Population Estimation of Proboscis Monkey (Nasalis larvatus) in Sarawak, Malaysia
Ahmad Fitri bin Aziz
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[The instrument was duly prepared by The Centre for Academic Information Services] Perpustakaan ToD Abdul Rahman Ya'kub UNIVERSITI MALAYSIA SARAWAK
Population Estimation of Proboscis Monkey (Nasalis larvatus) in Sarawak, Malaysia
.." '..
Ahmad Fitri bin Aziz
A thesis submitted In fulfilment of the requirement for the degree of Master of Science (Statistical Ecology)
Faculty of Resource Science and Technology UNIVERSITI MALAYSIASARAWAK 2019 DECLARATION
I hereby declare that this dissertation is entirely my original work except for quotations and citations which have been dully acknowledged. The thesis has not been accepted for any degree and is not concurrently submitted in candidature for any other degree .
. ,"'..
Ahmad F i tri Aziz
Faculty of Resource Science and Technology
UNIVERSITI MALAYSIA SARA W AK ACKNOWLEDGEMENT
Alhamdulillah, praise to Allah SWT for giving me the strength and with my faith upon
Him, I am able to hurdle through all the challenges and tasks in completing my research project from the first stage of preparing my research project until the final stage of publishing my research project. --...
I would like to express my sincere thanks to my principal supervisor, Associate Professor
Charlie Justin ak Mergie Laman and my co-supervisor, Dr Faisal Ali Anwarali Khan fQr their their untiring efforts, willingness to help by providing constant guidance, supervision, moral support and their precious time for discussions and field samplings throughout the course of this research project. I also like to thanks to Mr. Trevor Allen ak Nyaseng who helped me a lot during my sampling for almost two years.
I want to take this opportunity to thank my beloved parents, Mdm. Sharifah Rosmaliza
Sayed Zamri and Mr. Aziz Din for their ceaseless support and love. I would like to express my deepest gratitude to all my family members and siblings Nurul Azah, Nurul Azreen,
Nurul Fazilah and Nurul Husna. Lovely thanks to my fiance, Miss Nurul Atheerah
Shamsawi who is always on my side during the hard time. I am indebted to Mr Zahran f Mansor for being helpful and informative since our undergraduate study, may god bless him. A wholehearted appreciation goes to my colleagues especially to Miss Sally So
Kaicheen, Miss Melynda Cheok Ka Yi, Miss Pang Sing Tyan, Mr. Afifi Nazeri, Mr.
Ahmad Syahir Alias, Miss Elfieyra Syazana, Miss Thaqifah Syaza, Miss Aina Atira, Mr.
Qhairil Syamri, Mr. Julius William, Mr. Amsyari Morni and Mr Aidil Zahidin.
11 I would also like to thank to Sarawak Forestry Department and Sarawak Forestry
Corporation for granting research pennit (NCCD.907.4.4(JLD.13)-287) to conduct sampling in various localities in Sarawak. Also a special thanks to Ministry of Higher
Education (MOHE), Malaysia for providing scholarship for me under MyBrain15
Programme and supporting in funding of this research project under Fundamental of
Research Grant Scheme (FRGS/SG03(02)1l14112014(08». Last but nQt least, I offer my ".. regards and blessing to those all that I forgot to mention here.
III ABSTRACT
A central practical problem in ecology is the estimation of population size. Last published report on the state-wide survey and population estimation of proboscis monkey (Nasalis larvatus) in Sarawak was in 1987. In this study, survey on proboscis monkey population has been conducted at eight selected sites in Sarawak to update...;the estimation of population size and density of this species. This study have successfully estimated the overall population based on the forest types surveyed which had not been taken into account in any previous studies of proboscis monkey before. Boat survey technique was applied in all survey sites except in Bako National Park within a period of 17 months, starting from April 2015 until August 2016. A cumulative total of 618.6 km of riverbank and 24.14 km of line transect was surveyed. Out of eight surveyed sites, two sites show no presence of proboscis monkey which were Ulu Sebuyau National Park and Rajang
Mangrove National Park. A cumulative total of 860 individuals of proboscis monkey comprising of 105 groups was sighted from all surveyed sites. Three types of forests were identified from the eight surveyed sites where the proboscis monkeys were recorded which were mangrove forest, peat swamp forest and tropical heath forest with a sighted distribution of 527, 170 and 163 individuals, respectively. The total population estimation of proboscis monkey in all surveyed sites is 838 individuals. Maludam National, Park recorded the highest population estimation with 432 individuals. This was followed by
Bako National Park, Samunsam Wildlife Sanctuary, Kuching Wetland National Park,
Kuala Lawas Forest Reserve and Limbang Mangrove National Park with estimated population size of 105, 98, 82, 77 and 44 individuals, respectively. The overall population estimation of proboscis monkey in Sarawak based on the data from three types of forests
IV surveyed was 9,778 individuals. In mangrove forest, the population of proboscis monkey
was estimated to be 1,981 individuals with estimated population density of 1.25
2 individuals/km . In peat swamp forest, the population was estimated to be in the number of
2 6,174 individuals with estimated population density of 0.96 individuals/km . While in tropical heath forest, the population was estimated to be 1,623 individuals with 2.76 individualslkm2 of estimated popUlation density. There was no sign~ficant difference .," -. between the population density of proboscis monkeys and the forest types (F = 0.607, df =
2, P = 0.568). In addition, the popUlation sizes of proboscis monkeys in different forest types also did not show any significant difference (P = 0.353). A comparisons o! population estimates from different studies is complicated by their different method of analyses. A standard method of analysis, in lieu of using forest types in the estimation is needed, so that the population estimates and the changes in the population size of the proboscis monkeys can be systematically compared and monitored in the future.
Keywords: Sarawak, proboscis monkey, estimation, population size, population density.
v Anggaran Populasi Monyet Belanda (Nasalis larvatus) di Sarawak, Malaysia
ABSTRAK
Masalah praktikal utama dalam ekologi ialah anggaran saiz populasi. Laporan terakhir yang diterbitkan mengenai survei negeri dan anggaran populasi monyet belanda (Nasalis .,".. larvatus) di Sarawak adalah pada tahun 1987. Dalam kajian ini, survei tentang populasi monyet balanda telah dijalankan di lapan tapak terpilih di Sarawak untuk mengemaskini anggaran saiz populasi dan kepadatan populasi spesis ini. Kajian ini telah berjaya menganggarkan populasi keseluruhan berdasarkan jenis hutan yang disurvei yang tidak diambil kira dalam kajian monyet belanda sebelumnya. Teknik bot survei telah digunapakai di semua tapak survei kecuali di Taman Negara Bako dalam tempoh 17 bulan, bermula dari April 2015 hingga Ogos 2016. Sejumlah kumulatif 618.6 km tebing sungai dan 24.14 km transek talian telah disurvei. Daripada lapan tapak yang disurvei, dua tapak menunjukkan tiada kehadiran monyet belanda iaitu Taman Negara Ulu Sebuyau dan Taman Negara Paya Bakau Rajang. Jumlah kumulatif monyet balanda yang dilihat adalah 860 individu terdiri daripada 105 kumpulan daripada semua tapak yang dis urve i.
Tiga jenis hutan telah dikenalpasti dari semua tapak yang disurvei di mana monyet belanda direkodkan iaitu hutan paya bakau, hutan paya gambut dan hutan kerangas f dengan pengedaran sebanyak 527, 170 dan 163 individu, masing-masing. Jumlah anggaran populasi monyet belanda di semua tapak yang disurvei adalah 838 individu.
Taman Negara Maludam mencatatkan anggaran populasi tertinggi dengan 432 individu diikuti Taman Negara Bako, Santuari Hidupan Liar Samunsam, Taman Negara Wetland
Kuching, Hutan Simpan Kuala Lawas dan Taman Negara Paya Bakau Limbang dengan
VI anggaran popu/asi 105, 98, 82, 77 dan 44 individu, masing-masing. Anggaran keseluruhan populasi monyet belanda di Sarawak berdasarkan data dari tiga jenis hutan yang disurvei
adalah 9,778 individu. Di hutan paya bakau, populasi monyet f;elanda dianggarkan 1,981
2 individu dengan anggaran kepadatan populasi 1.25 individulkm . Di hutan paya gambut, popu/asi dianggarkan berjumlah 6,174 individu dengan kepadatan populasi 0.96 individulkrr/ Sementara di hutan kerangas, populasi dianggarkan 1,623 individu dengan .,,'•. kepadatan populasi 2.76 individulknl Tiada perbezaan yang signifikan antara kepadatan popu/asi monyet belanda danjenis hutan (F = 0.607, dk = 2, P = 0.568). Di samping itu, saiz population monyet belanda di jenis hutan yang berbeza juga tidak menunjukkan, perbezaan yang signifikan (P = 0.353). Perbandingan anggaran populasi monyet belanda dari kajian yang berlainan penuh dengan komplikasi disebabkan perbezaan kaedah analisis. Satu kaedah analisis yang standart, sebagai ganti dengan menggunakan jenis hutan dalam anggaran populasi diperlukan, supaya anggaran populasi dan perubahan saiz populasi monyet belanda dapat dibandingkan dan dipantau secara sistematik pada masa akan datang.
Kala kunci: Sarawak, monyet belanda, anggaran, saiz populasi, kepadatan populasi.
Vll PerpultakaaD Tun Abdul Rabman Y.'kub UN IVERS1TI MALAYSIA SARAWAK
T ABLE OF CONTENTS
Page
DECLARA TION
ACKNOWLEDGEMENT 1I
ABSTRACT lV
ABSTRAK . . ,1 ', Vl
TABLE OF CONTENTS Vlll
LIST OF TABLES Xli
LIST OF FIGURES XlV
ABBREVIATIONS xvi
CHAPTER 1: INTRODUCTION
1.1 General Introduction
1.2 Problem Statement 4
1.3 Objectives of Study 5
1.4 Hypothesis 5
CHAPTER 2: LITERATURE REVIEW 7
2.1 Morphology of Proboscis Monkey 7
2.2 General Biology and Ecology of Proboscis Monkey 8
2.2.1 Ranging Behaviour
2.2.2 Feeding Behaviour 10
2.3 Sleeping Site Selection 11
2.4 Social Organisation 13
2.5 Previous Survey and Estimation of Proboscis Monkey 14
2.6 Modelling Population Viability of Proboscis Monkey 17
Vlll CHAPTER 3: MATERIAL AND METHOD 19
3.1 Survey Sites 19
3.2 Survey Site Characteristic and Survey Route 21
3.2.1 Samunsam Wildlife Sanctuary 21
3.2.2 Kuching Wetland National Park 22
3.2.3 Bako National Park 23 .>'•. 3.2.4 Ulu Sebuyau National Park 25
3.2.5 Maludam National Park 26
3.2.6 Rajang Mangrove National Park 27
3.2.7 Limbang Mangrove National Park 28
3.2.8 Kuala Lawas Forest Reserve 29
3.3 Boat Survey and Line Transect Survey 30
3.4 Data Analysis 33
3.4.1 Population Density Estimation 33
3.4.2 Population Size Estimation 34
3.4.3 Overall Population Estimation for Whole Area of Sarawak 35
3.5 Vegetation Map and Forest Area Measurement 38
CHAPTER 4: RESULTS 39
4.1 Population Estimation 39
4.1.1 Samunsam Wildlife Sanctuary 39
4.1.2 Kuching Wetland National Park 42
4.1.3 Bako National Park 45
4.1.4 Ulu Sebuyau National Park 48
4.1.5 Maludam National Park 50
IX 4.1.6 Rajang Mangrove National Park 53
4.1.7 Limbang Mangrove National Park 54
4.1.8 Kuala Lawas Forest Reserve 57
4.2 Population Estimation of Proboscis Monkey in Sarawak 60
CHAPTER 5: DISCUSSION 65
5.1 Past and Present Estimation 65
..j! ' •• 5.2 Population Estimation in Survey Sites and Different Forest Types 67
5.3 Survey Technique Applied 71
5.4 Survey in Bako National Park 72
CHAPTER 6: CONCLUSION AND RECOMMENDATIONS 74
6.1 Conclusion 74
6.2 Recommendation 75
REFERENCES 76
APPENDICES 84
x LIST OF TABLES
Page
Table 3.1 List of surveyed sites with map point, study area (division), 20 area Slze, forest type, GPS coordinates and survey date (duration).
Table 4.1 Area distribution of vegetation in SWS. 39
Table 4.2 Estimated population size of proboscis monkey in SWS, 41
Table 4.3 Area distribution ofvegetation in KWNP. 43
Table 4.4 Estimated population size of proboscis monkey in KWNP. 44
Table 4.5 Area distribution of vegetation in BNP. 45
Table 4.6 Estimated population size ofproboscis monkey in BNP. 47
Table 4.7 Area distribution of vegetation in USNP. 48
Table 4.8 Area distribution ofvegetation in MNP. 51
Table 4.9 Estimated population size of proboscis monkey in MNP. 52
Table 4.10 Area distribution of vegetation in RMNP. 53
Table 4.11 Area distribution of vegetation in LMNP. 54
Table 4.12 Estimated population size ofproboscis monkey in LMNP. 56
Table 4.13 Area distribution of vegetation in KLFR. 57
Table 4.14 Estimated population size of proboscis monkey in KLFR. 59
Table 4.15 Estimated population size of proboscis monkey at various 61 localities in Sarawak. f Table 4.16 Estimated population size of proboscis monkey at various 63 vegetations in Sarawak
Table 4.17 Area distribution of vegetation in Sarawak. 64
xi LIST OF FIGURES
Page
Figure 3.1 Map of Sarawak showing survey areas. 1= §WS, 2= KWNP, 19 3= BNP, 4 = USNP, 5= MNP, 6= RMNP, 7= LMNP, 8= KLFR.
Figure 3.2 Survey route in SWS (source: Google Earth Pro 7.1.8.3036). 22
Figure 3.3 Survey route in KWNP (source: Google Earth Pro 7.1.8.3036). 23
.." '.. Figure 3.4 Survey route in BNP (source: Google Earth Pro 7.1.8.3036). 24
Figure 3.5 Survey route in USNP (source: Google Earth Pro 7.1.8.3036). 25
Figure 3.6 Survey route in MNP (source: Google Earth Pro 7.1.8.3036). 27
Figure 3.7 Survey route in RMNP (source: Google Earth Pro 7.1.8.3036). 28
Figure 3.8 Survey route in LMNP (source: Google Earth Pro 7.1.8.3036). 29
Figure 3.9 Survey route in KLFR (source: Google Earth Pro 7.1.8.3036). 30
Figure 3.10 Flow chart summarising the steps in population estimation 37 analysis of proboscis monkey in Sarawak.
Figure 4.1 Map showing vegetation types in SWS. 40
Figure 4.2 Map showing vegetation types in KWNP. 42
Figure 4.3 Map showing vegetation types in BNP. 46
Figure 4.4 Map showing vegetation types in USNP. 49.
Figure 4.5 Kumpai grass (Panicum sp.) blocked the entire river in USNP. 49
Figure 4.6 Map showing vegetation types in MNP. 50
Figure 4.7 Map showing vegetation types in RMNP. 56
Figure 4.8 Map showing vegetation types of LMNP. 55
Figure 4.9 Map showing vegetation types in KLFR. 58
Figure 4.10 Map of vegetation in Sarawak 64
xu LIST OF ABBREVIATIONS
BNP Balm National Park ca Circa CITES Convention on International Trade in Endangered Species of Wild Fauna and Flora groupslkm Groups per kilometre
. .,; 0, groUpS!km2 Groups per squared kilometre Ha Hectare individualslkm Individuals per kilometre individuals!km2 Individuals per square kilometre IUCN International Union for Conservation of Nature Kg Kilogram Km Kilometre km2 Square kilometre KLFR Kuala Lawas Forest Reserve KWNP Kuching Wetland National Park LMNP Limbang Mangrove National Park MF Mangrove forest MNP Maludam National Park PSF Peat swamp forest PVA Population Viability Analysis RMNP Rajang Mangrove National Park SWS Samunsam Wildlife Sanctuary THF Tropical heath forest USNP Ulu Sebuyau National Park
Xlll CHAPTER 1
INTRODUCTION
1.1 General Introduction
Endemic to the island of Borneo, proboscis monkey (Nasalis larvatus) is a large and " '.. sexually dimorphic primate from subfamily Colobinae (Bennett and Gombek, 1993). There is no fossil evidence showing proboscis monkey had occurred elsewhere other than in
Borneo (Harcourt and Schwartz, 2001; Harrison et al., 2006; Payne and Francis, 2007).
Proboscis monkey is distinctive from other primates due its large, red and protruding nose.
Within the subfamily Colobinae, proboscis monkey is categorised into the odd nosed monkey group where, none possess similar trait with proboscis monkey (Bennett and
Gombek, 1993). They are known to be the largest colobine monkey and the sole member from the genus Nasalis (Napier and Napier, 1967; Medway, 1977; Wolfheim, 1983).
The natural habitats of proboscis monkey are restricted to the lowland coastal rainforests including mangroves, riverine, peat and fresh water swamp forest that is always associated with waterways (Kawabe and Mano, 1972; Salter et al., 1985; Bennett and Gombek, 1993;
Meijaard and Nijman, 2000). Mangrove trees are the main features in the habitat where the trees are used for resting and sleeping, while the leaves serve as their food (Kawabe and
Mano, 1972). During the day, it will forage inland normally less than 1 km away from the riverbank and always return before dusk to sleep (Salter et al., 1985; Bennett and
Sebastian, 1988; Yeager, 1989; Matsuda et. al., 2008). Proboscis monkey has their own flexible social structure, for instance one-male with multi-female groups or all-male groups
1 (Bennett and Sebastian, 1988). Within several groups, a secondary level of social organisation may occur where they may travel and sleep together in close proximity
(Boonratana, 2002).
The proboscis monkey is protected by law throughout its range. In Sarawak, proboscis monkey is classified as a totally protected species under the SarawakWildlife Protection
Ordinance 1988. This primate is classified as endangered in the International Union for
Conservation of Nature (IUCN) Red List of Threatened Species (IUCN, 2017). In the
Convention on International Trade in Endangered Species of Wild Fauna and Flora
(CITES), this animal is listed in Appendix I. In the year of 2000, the status of this primate was changed from 'vulnerable' to 'endangered' (Meijaard et al., 2008). The combination of hunting, degradation of their habitats by the cause of logging and conversion into agricultural land were identified as the major impact of the declining population of this primate (Meijaard and Nijman, 2000).
In Kalimantan, Indonesia, there are huge differences on the estimations of population size of proboscis monkey. Based on the estimation by MacKinnon (1987), there are more than
250,000 individuals of proboscis monkey within Kalimantan and ca. 25,000 of them are live in protected areas. Yeager and Blondal (1992) suggested that there are less than 5,QOO individuals of proboscis monkey reserve in the protected area. Manansang et al. (2005) however suggested that the population of proboscis monkey in the Central, West and East
Kalimantan was 9,200 individuals. Proboscis monkey population in Kalimantan found to be more widely distributed compared to other regions in Borneo (Meijaard and Nijman,
2000).
2 In Sabah, based on the state-wide survey of proboscis monkey, the population were estimated to be at least 2,000 individuals (Davies and Payne, 1982). A more recent survey conducted by Sha et al. (2008) found that the population was gigher than that of recorded previously. The minimum of proboscis monkey population in Sabah were thought to be
5,907 individuals. Population of proboscis monkey in Sabah were found to be highly fragmented with only five major centres of continuous distribution and numerous small "'•. isolated populations along the major coastal river of Sabah including Klias Peninsula,
Tankarason, Paitan, Sugut, Beluran, Sandakan, Kinabatangan, Segama River, Lahad Datu,
Semporna Peninsula and Tawau Bay.
In contrast, the population of proboscis monkey in Sarawak was estimated to be less than
2,000 individuals (Salter and MacKenzie, 1985). A survey by Bennett et al. (1987) estimated that the population of proboscis monkey in Sarawak was less than 1,000 individuals. The distributions of proboscis monkey in Sarawak were widely distributed with a huge fragmentation, concentrated at the western part of the state (Salter and
MacKenzie, 1985). In Brunei, the population size of proboscis monkey in Brunei Bay was estimated to be less than 300 individuals (Bennett, 1986). However, the population in
Brunei Bay is homogenous with the population in Sarawak since it is located between the two divisions of Sarawak, which are Limbang and Lawas. The exact population of I proboscis monkey in Brunei Bay were difficult to detennine since they are known crossing into Sarawak.
3 1.2 Problem Statement
There are only a few localities where proboscis monkey are "known to occur in Sarawak including Bako National Park, Kuching Wetland National Park, Samunsam Wildlife
Sanctuary, Maludam National Park, Limbang Mangrove National Park and Kuala Lawas
Forest Reserve. Based on previous studies of proboscis monkey in Sarawak, most were ..~' ... focused on their behaviour and ecology (Salter et ai., 1985; Bennett and Sebastian, 1988;
Onuma, 2002; Tuen and Pandong, 2007; Pang et ai., 2007; Matsuda et ai., 2008; Kombi and Abdullah, 2013). Only a few studies have been conducted to estimates their population. Moreover, the estimations were always conducted in localities where proboscis monkey are well established, such as in Bako National Park and Samunsam Wildlife
Sanctuary (Brundell et ai., 1990; Zaini et. ai., 2004; Tuen and Pandong, 2007). A central practical problem in ecology is the estimation of population size (Krebs, 1989). However, this basic information has been ignored in the past, even though the population of proboscis monkey are known to be declining (Chapman and Peres, 200 1; Fuller et ai.,
2004). Till presently, the status of the proboscis monkey in Sarawak still depending on previous data (Salter and MacKenzie, 1985; Bennett et ai., 1987). Even though these estimates are known to be out-dated, they are still being cited until today. A population and habitat viability assessment in Indonesia by Manansang et al. (2005) was first planned to f cover the population of proboscis monkey for the entire range. However, basic data to draw up an accurate range maps and estimate population numbers were insufficient particularly for Malaysia Borneo. Without such information, it is impossible to formulate conservation plan to ensure the survival of proboscis monkey. In this study, a comprehensive and systematic state-wide survey of proboscis monkey population was
4 Pfrpustakaao TuaAbdul Rab DYa'kub lJNiVERSITl MALAYSIA SARAWAK conducted in Sarawak to estimate the population density and population size. The population estimation in this study were analysed based on the type of forests where the proboscis monkey were recorded. Data of the estimation popula90n density from each site were then extrapolated and being used as a representative data to estimate the population of proboscis monkey in each forest type surveyed. There are several assumptions need to be considered in this study. First, all the proboscis monkeys individuals have the same ..t" .. probability for being sighted due to the one-way of survey. Second, all proboscis monkeys individuals within 100 m radius were assumed to be in the same group. Third, the acreage of the forest types from the mapping analysis is considered to be accurate. Lastly, proboscis monkeys in Sarawak is assumed to inhabit only in mangrove, peat swamp and tropical heath forests. This study is important to provide a reliable and updated data in order to access the actual status of the current population of proboscis monkey in Sarawak.
1.3 Objectives of Study
The objectives ofthis study are:
I. To estimate the current popUlation density of proboscis monkey in Sarawak.
ll. To estimate the current population size of proboscis monkey in Sarawak.
1.4 Hypothesis
HOI: There is no significant difference between the population densities of proboscis
monkeys in different forest types.
5 HAl: There is significant difference between the population densities of proboscis
monkey in different forest types.
H02: There is no significant difference between the pORulation Sizes of proboscis ~
monkey in different forest types.
HAl: There is significant difference between the population densities . of proboscis
monkey in different forest types.
6 CHAPTER 2
LITERATURE REVIEW
2.1 Morphology of Proboscis Monkey
In the island of Borneo, there are three political divisions, which are bo1inded by Malaysia
(Sabah and Sarawak), Brunei and Indonesia (Kalimantan). Different communities in
Borneo named proboscis monkeys differently. In Sarawak, Dayak communities call
proboscis monkey as Rasong while Malay community calls it as Orang Belanda or Monyet
Belanda (Zaini et al., 2004). Communities in Sabah always known proboscis monkey as
Bayau. While in Kalimantan, proboscis monkey are often known as Benkantan (Zaini et
al.,2004).
Proboscis monkey possess a high degree of sexual dimorphism (Bennett, 1986). Between male and female, there are several obvious differences in the morphological appearance.
Adult male proboscis monkey larger than female with an average of 20-24 kg while female
is lighter than the male with an average half of the male weight, which is about 10-12 kg
(Bennett and Gombek, 1993; Phillipps and Phillipps, 2016). An adult male proboscis monkey can be easily identified by a large and pendulous nose. However, an adult femBle proboscis monkey has smaller and pointed nose. In both sexes, proboscis monkey has
reddish-brown fur but male display more striking colour with much thicker, darker mane of
hair across their back and have a darker cap on top of their head (Bennett and Gombek,
1993). In both sexes, proboscis monkey have a pair of webbed hind feet, which are likely
to aid in swimming and walking on mangrove mud (Harding, 2015). An infant proboscis
7