Cheryl Knott - Academia.edu (original) (raw)

Papers by Cheryl Knott

Current Biology, 2022

Conservation strategies are rarely systematically evaluated, which reduces transparency, hinders ... more Conservation strategies are rarely systematically evaluated, which reduces transparency, hinders the costeffective deployment of resources, and hides what works best in different contexts 1. Using data on the iconic and critically endangered orangutan (Pongo spp.), we developed a novel spatiotemporal framework for evaluating conservation investments. We show that around USD 1 billion was invested between 2000 and 2019 into orangutan conservation by governments, non-governmental organizations, companies and communities. Broken down by allocation to different conservation strategies, we find that habitat protection, patrolling and public outreach had the greatest return-on-investment for maintaining orangutan populations. Given variability in threats, land-use opportunity costs, and baseline remunerations in different regions, there were differential benefits-per-dollar invested across conservation activities and regions. We show that, while challenging from a data and analysis perspective, it is possible to fully understand the relationships between conservation investments and outcomes, and the external factors that influence these outcomes. Such analyses can provide improved guidance towards more effective biodiversity conservation. Insights into the spatiotemporal interplays between the costs and benefits driving effectiveness can inform decisions about the most suitable orangutan conservation strategies for halting population declines. While our study focuses on the three extant orangutan species of Sumatra and Borneo, our findings have broad application for evidence-based conservation science and practice worldwide 1 .

The impact of changing religious practices on orangutan fieldwork and conservation in W...

American Journal of Physical Anthropology, 2020

The juvenile risk aversion hypothesis suggests an extended life history is an adaptation to unpre... more The juvenile risk aversion hypothesis suggests an extended life history is an adaptation to unpredictable environments, such as those that characterize Bornean orangutans. We examined how changes in infant and juvenile activity budgets changed over time and with varying periods of food availability. We hypothesized that during periods of low food availability juvenile orangutans would trade-off developmentally important behavior, such as play, in order to conserve energetic resources. We tested this hypothesis using 924 follows of infant (0-4 years) and juvenile (5-8 years) orangutans, collected over a 25 year period, encompassing period fo high and low food availability at Gunung Palung National Park, Indonesia. Using a GLMM to control for individual and examining both age and food availability we found that overall, infant and juveniles played less during period of low food availability compared to medium and high food availability (b= -14.3, p < 0.0001) and that play behavior ...

Biological Conservation, 2021

Ecologists and conservation biologists conducting long-term research programs in the tropics must... more Ecologists and conservation biologists conducting long-term research programs in the tropics must confront serious ethical challenges that revolve around economic inequalities, cultural differences, supporting the local communities as much as possible, and sharing the knowledge produced by the research. In this collective article, researchers share their experiences and perspectives in dealing with the ethical issues that arise during research activities and cannot be ignored.

American Journal of Primatology, 2019

This commentary emerged from a panel presentation at the International Primatological Society Con... more This commentary emerged from a panel presentation at the International Primatological Society Congress in Nairobi, Kenya, 2018. The goal was to provide regional updates on the status of primate removal from habitat countries, especially for the pet trade, and develop guidelines that could help primatologists address this critical problem. The trade in live primates includes those used as pets, in entertainment, and as subjects of biomedical experimentation, but here we focus on those primates destined for the pet trade. Such transactions are a hugely lucrative business, impacting hundreds of thousands of individuals annually and affecting the survival of wild populations. Being intimately familiar with primate social behavior, life history and biology, primatologists, whether they work with captive or wild primates, are in a unique position to understand the nature of the trade and attempt to counter its effects. In addition to updating the status of the primate pet trade, we provid...

Journal of Human Evolution, 2018

Orangutans (Pongo spp.) are reported to have extremely slow life histories, including the longest... more Orangutans (Pongo spp.) are reported to have extremely slow life histories, including the longest average interbirth intervals of all mammals. Such slow life history can be viable only when unavoidable mortality is kept low. Thus, orangutans' survivorship under natural conditions is expected to be extremely high. Previous estimates of orangutan life history were based on captive individuals living under very different circumstances or on small samples from wild populations. Here, we combine birth data from seven field sites, each with demographic data collection for at least 10 years (range 12-43 years) on wild orangutans to better document their life history. Using strict criteria for data inclusion, we calculated infant survival, interbirth intervals and female age at first reproduction, across species, subspecies and islands. We found an average closed interbirth interval of 7.6 years, as well as consistently very high pre-weaning survival for males and females. Female survival of 94% until age at first birth (at around age 15 years) was higher than reported for any other mammal species under natural conditions. Similarly, annual survival among parous females is very high, but longevity remains to be estimated. Current data suggest no major life history differences between Sumatran and Bornean orangutans. The high offspring survival is remarkable, noting that modern human populations seem to have reached the same level of survival only in the 20th century. The orangutans' slow life history illustrates what can be achieved if a hominoid bauplan is exposed to low unavoidable mortality. Their high survival is likely due to their arboreal and non-gregarious lifestyle, and has allowed them to maintain viable populations, despite living in low-productivity habitats. However, their slow life history also implies that orangutans are highly vulnerable to a catastrophic population crash in the face of drastic habitat change.

Nature Ecology & Evolution

In humans, individuals’ social setting determines which and how language is acquired. Social secl... more In humans, individuals’ social setting determines which and how language is acquired. Social seclusion experiments show that sociality also guides vocal development in songbirds and marmoset monkeys, but absence of similar great ape data has been interpreted as support to saltational notions for language origin, even if such laboratorial protocols are unethical with great apes. Here we characterize the repertoire entropy of orangutan individuals and show that in the wild, different degrees of sociality across populations are associated with different ‘vocal personalities’ in the form of distinct regimes of alarm call variants. In high-density populations, individuals are vocally more original and acoustically unpredictable but new call variants are short lived, whereas individuals in low-density populations are more conformative and acoustically consistent but also exhibit more complex call repertoires. Findings provide non-invasive evidence that sociality predicts vocal phenotype i...

S were compared to chronological age. From ages 2 to 12, the MLE and chronological ages were not ... more S were compared to chronological age. From ages 2 to 12, the MLE and chronological ages were not significantly different, but differences increased at age 13, as previously shown. We adjusted the numerical parameters underlying the stages for developing teeth based on the combined sample, and results from testing with a modern forensic sample will be presented. This study shows that the Shackelford et al. method is applicable and accurate when aging subadults.

Orangutans have a 7.6 year average inter-birth interval, the longest of any mammal. Suckling occu... more Orangutans have a 7.6 year average inter-birth interval, the longest of any mammal. Suckling occurs throughout that interval, until the birth of the next offspring, but it is unclear how important milk consumption is during that period, as we cannot assess the actual intake amount. Measurement of stable carbon isotope ratios (d13C), stable nitrogen isotope ratios (d15N) and nitrogen content of feces (%N) provide evidence of the transition between breast milk to solid food. Here we present pilot data on these isotopic ratios from matched fecal samples of mothers and offspring (n=43), collected from wild orangutans in Gunung Palung National Park, Borneo, Indonesia. We found that the youngest infant (2.3 yrs) had the highest d15N values overall, indicative of a higher percentage of animal products (milk) in the diet. Older juveniles (5.8 yrs) did not consistently show higher d15N than their mothers. This may indicate variation in suckling frequency or the amount of breast milk consumed...

Dataset used for paper "An Energetic Explanation of Menstrual Taboos"Supporting documen... more Dataset used for paper "An Energetic Explanation of Menstrual Taboos"Supporting documentatio

Biological Conservation, 2021

Abstract The Gunung Palung Orangutan Project has conducted research on critically endangered wild... more Abstract The Gunung Palung Orangutan Project has conducted research on critically endangered wild Bornean orangutans (Pongo pygmaeus wurmbii) since 1994 in Gunung Palung National Park, West Kalimantan, Indonesia. A major goal of our broad-ranging research on orangutan behavior and ecology is to understand how the unique rainforest environment of Southeast Asia, characterized by dramatic changes in fruit productivity due to unpredictable mast fruiting, impacts orangutan behavior, physiology, and health. Much of our research has been devoted to the development of non-invasive techniques and an integrated biology approach – using hormonal assays, fecal processing, nutritional analysis, genetics, and behavioral ecology – and has led to an increased understanding of the ecological and evolutionary pressures shaping orangutan adaptations. Our results show that the extended life history and very slow reproductive rate of orangutans are adaptations to their environment. Orangutans in the Gunung Palung landscape, as elsewhere across Borneo and Sumatra, also face a series of conservation challenges, including extensive habitat loss and the illegal pet trade. We highlight how our investigations of orangutan health status, ecosystem requirements, and the assessment of orangutan density using ground and drone nest surveys have been applied to conservation efforts. We describe our project's direct conservation interventions of public education and awareness campaigns, sustainable livelihood development, establishment of village-run customary forests, investigation of the illegal pet trade, and active engagement with Indonesian government organizations. These efforts, in concert with the development of local scientific and conservation capacity, provide a strong foundation for further conservation as orangutans face a challenging future.

Scientific Reports, 2019

Infanticide as a male reproductive tactic is widespread across mammals, and is particularly preva... more Infanticide as a male reproductive tactic is widespread across mammals, and is particularly prevalent in catarrhine primates. While it has never been observed in wild orangutans, infanticide by non-sire males has been predicted to occur due to their extremely long inter-birth intervals, semi-solitary social structure, and the presence of female counter-tactics to infanticide. Here, we report on the disappearance of a healthy four-month-old infant, along with a serious foot injury suffered by the primiparous mother. No other cases of infant mortality have been observed at this site in 30 years of study. Using photographic measurements of the injury, and information on the behavior and bite size of potential predators, we evaluate the possible causes of this injury. The context, including the behavior of the female and the presence of a new male at the time of the injury, lead us to conclude that the most likely cause of the infant loss and maternal injury was male infanticide. We sug...

… Proceedings. The Apes …, 2001

OpenBU http://open.bu.edu Anthropology BU Open Access Articles 2019-10-21 Fecal temperature of wi... more OpenBU http://open.bu.edu Anthropology BU Open Access Articles 2019-10-21 Fecal temperature of wild and captive Bornean orangutans (Pongo pygmaeus wurmbii) a...

Nature Human Behaviour, 2017

Why did our ancestors combine the first consonant-and vowel-like utterances to produce the first ... more Why did our ancestors combine the first consonant-and vowel-like utterances to produce the first syllable or word? To answer this question, it is essential to know what constituted the communicative function of proto-consonants vs. proto-vowels before their combined use became universal. Close to nothing is known, however, about consonant-like calls in the primate order 1,2. Here, we investigate a large collection of voiceless consonant-like calls in nonhuman great apes-our closest relatives-namely orangutans (Pongo spp.). We analyzed 4486 kiss-squeaks collected across 48 individuals in four wild populations. Despite idiosyncratic production mechanics, consonant-like calls displayed informationdense content and the same acoustic signatures found in nonhuman primate voiced vowel-like calls, implying similar biological functions. Selection regimes between proto-consonants and-vowels were, thus, probably indistinguishable at the dawn of spoken language evolution. Our findings suggest that the first protosyllables or-words in our lineage probably constituted message reiterations, instead of messages of increasing intricacy. Primate vocal behavior is a cornerstone in the theory of speech evolution 3. Vocal homologies between human and nonhuman primates provide potential paths for the evolution of spoken language in humans 4 and several vocal traits exhibit evolutionary continuity between human and nonhuman primate (hereafter primate) vocal systems 5. Primate literature has hitherto focused almost exclusively on primate voiced calls, or "vocalizations". That is, utterances that feature vocal fold action, namely vocal folds' regular oscillation as sound source 6. Voiced calls characterize primate, and indeed mammalian repertoires as a whole, and they survive today in human speech predominantly in the form of vowels (as well as non-linguistic utterances, such as laughter and crying). Accordingly, voiced calls likely date back to a mammalian ancestor that lived some 125 million-years-ago 7 , 80Mya before the last common ancestor of all primates, some 45Mya 8. Marginal theoretical attention and empirical effort have, however, been dedicated to voiceless calls 9,10. Voiceless calls (e.g. smacks, clicks, raspberries), unlike their voiced counterparts, do not result from vocal fold action but instead from supra-laryngeal maneuvering. This feature renders them homologous in terms of articulation and acoustics to voiceless utterances in humans, which primarily function Contributions AL conceived and designed the study. AL, RV, AA and MH collected data. AL, RV, AA and MH analyzed data. AL, GC, CK, SW contributed materials/data collection and analysis tools. AL, GC, CK, SW and MH wrote the manuscript.

Current Biology, 2022

Conservation strategies are rarely systematically evaluated, which reduces transparency, hinders ... more Conservation strategies are rarely systematically evaluated, which reduces transparency, hinders the costeffective deployment of resources, and hides what works best in different contexts 1. Using data on the iconic and critically endangered orangutan (Pongo spp.), we developed a novel spatiotemporal framework for evaluating conservation investments. We show that around USD 1 billion was invested between 2000 and 2019 into orangutan conservation by governments, non-governmental organizations, companies and communities. Broken down by allocation to different conservation strategies, we find that habitat protection, patrolling and public outreach had the greatest return-on-investment for maintaining orangutan populations. Given variability in threats, land-use opportunity costs, and baseline remunerations in different regions, there were differential benefits-per-dollar invested across conservation activities and regions. We show that, while challenging from a data and analysis perspective, it is possible to fully understand the relationships between conservation investments and outcomes, and the external factors that influence these outcomes. Such analyses can provide improved guidance towards more effective biodiversity conservation. Insights into the spatiotemporal interplays between the costs and benefits driving effectiveness can inform decisions about the most suitable orangutan conservation strategies for halting population declines. While our study focuses on the three extant orangutan species of Sumatra and Borneo, our findings have broad application for evidence-based conservation science and practice worldwide 1 .

The impact of changing religious practices on orangutan fieldwork and conservation in W...

American Journal of Physical Anthropology, 2020

The juvenile risk aversion hypothesis suggests an extended life history is an adaptation to unpre... more The juvenile risk aversion hypothesis suggests an extended life history is an adaptation to unpredictable environments, such as those that characterize Bornean orangutans. We examined how changes in infant and juvenile activity budgets changed over time and with varying periods of food availability. We hypothesized that during periods of low food availability juvenile orangutans would trade-off developmentally important behavior, such as play, in order to conserve energetic resources. We tested this hypothesis using 924 follows of infant (0-4 years) and juvenile (5-8 years) orangutans, collected over a 25 year period, encompassing period fo high and low food availability at Gunung Palung National Park, Indonesia. Using a GLMM to control for individual and examining both age and food availability we found that overall, infant and juveniles played less during period of low food availability compared to medium and high food availability (b= -14.3, p < 0.0001) and that play behavior ...

Biological Conservation, 2021

Ecologists and conservation biologists conducting long-term research programs in the tropics must... more Ecologists and conservation biologists conducting long-term research programs in the tropics must confront serious ethical challenges that revolve around economic inequalities, cultural differences, supporting the local communities as much as possible, and sharing the knowledge produced by the research. In this collective article, researchers share their experiences and perspectives in dealing with the ethical issues that arise during research activities and cannot be ignored.

American Journal of Primatology, 2019

This commentary emerged from a panel presentation at the International Primatological Society Con... more This commentary emerged from a panel presentation at the International Primatological Society Congress in Nairobi, Kenya, 2018. The goal was to provide regional updates on the status of primate removal from habitat countries, especially for the pet trade, and develop guidelines that could help primatologists address this critical problem. The trade in live primates includes those used as pets, in entertainment, and as subjects of biomedical experimentation, but here we focus on those primates destined for the pet trade. Such transactions are a hugely lucrative business, impacting hundreds of thousands of individuals annually and affecting the survival of wild populations. Being intimately familiar with primate social behavior, life history and biology, primatologists, whether they work with captive or wild primates, are in a unique position to understand the nature of the trade and attempt to counter its effects. In addition to updating the status of the primate pet trade, we provid...

Journal of Human Evolution, 2018

Orangutans (Pongo spp.) are reported to have extremely slow life histories, including the longest... more Orangutans (Pongo spp.) are reported to have extremely slow life histories, including the longest average interbirth intervals of all mammals. Such slow life history can be viable only when unavoidable mortality is kept low. Thus, orangutans' survivorship under natural conditions is expected to be extremely high. Previous estimates of orangutan life history were based on captive individuals living under very different circumstances or on small samples from wild populations. Here, we combine birth data from seven field sites, each with demographic data collection for at least 10 years (range 12-43 years) on wild orangutans to better document their life history. Using strict criteria for data inclusion, we calculated infant survival, interbirth intervals and female age at first reproduction, across species, subspecies and islands. We found an average closed interbirth interval of 7.6 years, as well as consistently very high pre-weaning survival for males and females. Female survival of 94% until age at first birth (at around age 15 years) was higher than reported for any other mammal species under natural conditions. Similarly, annual survival among parous females is very high, but longevity remains to be estimated. Current data suggest no major life history differences between Sumatran and Bornean orangutans. The high offspring survival is remarkable, noting that modern human populations seem to have reached the same level of survival only in the 20th century. The orangutans' slow life history illustrates what can be achieved if a hominoid bauplan is exposed to low unavoidable mortality. Their high survival is likely due to their arboreal and non-gregarious lifestyle, and has allowed them to maintain viable populations, despite living in low-productivity habitats. However, their slow life history also implies that orangutans are highly vulnerable to a catastrophic population crash in the face of drastic habitat change.

Nature Ecology & Evolution

In humans, individuals’ social setting determines which and how language is acquired. Social secl... more In humans, individuals’ social setting determines which and how language is acquired. Social seclusion experiments show that sociality also guides vocal development in songbirds and marmoset monkeys, but absence of similar great ape data has been interpreted as support to saltational notions for language origin, even if such laboratorial protocols are unethical with great apes. Here we characterize the repertoire entropy of orangutan individuals and show that in the wild, different degrees of sociality across populations are associated with different ‘vocal personalities’ in the form of distinct regimes of alarm call variants. In high-density populations, individuals are vocally more original and acoustically unpredictable but new call variants are short lived, whereas individuals in low-density populations are more conformative and acoustically consistent but also exhibit more complex call repertoires. Findings provide non-invasive evidence that sociality predicts vocal phenotype i...

S were compared to chronological age. From ages 2 to 12, the MLE and chronological ages were not ... more S were compared to chronological age. From ages 2 to 12, the MLE and chronological ages were not significantly different, but differences increased at age 13, as previously shown. We adjusted the numerical parameters underlying the stages for developing teeth based on the combined sample, and results from testing with a modern forensic sample will be presented. This study shows that the Shackelford et al. method is applicable and accurate when aging subadults.

Orangutans have a 7.6 year average inter-birth interval, the longest of any mammal. Suckling occu... more Orangutans have a 7.6 year average inter-birth interval, the longest of any mammal. Suckling occurs throughout that interval, until the birth of the next offspring, but it is unclear how important milk consumption is during that period, as we cannot assess the actual intake amount. Measurement of stable carbon isotope ratios (d13C), stable nitrogen isotope ratios (d15N) and nitrogen content of feces (%N) provide evidence of the transition between breast milk to solid food. Here we present pilot data on these isotopic ratios from matched fecal samples of mothers and offspring (n=43), collected from wild orangutans in Gunung Palung National Park, Borneo, Indonesia. We found that the youngest infant (2.3 yrs) had the highest d15N values overall, indicative of a higher percentage of animal products (milk) in the diet. Older juveniles (5.8 yrs) did not consistently show higher d15N than their mothers. This may indicate variation in suckling frequency or the amount of breast milk consumed...

Dataset used for paper "An Energetic Explanation of Menstrual Taboos"Supporting documen... more Dataset used for paper "An Energetic Explanation of Menstrual Taboos"Supporting documentatio

Biological Conservation, 2021

Abstract The Gunung Palung Orangutan Project has conducted research on critically endangered wild... more Abstract The Gunung Palung Orangutan Project has conducted research on critically endangered wild Bornean orangutans (Pongo pygmaeus wurmbii) since 1994 in Gunung Palung National Park, West Kalimantan, Indonesia. A major goal of our broad-ranging research on orangutan behavior and ecology is to understand how the unique rainforest environment of Southeast Asia, characterized by dramatic changes in fruit productivity due to unpredictable mast fruiting, impacts orangutan behavior, physiology, and health. Much of our research has been devoted to the development of non-invasive techniques and an integrated biology approach – using hormonal assays, fecal processing, nutritional analysis, genetics, and behavioral ecology – and has led to an increased understanding of the ecological and evolutionary pressures shaping orangutan adaptations. Our results show that the extended life history and very slow reproductive rate of orangutans are adaptations to their environment. Orangutans in the Gunung Palung landscape, as elsewhere across Borneo and Sumatra, also face a series of conservation challenges, including extensive habitat loss and the illegal pet trade. We highlight how our investigations of orangutan health status, ecosystem requirements, and the assessment of orangutan density using ground and drone nest surveys have been applied to conservation efforts. We describe our project's direct conservation interventions of public education and awareness campaigns, sustainable livelihood development, establishment of village-run customary forests, investigation of the illegal pet trade, and active engagement with Indonesian government organizations. These efforts, in concert with the development of local scientific and conservation capacity, provide a strong foundation for further conservation as orangutans face a challenging future.

Scientific Reports, 2019

Infanticide as a male reproductive tactic is widespread across mammals, and is particularly preva... more Infanticide as a male reproductive tactic is widespread across mammals, and is particularly prevalent in catarrhine primates. While it has never been observed in wild orangutans, infanticide by non-sire males has been predicted to occur due to their extremely long inter-birth intervals, semi-solitary social structure, and the presence of female counter-tactics to infanticide. Here, we report on the disappearance of a healthy four-month-old infant, along with a serious foot injury suffered by the primiparous mother. No other cases of infant mortality have been observed at this site in 30 years of study. Using photographic measurements of the injury, and information on the behavior and bite size of potential predators, we evaluate the possible causes of this injury. The context, including the behavior of the female and the presence of a new male at the time of the injury, lead us to conclude that the most likely cause of the infant loss and maternal injury was male infanticide. We sug...

… Proceedings. The Apes …, 2001

OpenBU http://open.bu.edu Anthropology BU Open Access Articles 2019-10-21 Fecal temperature of wi... more OpenBU http://open.bu.edu Anthropology BU Open Access Articles 2019-10-21 Fecal temperature of wild and captive Bornean orangutans (Pongo pygmaeus wurmbii) a...

Nature Human Behaviour, 2017

Why did our ancestors combine the first consonant-and vowel-like utterances to produce the first ... more Why did our ancestors combine the first consonant-and vowel-like utterances to produce the first syllable or word? To answer this question, it is essential to know what constituted the communicative function of proto-consonants vs. proto-vowels before their combined use became universal. Close to nothing is known, however, about consonant-like calls in the primate order 1,2. Here, we investigate a large collection of voiceless consonant-like calls in nonhuman great apes-our closest relatives-namely orangutans (Pongo spp.). We analyzed 4486 kiss-squeaks collected across 48 individuals in four wild populations. Despite idiosyncratic production mechanics, consonant-like calls displayed informationdense content and the same acoustic signatures found in nonhuman primate voiced vowel-like calls, implying similar biological functions. Selection regimes between proto-consonants and-vowels were, thus, probably indistinguishable at the dawn of spoken language evolution. Our findings suggest that the first protosyllables or-words in our lineage probably constituted message reiterations, instead of messages of increasing intricacy. Primate vocal behavior is a cornerstone in the theory of speech evolution 3. Vocal homologies between human and nonhuman primates provide potential paths for the evolution of spoken language in humans 4 and several vocal traits exhibit evolutionary continuity between human and nonhuman primate (hereafter primate) vocal systems 5. Primate literature has hitherto focused almost exclusively on primate voiced calls, or "vocalizations". That is, utterances that feature vocal fold action, namely vocal folds' regular oscillation as sound source 6. Voiced calls characterize primate, and indeed mammalian repertoires as a whole, and they survive today in human speech predominantly in the form of vowels (as well as non-linguistic utterances, such as laughter and crying). Accordingly, voiced calls likely date back to a mammalian ancestor that lived some 125 million-years-ago 7 , 80Mya before the last common ancestor of all primates, some 45Mya 8. Marginal theoretical attention and empirical effort have, however, been dedicated to voiceless calls 9,10. Voiceless calls (e.g. smacks, clicks, raspberries), unlike their voiced counterparts, do not result from vocal fold action but instead from supra-laryngeal maneuvering. This feature renders them homologous in terms of articulation and acoustics to voiceless utterances in humans, which primarily function Contributions AL conceived and designed the study. AL, RV, AA and MH collected data. AL, RV, AA and MH analyzed data. AL, GC, CK, SW contributed materials/data collection and analysis tools. AL, GC, CK, SW and MH wrote the manuscript.