Behavioral and Spatial Analysis of a Symphalangus syndactylus Pair in a Controlled Environment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Ex situ conservation is an appropriate practice when its objectives are to promote recognition among the population of the existence of those representatives of wildlife that are at risk, as well as to allow studies that favor their conservation and well-being; This work achieves both, the readers of the work will be able to obtain a valid experience on how to achieve that life in captivity does not respond to the fulfillment of established patterns, but rather that each case requires studies on animal behavior, in this case in pairs, to favor conservation strategies, such as habitat enrichment by distinguishing the differences between individuals of the same species. Based on the above, I consider that the work should be published.

Author Response

Comment 1: Ex situ conservation is an appropriate practice when its objectives are to promote recognition among the population of the existence of those representatives of wildlife that are at risk, as well as to allow studies that favor their conservation and well-being; This work achieves both, the readers of the work will be able to obtain a valid experience on how to achieve that life in captivity does not respond to the fulfillment of established patterns, but rather that each case requires studies on animal behavior, in this case in pairs, to favor conservation strategies, such as habitat enrichment by distinguishing the differences between individuals of the same species. Based on the above, I consider that the work should be published.

Answer 1: Thank you for your thoughtful and encouraging feedback. We truly appreciate your recognition of the study’s significance and your insightful perspective on its contributions to conservation and animal welfare.

Reviewer 2 Report

Comments and Suggestions for Authors

See my comments inserted in the pdf of the manuscript (attached).

Comments for author File: Comments.pdf

Comments on the Quality of English Language

There are numerous mistakes and deficiencies in the quality of the English in this manuscript. These are extensively detailed in my comments that are inserted in the manuscript. A pervasive and recurring conceptual error was referring to "percentage" values (i.e., the percentage value of each behavioural category out of the total behavioural scans, for both the spring and fall observation periods, and for the entire entire study) as "frequencies". This is simply incorrect -- percentage values are not frequencies.

There were numerous minor compositional errors throughout the manuscript (e.g., things like "tense shifts" in the text -- such as starting a sentence in singular tense and then switching to plural tense part-way through the sentence). Individually these are small errors. But, when there are multiple compositional errors on just about every page of the manuscript, that significantly weakens the overall manuscript.

In places, I found that imprecise or inaccurate wording served to obscure the point(s) that the authors were trying to communicate. Clearer, more precise wording would have gone a long way towards addressing these compositional issues.

The authors sought to present the results of their observations on the siamang pair housed at the Wildlife Park "Le Cornelle" in the comparative context of previous behavioural research on siamangs both in the wild and in ex situ contexts. However, the list of References for the manuscript numbered just 24 sources. I would have thought that there would have been a longer list of relevant sources on aspects of siamang behaviour (be it either in the wild or in zoo settings). I think the authors should consider looking at incorporating additional reference sources into the manuscript. Additional comparative data could enable the authors to perhaps "solidify" some of their tentative interpretations of their behavioural data.

Author Response

Comment 1: There are numerous mistakes and deficiencies in the quality of the English in this manuscript. These are extensively detailed in my comments that are inserted in the manuscript. A pervasive and recurring conceptual error was referring to "percentage" values (i.e., the percentage value of each behavioural category out of the total behavioural scans, for both the spring and fall observation periods, and for the entire entire study) as "frequencies". This is simply incorrect -- percentage values are not frequencies.

Answer 1: Thank you for your valuable suggestions. We have carefully addressed all your comments and made the necessary revisions throughout the manuscript. In particular, we have corrected the misuse of the term "frequencies" when referring to percentage values, ensuring precise terminology.

Comment 2: There were numerous minor compositional errors throughout the manuscript (e.g., things like "tense shifts" in the text -- such as starting a sentence in singular tense and then switching to plural tense part-way through the sentence). Individually these are small errors. But, when there are multiple compositional errors on just about every page of the manuscript, that significantly weakens the overall manuscript.

Answer 2: Thank you for your insightful feedback. We have carefully reviewed the manuscript and corrected all compositional errors, including tense shifts and inconsistencies. These revisions have improved the clarity and coherence of the text.

Comment 3: In places, I found that imprecise or inaccurate wording served to obscure the point(s) that the authors were trying to communicate. Clearer, more precise wording would have gone a long way towards addressing these compositional issues.

Answer 3: Thank you for your valuable feedback. We have carefully revised the manuscript to improve clarity and precision, ensuring that our points are communicated accurately and effectively.

Comment 4: The authors sought to present the results of their observations on the siamang pair housed at the Wildlife Park "Le Cornelle" in the comparative context of previous behavioural research on siamangs both in the wild and in ex situ contexts. However, the list of References for the manuscript numbered just 24 sources. I would have thought that there would have been a longer list of relevant sources on aspects of siamang behaviour (be it either in the wild or in zoo settings). I think the authors should consider looking at incorporating additional reference sources into the manuscript. Additional comparative data could enable the authors to perhaps "solidify" some of their tentative interpretations of their behavioural data.

Answer 34 Thank you for your valuable feedback. We have added additional reference sources into the manuscript.

 

Comment 5: line 105: It would be a great aid for readers (for purposes of visualizing the exhibit) if you were to include a basic schematic diagram of the outdoor enclosure and how your coordinate system sub-divided the outdoor enclosure space into a grid system of cells.

Answer 5: line 105: Thank you for your helpful suggestion. The schematic diagram of the outdoor enclosure and its coordinate grid system is included in the supplementary materials.

Comment 6: line 156: Use of the term "planes" is potentially confusing and needs clarification -- e.g., a simple line drawing showing how the exhibit area was subdivided into cubic space. Use of the term "levels" would provide a clearer means of visualizing the use of space by the siamangs.

Answer 6: line 156: Thank you for your comment. We have revised the manuscript accordingly, replacing the term "planes" with "levels" to enhance clarity and improve the visualization of space use by the siamangs.

Comment 7: line 378: A diet high in leaves also increases resting behaviour as individuals digest their leafy meals.

Answer 7: line 378: Thank you for your insightful observation. You are absolutely correct that a diet high in leaves also increases resting behavior as individuals digest their meals. However, in this paragraph, we specifically focus on feeding behavior. In captivity, the percentage of time spent feeding is lower than in the wild, likely because captive individuals have guaranteed access to food, whereas wild individuals must invest more time in foraging. Additionally, since leaves have lower energy content, wild siamangs need to consume larger quantities to meet their daily nutritional requirements, further increasing their feeding time. For this reason, we did not discuss the relationship between leaf consumption and resting behavior in this section, as, when comparing captive and wild individuals, this factor does not significantly affect the overall percentage of resting time.

Comment 8: line 396: Was this the case at Wildlife Park "Le Cornelle"?

Answer 8: line 396: Yes, this is the case with at Wildlife Park “Le Cornelle”.

Comment 9: line 469: It is unclear what is being referred to here as, "... the percentage of the total data was 71.42%...". If vocalizations are being referred to, the figure of 71.42% appears inconsistent with the figure of 3.79% presented in Line 467.

Answer 9: line 469: Thank you for your comment. We acknowledge the lack of clarity in our previous statement and have revised the text accordingly. The percentage of 71.42% refers to the observation days in which at least one vocalization event occurred. Specifically, during this period, 71.42% of the observation days were characterized by one or more vocalizations, following the trend observed in the previous period. We have clarified this point in the manuscript to avoid any confusion.

Comment 10: line 488: Wording is unclear here -- what is the "previous case" to which you refer? Do you mean the first period of observations?

Answer 10: line 488: Thank you for your comment. We confirm that we were referring to the first period of observations. We have now clarified this in the text to improve readability and avoid ambiguity.

Comment 11: line 541: Wording of this closing phrase is unclear -- do you mean, "..., while the adjacent singing session durational categories were notably absent."?

Answer 11: line 541: Thank you for your comment. Yes, the intended meaning of the sentence is as you suggested. We have now modified the text accordingly to reflect your suggestion and improve clarity.

Comment 12: line 555: Why is there not a reference citation of Hosey here?

Answer 12: line 555: Thank you for your comment. We have now added the requested citation of Chamove et al. in the test.

Comment 13: line 570: “..Such as..?”

Answer 13: line 570: Thank you for your comment. We do not feel confident in speculating on the factors that may have influenced level preference. However, we believe this is an aspect that should be investigated by restoring the exhibit to its previous arrangement, thereby eliminating this key factor and allowing for a clearer assessment.

Comment 14: line 593: It would be good to provide a reference citation or two in order to support this distinction between "wellness" and "wellbeing".

Answer 14: line 593: Thank you for your valuable comment. We have now added a reference to support the distinction between "wellness" and "wellbeing," as per your suggestion. This addition strengthens the conceptual framework of our discussion and aligns with existing literature on animal welfare.

Reviewer 3 Report

Comments and Suggestions for Authors

This study aimed to analyse the behaviour, space use and vocalisation of a pair of 'Siamangs' (Symphalangus syndactylus) in a controlled environment. The study was conducted in the zoological park 'Le Cornelle' in Italy during two different periods to identify possible seasonal differences. The study analyses activity time and a survey of vocalisations and space use.

Studies of this type are complex because, as the authors quote in the introduction: 'The design of captive environments often aims to simulate or replicate aspects of the animals' natural habitats' (line 46). It is, therefore, difficult to analyse only the behaviour of animals in captivity and relate this to the wild population. However, researchers often have no other option, so the methodology adopted in the study is appropriate.

- The aim of the work and the hypotheses are clearly stated.

- The introduction is well written and based on current and appropriately selected literature. It presents the ecological background and the importance of the issue in the context of the conservation of an endangered species.

- The choice of research methods is appropriate. The ethogram is still an essential tool in animal behaviour research.

- The Chi-square test was used for statistical analysis, which is an appropriate tool for this type of research.

- The results are described in detail and presented in tables and figures.

- The article's conclusions are reasonable and in line with the study's objectives.

- The selection of sources is correct: 24 literature items were used in the article. The items in the literature list were correctly selected for the topics covered.

 

Weaknesses:

My caveat is the low abundance; it is difficult to infer from two individuals about the whole population. This weakness is due to the low access to individuals of this species living in captivity.

Any study of endangered species is essential, even if it is observations on a small number of individuals; therefore, I believe the paper is suitable for publication in J. Zool. Bot. Gard.

Author Response

Comment 1: This study aimed to analyse the behaviour, space use and vocalisation of a pair of 'Siamangs' (Symphalangus syndactylus) in a controlled environment. The study was conducted in the zoological park 'Le Cornelle' in Italy during two different periods to identify possible seasonal differences. The study analyses activity time and a survey of vocalisations and space use.

Studies of this type are complex because, as the authors quote in the introduction: 'The design of captive environments often aims to simulate or replicate aspects of the animals' natural habitats' (line 46). It is, therefore, difficult to analyse only the behaviour of animals in captivity and relate this to the wild population. However, researchers often have no other option, so the methodology adopted in the study is appropriate.

- The aim of the work and the hypotheses are clearly stated.

- The introduction is well written and based on current and appropriately selected literature. It presents the ecological background and the importance of the issue in the context of the conservation of an endangered species.

- The choice of research methods is appropriate. The ethogram is still an essential tool in animal behaviour research.

- The Chi-square test was used for statistical analysis, which is an appropriate tool for this type of research.

- The results are described in detail and presented in tables and figures.

- The article's conclusions are reasonable and in line with the study's objectives.

- The selection of sources is correct: 24 literature items were used in the article. The items in the literature list were correctly selected for the topics covered.

Weaknesses:

My caveat is the low abundance; it is difficult to infer from two individuals about the whole population. This weakness is due to the low access to individuals of this species living in captivity.

Any study of endangered species is essential, even if it is observations on a small number of individuals; therefore, I believe the paper is suitable for publication in J. Zool. Bot. Gard.

Answer 1: Thank you for your detailed and constructive feedback. We greatly appreciate your positive assessment of our study, particularly regarding the clarity of our objectives, the appropriateness of our methodology, and the relevance of our findings to conservation efforts.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

While the majority of my suggested revision were attended to, there remains a handful of revisions I called for that were *not* dealt with. These missed/ignored revisions have been highlighted.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

See my comment above about revisions that were *not* carried out. Thus, there are still a number of passages where the quality of the English could be improved.

Author Response

Comment 1: While the majority of my suggested revision were attended to, there remains a handful of revisions I called for that were *not* dealt with. These missed/ignored revisions have been highlighted.

Answer 1: Thank you for your valuable feedback. We have now incorporated the remaining suggested revisions into the manuscript.