumatra will be vital
for this species survival.
Treatment
Only after females could be closely monitored
within a captive setting could early pregnancy loss be diagnosed and treated
with drugs that prevent embryo loss in other rhinoceros species (Berkeley et
al. 1997; Roth et al. 2004). To date,
all females that have delivered offspring in captivity have been medicated with
progesterone supplements, as demonstrated by Schaffer et al. (1995).
Treatments become increasingly less
successful the more pathology a female develops. Certain types of cysts are more problematic,
but this cannot be confirmed without a biopsy.
Though only one cystic endometrial hyperplasia has been reported, this
condition may have been more common.
Uterine biopsy could be a useful tool in elucidating the reproductive
condition of individuals. Difficulties
sampling the uterine tissue of larger species of rhinoceros have been overcome
and access to the uterus of the Sumatran Rhino has been accomplished (Radcliffe
et al. 2000; Hermes et al. 2009).
Extensive numbers of cysts and/or tumors will
interfere with maintenance of pregnancy.
In domestic horses, treatment of cysts involves mechanical intervention
such as aspiration or hormonal removal.
Procedural complications and reoccurrence of the cysts is common. To date, treatment of cysts in Sumatran
Rhinos with extensive pathology has been unsuccessful and resulted in the
return of cysts (Fiuza et al. 2015). Emi developed a few cysts between successful
pregnancies, indicating it may be possible for females to achieve pregnancy
when cysts are minimal. Although mares
have achieved pregnancy with mild cases of only a few cysts, Panjang and Seputih were breeding with negligible cysts, but neither
produced offspring. Unfortunately, like most animals captured during the 1980’s
and 1990’s, it was impossible to determine whether or not uterine cysts
interfered with embryos in these individuals. The monitoring of Rosa has
revealed that she has developed cysts and a tumor. Embryos are also forming
with breeding, but she is not maintaining her pregnancies despite progesterone
treatments. Unlike Ratu and Emi whose healthy,
pathology-free uteri responded successfully to progesterone treatments, Rosa is
unlikely to become pregnant even with progesterone. Thus, Rosa’s only chance to
contribute to the recovery of this species is through the application of
Advanced Reproductive Techniques.
Leiomyomas were the most common type of
reproductive tumors in the rhinoceros (Montali & Citino 1993). Hermes
& Hildebrandt (2011) described species differences among rhinos in the
typical location of tumors, in the reproductive tract. Indian Rhinos typically develop vaginal
tumors, White Rhinos typically develop uterine tumors, and Sumatran Rhinos
develop both. Early cases of uterine
tumor removal were not successful in the Sumatran and Indian Rhinoceros (Klein
et al. 1997; Foose 1999). Although a few vaginal tumors have been
removed, there has not been a further attempt to remove uterine tumors thus far
(Radcliffe 2003). Some hormone
treatments show promise in shrinking these tumors (Hermes et al. 2016). Other treatment regimens useful for domestic
animals have been explored for non-productive female Sumatran Rhinoceroses
(Radcliffe 2003). Unfortunately, these
animals died before treatment effects could be ascertained. Animals with pathology will be difficult and
time consuming to recover.
Ramifications for Female Sumatran Rhinos
Reproductive problems prevalent in small,
isolated, inbred populations of Sumatran Rhinos in captivity are also evident
in animals in the wild. The first
indication that pathology could be a problem in populations in the wild was
observed in 1986 with the capture of the first animal in Indonesia. The discovery of tumors at the necropsy of
this female within four months of entering captivity suggested that she
developed the tumors before she was captured (Furley
1993). Early capture efforts focused on
capturing “doomed” animals (Nardelli 2014), many of which had or later
developed reproductive problems. The
prevalence of reproductive problems in females, however, became evident in the
wild after 2000 when animals were routinely examined immediately after
capture. Since 2001, newly captured
females have also been from “doomed” areas.
Fertility problems have been pervasive in these “rescued” females. All seven of these female Sumatran Rhinos
captured had reproductive problems: five had reproductive abnormalities that
were observed immediately after capture, and early embryonic death was
subsequently observed in two animals. A
high rate of infertility is inherent in small inbred populations with isolated
females, and it continues to interfere with the growth of captive and wild
populations.
The existence of pathology in females
suggests they have had few, if any, offspring in the wild, and indeed there is
no evidence of births in the areas where rhinos have recently been captured in
Sumatra (Bukit Barisan Selatan and Way Kambas National Parks) and Sabah (Tabin
Wildlife Reserve and Danum Valley). These areas have seen precipitous drops in
rhino populations. For example Way Kambas had 26–31 rhinos according to the 2015 population
viability analysis (Miller et al. 2015), while recent observations indicate the
population now numbers 4–9 rhinos (Marcellus Adi pers. comm. 2019). Areas with steadily declining populations and
little evidence of offspring will continue to provide predominately
reproductively compromised animals.
Credible demographic information about
populations is nonexistent, except for the fact that they are
disappearing. To date, no population
assessment tool or combination of tools including surveys, camera-traps, and
fecal DNA analyses has provided the critical fertility information required to
manage this species in the wild.
Camera-trap photographs of a few females with young can only provide
information on where potentially fertile rhinos can be found; it does not
define or confirm the ongoing viability of the current population or survival
of the species. Realistic information
applicable to the Sumatran Rhino should have been used for successful modeling
of extinction outcomes for this species (Miller et al. 2015). For years we have had all the information we
needed to show that the Sumatran Rhino in Indonesia can no longer be sustained
in the wild, particularly in the face of mounting infertility and negative
growth rates, even with the absence of poaching.
Fertile females are the determinant factor in
the recovery of this Critically Endangered species (Kretzschmar
et al. 2016). When numbers are
critically low and the risk of infertility so high, the fertility status of
every female rhinoceros must be ascertained and constantly monitored, which is
not possible when the status of animals is unknown. Intensive management zones (IMZs) and/or
intensive protection zones (IPZs) are not suitable for this cryptic rainforest
species, because the information necessary for successful management cannot be
obtained within such areas (Ahmad et al. 2013; Payne & Yoganand
2018). Although these management
strategies may apply to the larger African and Asian rhinoceros populations,
which can be observed, monitored and sampled at the individual level, these
strategies are inappropriate and dangerously non-productive for the Sumatran
Rhino (Image 3). The only way to
determine the fertility status of an individual Sumatran Rhino is through
direct, hands-on examination in a captive setting.
After 25 years of perfecting tools and
techniques in captivity, the Sumatran Rhino Sanctuary (SRS) design in Way Kambas is currenly the only
option for successful reproductive management of Sumatran Rhinos. Only in this environment can the essential
management information be obtained, and reproduction optimized. Fertility monitoring for this species
requires confirming reproductive events by comparing ultrasound images with
individual hormonal levels in feces or blood.
Treatment protocols for pathology have been attempted but need further
development (Radcliffe 2003). Simulation
or inducement of pregnancy may be the only prevention (Roth 2006; Hermes &
Hildebrandt 2011; Hermes et al. 2016; Roth et al. 2018). Females have been successfully assisted with
the maintenance of their pregnancies, and offspring have resulted. Other techniques are evolving quickly to
optimize production in this species (Galli et al. 2016) even though minimal and
marginal genetic material has been available. As happened with the Northern
White Rhino, soon there will be little genetic material left for preserving the
last record of the Sumatran Rhino (Saragusty et al.
2016; Nardelli 2019). The success of a single genetically distinct
union could revitalize this Critically Endangered species. None of these conditions will be identifiable
or treatable while animals are in the wild. Time is running out for younger
treatable animals, which without pregnancy are at risk of rapidly developing
pathology, given that Rosa developed pathology in less than five years.
Conclusion
The critically low estimates of numbers in
widely scattered populations of the Sumatran Rhino, coupled with the fact that
both captive populations and animals caught from the wild are largely
reproductively compromised, means that only a small number of reproductively
viable animals may be left in the wild.
In addition, the complete lack of relevant information, and in some
cases wild extrapolations, on the status of animals makes addressing these
problems in the wild impossible. In
light of these facts, building a new productive captive population by starting
immediately with capturing viable, productive animals from the onset and
optimizing their production is essential.
Recovery and use of vital genetic materials must be accelerated before
these resources are lost. Fertile
animals must be the first priority for the few sanctuary spaces that are
available. The best chance of obtaining
fertile founders exists in the few clusters where females with young have been
confirmed with recent camera-trap photos.
These will also be the areas where females are at risk of fewer pregnancies,
but may still be recoverable with treatment.
Only two such areas have provided such evidence: Way Kambas
National Park (Lampung, southern Sumatra) and certain areas of the Leuser ecosystem (Aceh, western Sumatra). They are the first focus areas for capturing
viable females, before they, too, are lost.
Table 1. Details of the female
Sumatran rhinoceros Dicerorhinus sumatrensis captured between 1984 and 2018 in Peninsula
Malaysia; Sabah, Borneo, East Malaysia; Sumatra, Indonesia and Kalimantan,
Borneo, Indonesia. The information includes (where available) date of capture,
date of death, given name, facility where kept, approximate age at time of
capture, and presence or absence of pathologies, method used and name of
examiner. The table includes data on 3 females born in captivity, as well as
data on a 2001 poached female found in Sabah.
|
Stud Book # |
Capture location |
Capture date |
Name |
Age at capture |
Captive facilities |
Date of death |
Evidence of copulation |
Evidence of pathology date
recorded |
Method |
Examiner |
|
01 |
Selangor, Malaysia |
30.iv.1984 |
Jeram |
Adult |
Melaka, Malaysia |
10.vii.2002 |
Yes |
Uterine Tumors
& Cysts (1991) |
Ultrasound |
N. Schaffer |
|
03 |
Malaysia |
18.iv.1985 |
Melintang |
N/A |
Melaka, Malaysia & Bangkok,
Thailand |
23.xi.1986 |
Unknown |
No Records |
|
|
|
05 |
Torgamba, Indonesia |
23.i.1986 |
Riau |
Adult |
Capture Site |
23.i.1986 |
Unknown |
No Records |
|
|
|
07 |
Johor, Malaysia |
10.ii.1986 |
Rima |
Adult |
Melaka, Malaysia |
12.iv.2003 |
Yes |
Birthed SB15 (1987); Cysts
(2001) |
Ultrasound |
R. Radcliffe |
|
10 |
Torgamba, Indonesia |
22.vi.1986 |
Subur |
Adult |
Port Lympne,
UK |
29.x.1986 |
No |
Uterine Leiomyoma |
Histology |
C. Furley |
|
11 |
Selangor, Malaysia |
6.vii.1986 |
Julia |
Adult |
Melaka, Malaysia |
15.xii.1989 |
No |
No Pathology |
Gross Pathology |
Z. Zahari |
|
12 |
Malaysia |
9.ix.1986 |
Dusun |
~10 Yrs. |
Melaka, Malaysia, Jakarta &
Way Kambas, Indonesia |
7.ii.2001 |
Yes |
Chronic Lactation (1992-2001); Irregular Uterus & Ovaries |
Ultrasound Histology |
N. Schaffer M. Agil |
|
13 |
Selangor, Malaysia |
25.ii.1987 |
Panjang |
~5 Yrs. |
Melaka, Malaysia |
9.xi.2003 |
Yes |
Uterine Cysts (1991); Tumors (2002) |
Ultrasound |
N. Schaffer R. Radcliffe |
|
15 |
Captive Born to SB07 in Melaka,
Malaysia |
23.v.1987 |
Minah |
N/A |
Melaka, Malaysia |
16.xi.2003 15YRS. |
Yes |
Cysts (2001) |
Ultrasound |
R. Radcliffe |
|
16 |
Selangor, Malaysia |
1.vii.1987 |
Seridelima |
~7 Yrs. |
Melaka, Malaysia |
23.ix.1988 |
No |
No Pathology |
Gross Pathology |
Z. Zahari |
|
18 |
Torgamba, Indonesia |
21.vii.1987 |
Meranti |
Adult |
Port Lympne,
UK |
4.xi.1994 |
No |
Uterine Leiomyoma (noted before
death in 1994) |
Histology |
C. Furley |
|
19 |
Malaysia |
26.viii.1987 |
Mas Merah |
~8 Yrs. |
Melaka, Malaysia |
17.xi.2003 |
Yes |
Few, Small Uterine Tumors & cysts (1991) Same Findings (2001) |
Ultrasound |
N. Schaffer R. Radcliffe |
|
22 |
Torgamba, Indonesia |
8.vii.1988 |
Dalu |
Adult |
Taman Safari, Indonesia |
27.vii.1993 |
Yes |
Multiple Corpus Luteum;
Enlarged Uterus (1993) |
Histology |
N. Schaffer M. Agil |
|
23 |
Pahang, Malaysia |
11.vii.1988 |
Seputih |
~10 Yrs. |
Melaka, Malaysia |
28.x.2003 |
Yes |
Uterine Cysts (1991); Large Tumor (1998); Tumors, Cysts
(2002) |
Ultrasound |
N. Schaffer R. Radcliffe |
|
24 |
Bengkulu, Indonesia |
22.vii.1988 |
Mahato |
Juvenile |
Los Angeles & Cincinnati,
USA |
10.v.1992 |
No |
Immature Reproductive Tract
(1992) |
Gross Pathology |
N. Schaffer |
|
25 |
Bengkulu, Indonesia |
24.vii.1988 |
Barakas |
~12 Yrs. |
San Diego, USA |
22.ii.1995 |
No |
Cystic endometrial hyperplasia
(1995) |
Histology |
L. Lowentine |
|
26 |
Lahad Datu,
Malaysia |
22.iv.1989 |
Lun Parai |
~6 Yrs. |
Sepilok, Sabah, Malaysia |
23.viii.2000 |
Yes |
Uterine Tumor
and cysts (1998) Leiomyoma (2001) |
Ultrasound Histology |
N. Schaffer |
|
27 |
Bengkulu, Indonesia |
26.viii.1989 |
Rapunzel |
~6 Yrs. |
Los Angeles & New York, USA |
22.xii.2005 |
No |
Uterine Tumors
and cysts (1994) |
Ultrasound |
N. Schaffer |
|
29 |
Bengkulu, Indonesia |
6.iii.1991 |
Emi |
~1 Yr. |
Los Angeles & Cincinnati,
USA |
5.ix.2009 |
Yes |
5 Abortions (1998 – 2001); 3
births (2001, 2004, 2007); Cysts (resolved) (2002) |
Ultrasound |
T. Roth |
|
32 |
Bengkulu, Indonesia |
17.v.1991 |
Bina |
~3 Yrs. |
Taman Safari & Way Kambas, Indonesia |
|
Yes |
Post productive (2010); Few cysts (2014); Cycling
(2019)? |
Ultrasound Ultrasound |
N. Schaffer T. Roth |
|
33 |
Bengkulu, Indonesia |
12.vi.1991 |
Rami |
~8 Yrs. |
San Diego, USA |
25.v.1992 |
Unknown |
No Records |
|
L. Lowentine |
|
34 |
Bengkulu, Indonesia |
17.i.1992 |
Wiwien |
~4 Yrs. |
Surabaya, Indonesia |
12.xi.1996 |
Unknown |
No Records |
|
|
|
40 |
Tabin, Malaysia |
17.vi.1994 |
Gologob |
Adult |
Sepilok, Sabah, Malaysia |
11.i.2014 |
Yes |
Few uterine cysts (1998); more
cysts (2004) Post productive (2010) |
Ultrasound Ultrasound |
N. Schaffer P. Kretzschmar |
|
|
Poached Animal Sabah, Malaysia |
2001 |
Female |
Adult |
Wild, Sabah |
N/A |
No |
Cysts and 3 Leiomyoma (2001) |
Histology |
N. Schaffer |
|
43 |
Captive Born to (SB29 +28)
Cincinnati, USA |
30.vii.2004 |
Suci |
N/A |
Cincinnati, USA |
30.iii.2014 |
No |
Immature |
|
|
|
45 |
Bukit Barisan
Selatan, Indonesia |
30.ix.2005 |
Rosa |
~3 YRS. |
Way Kambas,
Indonesia |
|
Yes |
Tumors & Cysts 5
years post cycling (2015); Early Embryo loss (2018) |
Ultrasound |
T. Roth |
|
46 |
Way Kambas,
Indonesia |
20.ix.2005 |
Ratu |
~5 YRS. |
Way Kambas,
Indonesia |
|
Yes |
2 Abortions (2009–2010); 2 Births (2012, 2016) |
Ultrasound |
T. Roth |
|
51 |
Tabin, Malaysia |
18.xii.2011 |
Puntung |
Adult |
Sabah, Malaysia |
15.vi.2017 |
No |
Multiple Uterine Cysts (2012) |
Ultrasound |
Z. Zahari |
|
57 |
Danum Valley, Malaysia |
10.iii.2014 |
Iman |
Adult |
Danum Valley, Sabah |
16.xi.2019 |
No |
Uterine Tumors
and Cysts (2014) |
Ultrasound |
Z. Zahari |
|
58 |
Captive Born to (SB42 + 46) Way
Kambas, Indonesia |
12.v.2016 |
Delilah |
N/A |
Way Kambas,
Indonesia |
|
No |
Immature |
|
|
|
|
Kutai Barat, Indonesia |
12.iii.2016 |
Najaq |
Old |
Died at Capture Site |
5.iv.2016 |
No |
No pathology, but ovaries and
uterus quiescent |
Gross Pathology |
M. Agil |
|
|
West Kutai,
Indonesia |
25.xi.2018 |
Pahu |
Old |
Kelian (Kalimantan)
Indonesia |
|
No |
Ovarian Tumor
(2019) |
Ultrasound |
M. Agil |
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