PONE-D-23-31488Maximum trunk tip force assessment related to trunk position and prehensile 'fingers' implication in African savannah elephantsPLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: No

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Strong aspects:

The authors measure the force of the fingers of the trunk of several elephants and find out that one finger has stronger force than the other.

Weak aspects:

Although the findings are new the possible implications or applications of this particularity of the elephant trunk are not mentioned. I suggest to improve of the paper by giving possible reasons why the dorsal finger is more powerful. Also, a comparison with the human hand would be interesting.

Comments

The latin name for this specie of elephant is given twice: at the beginning of the paper and around line 200.

Reviewer #2: This manuscript measures the distal gripping force of female African savanna elephants through a cleverly designed experiment on captive individuals. The study is able to display interesting results related to maximum pinch force, as well as differences between the two fingers of the trunk. I enjoyed reading the manuscript but I do think that it requires more polishing before acceptance. Please see my comments below. I also suggest that the manuscript is proof read for the English, as some sections were either a little difficult to make sense of, or words such as "Indeed" are over-used. I hope that my comments will be helpful in improving your manuscript. Well done.

Please be careful with your changing of tenses within sections. I have pointed it out a couple times in the Methods but I see it happening in the Results as well.

Introduction

Page 3, line 48: Scientific name for Asian elephants can be mentioned earlier in the Intro when you first mention them.

Methods

Page 5, line 101: Change to "and then in April 2023."

Page 5, line 102: no need to re-mention the scientific name here.

Table 1: Rather add a column heading for birth year and a column heading for birth location. Then the Origin column can be divided into these 2 columns to make for easier reading.

Page 5, line 106: Rather say "In this study, we observed elephants in an indoor setting."

Page 5, lines 106-108: Please rephrase the English of the second sentence of this paragraph.

Page 6, lines 118-127: Stick to the same tense for the paragraph. Here it changes from present to past tense. The same goes for the "The Course of the Experiment" paragraph.

Page 6, line 122: Change to "pinch hard enough to pass..."

Page 8, lines 180-183: Please combine these sentences with a comma.

Page 9, line 192: Rather say "as previously mentioned."

Table 2: I think that Table 2 can be made more clear to the reader. Look at splitting the 3rd and 4th columns into subheadings where the value is placed below. The current state makes it difficult to understand and appreciate the variation of the recorded values.

Results

Page 10, line 204: Rather say "summarised" instead of "summed up"

Page 11, lines 216-218: Even though the p values are shown in the graph, please provide the full statistics here and the average force values.

Page 11, lines 228-229: Give the average values if you can here.

Page 11, line 230: What do you mean more important? Do you mean greater?

Page 12, lines 241-244: Here in brackets you can actually put what the maximum bent and unbent values were. E.g. - (??N bent vs ??N unbent).

Figure 6 - Instead of placing the full p-values for all of your figures, rather use the *, **, *** code system representing p<0.05; 0.01; 0.001. It will help neaten the figures.

Page 13, lines 272-273: Please correct the English of this sentence.

Page 14, line 285: Again, rather rephrase the word "important" to something of increased or decreased

Discussion

Page 14, line 294: The lower force recorded by your study? Please be specific.

Page 14, line 299: Remove "we know" - the audience may not know.

Page 14, lines 304-305: Remove "On one hand" and then instead of saying "Our hypothesis was wrong", rather add "disproving our hypothesis" to the end of the first sentence.

Page 15, line 313: Remove "On the other hand"

Page 15, line 319: The word "Indeed" is used a lot in the Discussion. Try substitute it for other words of the same meaning.

Page 15, line 327: Remove "All pinches combined"

Page 15, line 328: Change is to was

Page 16, lines 399-355: Please try and rewrite this paragraph in a more concise manner. It feels very long-winded and I am sure could be reduced into a more concise description.

I noticed that you spoke about robotics extensively in the Introduction, which lead me to believe that the Discussion would loop back to this, however, robotics is never mentioned in the Discussion. I suggest either cutting down its portion in the Intro drastically, or show here in the Discussion how what you have found relates back to robotics.

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Reviewer #1: No

Reviewer #2: No

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Maximum trunk tip force assessment related to trunk position and prehensile fingers implication in African savannah elephants

PONE-D-23-31488R1

Dear Dr. Costes,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Monika Błaszczyszyn

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors responded to all my comments. The main comment related to the diference between the elephant fingers force and comparison with the human hand was addresed rigorously by improving the state of the art. I have no further comments.

Reviewer #2: Thank you for the corrections and well done. I am happy that all of my comments have been adhered to and the manuscript looks ready for publishing.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

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