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Dear Dr. Mata,
I am pleased to inform you that your revised manuscript, "Cavy lifespan: survival analysis and lifetables for the pet guinea pig (Cavia porcellus, L.) in Britain", has been accepted for publication.
[# PeerJ Staff Note - this decision was reviewed and approved by Jennifer Vonk, a PeerJ Section Editor covering this Section #]
Dear Dr. Mata,
Your revised manuscript titled "Cavy lifespan: survival analysis and lifetables for the pet guinea pig (Cavia porcellus, L.) in Britain" was reviewed by two expert reviewers and based on their opinions and my review, the decision is “Minor Revisions”.
Please address my point (presentation of survival data).
Author response: I understand your point; however, please note: In survival analysis, data is provided in a unit with decimals. I understand it could be useful for the reader to have these in years, months, and days; however, for comparison of lifespan with other studies, these units are not used. Data is commonly reported in years with decimals.
Editor: While I understand that survival analysis is provided in decimal units, as the author himself stated: “… it could be useful for the reader to have these in years, months, and days”. Please add the requested information (i.e., the mean lifespan - 4 years and 8 days) at least in the results section (L133): e.g., “The mean lifespan of the British guinea pigs in the analysed dataset is 4.022 years (4 years and 8 days) with 95% confidence interval…”
Dear Dr. Mata,
Your revised manuscript titled "Cavy lifespan: survival analysis and lifetables for the pet guinea pig (Cavia porcellus, L.) in Britain" was reviewed by two expert reviewers and based on their opinions and my review, the decision is “Minor Revisions”.
Please carefully read the reviewers’ comments and address them fully in your revised manuscript. In addition, regarding my previous point (presentation of survival data) - While I understand your response, please add the requested information (i.e., the mean lifespan - 4 years and 8 days) at least in the results section (L133): “The mean lifespan of the British guinea pigs in the analysed dataset is 4.022 years (4 years and 8 days) with 95% confidence interval…”
Please ensure that all review, editorial, and staff comments are addressed in a response letter and any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.
Please note that submitting a revision of your manuscript does not guarantee eventual acceptance, and that your revision may be subject to re-review by the reviewer(s) before a decision is rendered.
The basic reporting of the study is fine. I personally feel that some of the technical terms around the survival analysis (e.g. censored entries) should be explained. I appreciate that readers who are familiar with the analysis are likely to know about this, but some readers might not be so familiar. I also feel that the background/rationale still could have less on the domestication aspect and more of the causes of morbidity and mortality in guinea pigs as I suggested (as did the other reviewers from what I can see in the response document). I appreciate some content has been added on this, but I feel this should be a greater focus in the introduction.
No comment.
I feel the findings are valid and there is some useful interpretation, especially with the edits to the manuscript. However, I still feel the part in the discussion about pregnancy has less applicability as I don't think pet owners are likely to be breeding their guinea pigs.
Thank you for making amendments to this manuscript, I think these changes have definitely improved it. I personally feel there are some areas that could still benefit from further changes as mentioned in the sections above.
Please check the grammar. E.g.:
line 45: healing practices (d(deFrance, 2021)
line 76: improved guinea pigs’ not improved guinea pigs
line 83-84: program not programme
No remarks.
No remarks.
No remarks.
Dear Dr. Mata,
Your manuscript titled "Cavy lifespan: survival analysis and lifetables for the pet guinea pig (Cavia porcellus, L.) in Britain" was considered by two expert reviewers and based on their opinions and my review, the decision is “Major Revisions”.
Please carefully read the reviewers’ comments and address them fully in your revised manuscript. In addition, please address the following points:
I'll rewrite these review points into a more constructive and polished format:
(1) Presentation of Survival Data: Consider expressing survival times in a more intuitive format combining years with months or days. For instance, "4 years and 8 days" provides better clarity than the decimal format "4.022 years," making the results immediately comprehensible to readers.
(2) Introduction Balance: The current introduction dedicates excessive space (approximately 80%) to guinea pig domestication history. Consider condensing this historical context into one concise paragraph and expanding on relevant previous research about guinea pig lifespans to provide a more appropriate foundation for your study.
(3) Numerical Accuracy: There appears to be a calculation error in Table 1 regarding breed numbers. The sum of (627) and (47) equals 674, not 664 as currently reported. Please verify and correct this discrepancy.
(4) Study Limitations: Consider acknowledging these additional limitations:
(i) The absence of cause-of-death analysis, which could provide valuable insights into lifespan factors
(ii) No consideration of potential cohort effects (guinea pigs born in different years may have experienced varying husbandry practices)
(iii) Lack of geographical analysis within Britain that might reveal regional variations in care practices affecting longevity
Please ensure that all review, editorial, and staff comments are addressed in a response letter and any edits or clarifications mentioned in the letter are also inserted into the revised manuscript where appropriate.
Please note that submitting a revision of your manuscript does not guarantee eventual acceptance, and that your revision may be subject to re-review by the reviewer(s) before a decision is rendered.
Line 74 – I wonder if this should be ‘advancements in pet care have improved guinea pigs' wellbeing’ rather than ‘their’
Line 79 – should be ‘and Japanese quail’?
Line 83 – I think it would be helpful to give more detail of the findings of O’Neill et al., 2024 despite the discrepancy in the exact variables examined compared to the current study.
The introduction provides a nice overview of the background and domestication of guinea pigs but not much about their husbandry requirements or common pathologies. Given the study is about survival, I would have expected some coverage of the types of conditions that guinea pigs would usually suffer from and how their husbandry when kept as pets can predispose these problems (you might be able to link nicely back in with some of the content on their ecology and how they existed in the wild?). Could you include some of the lifespan data reported in the literature?
Line 97 – should this be ‘stated’ rather than ‘state’?
Line 97 – there are no censored entries – what does this mean?
Line 98 – 101 = this seems more like results/discussion of the findings than methods?
The results section is quite brief (I know you have the tables) are there any other descriptive statistics that would be useful to report on? I think where you refer to the tables (e.g. line 126) I think it should be ‘values can be found in table 3’ rather than ‘can be consulted in table 3’
Line 131 – I think this sentence lacks clarity and should read ‘The survivability of the pet guinea pig has never been studied before’.
Line 143-144 – This sentence is a bit confusing and would benefit from re-phrasing.
Line 149 – 153 – This is all true, how does this relate to guinea pigs though? Are we suggesting that their lifespan hasn’t improved as much as might be observed for other species? Why might this be?
I just am a but unsure about the variables that have been selected for analysis here and also how much this study differs from the O’Neill (2024) study that is based on the same dataset.
Line 107 – as far as I am aware there are no recognised brachycephalic breeds of guinea pig unlike rabbits – could you confirm why these categories were included as a predictor? Similarly, I don’t think giant breeds of guinea pigs exist.
Line 109 – I have not come across ‘Silky’ guinea pigs. I think from a quick search it might exist spelled ‘Silkie’ – I have only come across Satin and Sheltie breeds (might be a different name for Sheltie?).
Line 170 onwards (this is maybe more interpretation of the findings than validity) – while everything that you have written about female guinea pigs and pregnancy is valid, I am not sure this would be the main explanation for females surviving less time than predicted given the vast majority of pet owners are not breeding their pets. Obviously breeders would be, but they would be knowledgeable enough to know that sows need to have their first litter prior to the fusion of their pelvic symphysis. I understand there may be some accidental pregnancies among pet owners especially if younger animals have been incorrectly sexed, but given this would be more common for younger, more recently acquired animals, I don’t think this likely explains the results either. I am not sure what the explanation is – female guinea pigs have a very high prevalence of ovarian cysts when they are over a few years old (Sadar et al., 2025). This is now such a well-recognised problem that some exotic specialist vets are starting to move towards recommendation of routine spaying to prevent the issue. If the guinea pigs have surgery when older to remove cysts then this becomes riskier and your content about the risk of anaesthesia becomes highly relevant.
Line 185 – I agree, how many animals (n=) were neutered/spayed? This might be good to present descriptively in the results section in the text along with the percentage (which you include in the discussion). I know this is in the table but it is a key aspect that I think would be better in the text.
Thank you for the opportunity to read this manuscript that focuses on lifespan in guinea pigs. I commend research further investigating this species and these variables as I agree that estimates of lifespan from the literature are likely inaccurate. In terms of the variables investigated – breed, neuter status etc. I don’t think that these are as easy to examine/relevant for guinea pigs as other species as you have identified in your discussion. Guinea pigs are currently not that routinely neutered (although this might increase in future). Also, while lots of breeds exist, I think in the UK most pet owners just have mixed breed guinea pigs as these are what are sold in mainstream pet shops and there isn’t as much reason to have a specific breed as there might be for dogs/cats/rabbits as size etc. doesn’t vary much nor does temperament. The only real difference that might affect their care is the coat length and upkeep associated with this. I believe mostly breeders and people who show guinea pigs own purebreds and the majority of ‘normal’ owners do not. Furthermore, there are not really that many breed-specific health issues in guinea pigs that might affect lifespan in the same way as animals like cats/dogs/rabbits for which brachycephaly exists. I am only aware of satin syndrome and a few other rare abnormalities associated with specific breeds. Therefore, I am not that surprised regarding the findings – I wonder if other variables would have been more interesting to look at in terms of effect on survival – e.g. no. of presentations to the vet, specific health conditions suffered from etc. As I feel the current analysis doesn’t really result in much in the way of recommendations for changes of husbandry, care practices for owners to improve welfare.
The study aimed to investigate the survivability of British pet guinea pigs. The writing is concise and easy to follow. The topic of the manuscript is appropriate for the journal.
Figures are relevant. Raw data is available.
Abstract
Line 16-18: This is interesting but not relevant information.
Line 27-28: 4.022 (95% confidence interval 3.875, 4.170) years
Line 28: and an interquartile range of
Limitations of the study should also be mentioned in the abstract.
Introduction:
Line 38-68: In my opinion, the guinea pig domestication history is irrelevant. It would be more important to mention the most common life shortening diseases of guinea pigs or husbandry related health issues. Also, the potential life span of guinea pigs would be necessary.
Line 75-79: Factors such as sex, breed or neutering status have been identified, individually or together, as affecting survivability in domestic species such as dogs (Mata & Mata, 2023), cats (Mata, 2025b), pet rabbits (Mata, 2025a), cattle (Kirkpatrick, 2017), sheep (Málková· et al., 2020), chicken (Mata & Mwakifuna, 2012), Japanese quail (Khan et al., 2010).
How do these parameters influence survivability?
Please give a short introduction to the VetCompass Program.
Results
Line 122: The Kaplan-Meier tests applied to the factors sex, neutering status, and breed were found not significant (p > 0.05). Therefore, different lifespans were not found between the groups…
O’Neill et al. (2024 found: There were 757 deaths recorded among the 3,785 (20.00%) guinea pigs. Information on the age at death was available for 674/757 (89.04%) of deaths. The median age at death overall was 4.03 years (IQR 2.56–5.44, range 0.17–10.00). The median age at death in females (4.58 years, IQR 3.00–5.81, range 0.25–8.25) was statistically older than males (3.74, IQR 2.51–5.00, 0.17–10.00) (P < 0.001).
How can you explain the different results concerning the effect of sex on lifespan?
Please explain Table 4 in the text.
Table 1. Minimum, mean, median, 95% confidence intervals, interquartile range, and maximum lifespan of the sampled British pet guinea pigs in the present study.
+ Data are provided in years.
Table 4:
Please explain the abbreviations.
Interval time (year)
No exposed to risk. What do you mean by risk?
What do you mean by “hazard rate”?
Discussion
Line 164: No significant differences were found in the survivability of male and female pet guinea pigs. This differs from patterns seen in other species, especially mammals, where females are typically associated with greater longevity.
As shown in this and other studies, the neutering rate is low in female guinea pigs. Ovarian cysts are very common in guinea pigs, and it may shorten females’ lives. So, females do not necessarily have a longer lifespan.
Line 172: Pet guinea pig owners may want to wait longer before allowing reproduction.
How commonly have female pet guinea pigs offsprings? I assume most guinea pig owners do not want to breed their pets. This could explain why the neutering rate is higher in males. You wrote: „Additionally, when housing arrangements involve a single male living with multiple females, neutering the male rather than spaying all the females is the more practical option.”
Line 191: The low neutering rate in guinea pigs may be linked to concerns over anaesthetic risks referred to before.
Do you mean that the owners are aware of these potential risks, and thus, they are not willing to neuter their pets? Or do veterinarians not support neutering because of the risks? How did you measure this? The manuscript does not contain any details about it, so please add references.
Line 227: Additionally, the dataset does not account for potential environmental and husbandry-related factors, such as diet, housing conditions, and owner experience, which may play a role in individual longevity.
Nutrition has a huge impact on the health of guinea pigs. Diseases caused by poor nutrition (e.g., gastrointestinal and dental diseases) are very common and potentially life-threatening conditions in pet guinea pigs. This should be emphasized. In my opinion, nutrition (and other husbandry-related problems) has a much larger impact on longevity than sex or breed.
Conclusions:
Line 245: The study also highlights the low neutering rates in pet guinea pigs, likely due to the higher anaesthetic risks associated with these procedures.
The impact on anaesthesia was not measured in this study, so please add citations. Also, maybe owners are not aware of the health risks of ovarian cysts. See line 191.
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