Further Than Fur: Effects of Sex, Body Site, and Season on Hair Color and Hair Cortisol Concentration in Captive Addax nasomaculatus Antelopes

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study is interesting and shows the differences in hair cortisol and hair color in antelopes during the year.

 

The scientific name of the species is in italics. Check along the paper.

 

In the Introduction, a conexion between the first and second paragraphs is missing.

Line 117: Figure 2A and 2B should be part of the methodology, not the results, as you do not control the ambient conditions. Alternatively, you can exclude the citation here, as you wanted to show them in reference to hair cortisol.

 

Line 126-127: explain your sample size immediately after the population info in line 119.

Figure 2C: first Autumn must be deleted

Were females pregnant? Cycling in any season?

During each season, samples were taken? At the end?

Line 243-254: as some differences are present between sexes in different studies, could you check them for reproductive status? In citations and in your study? This factor could explain the sex variation between all cited studies.

Even in homosexual groups,animals develop a hierarchy atatus, which can be a factor for hair colour.

The species has an African origin,but the study was conducted in a subtropical climate, with 8-9years old antilopes. Were they born and raised in Uruguay? Could this alter hair colour in a different way if the animals were in Africa?

Do you know in which generation do the animals belong? Where has it adapted to the environment?

Author Response

(R) Reviewer 1

Comments and Suggestions for Authors

The study is interesting and shows the differences in hair cortisol and hair color in antelopes during the year.

• Authors: We thank the reviewer for the positive comments and for considering the study interesting.

 

R: The scientific name of the species is in italics. Check along the paper.

A: Thank you very much for the observation and apologies for the error. Throughout the manuscript we have italicized the name of the species, whether when it appears as “Addax nasomaculatus”.

 

R: In the Introduction, a conexion between the first and second paragraphs is missing.

A: We agree with the reviewer, thanks for the comment. We include the following: “According to Broom [3], ‘‘The welfare of an individual is its state as regards its attempts to cope with its environment.’’ Therefore, animals that best adapt to their environment show better welfare conditions. Among the tools to objectively evaluate how animals adapt to their environment, those linked to the stress response play an important role.” L50-54.

 

R: Line 117: Figure 2A and 2B should be part of the methodology, not the results, as you do not control the ambient conditions. Alternatively, you can exclude the citation here, as you wanted to show them in reference to hair cortisol.

A: Based on the reviewer's suggestion, we removed the following statement: “Changes in temperature (minimum, average and maximum) as well as changes in THI throughout seasons of the year are shown in Figure 2A and 2B.”. This is because, as the reviewer comments, we want to show variations in cortisol in relation to environmental changes.

 

R: Line 126-127: explain your sample size immediately after the population info in line 119.

A: As the reviewer suggested, we explained the sample size in the indicated place. Thus, following sentence was moved: “For this study, 1 adult female group (n=15; age= 8.8±3.8, mean±SD) and 5 adult male groups (N= 11; age=9.2±4.2, mean±SD) were used.” to L120-122.

 

R: Figure 2C: first Autumn must be deleted

A: We modified the figure as suggested by the reviewer. In any case, as changes in hair cortisol reflect the changes of the last few months, we wanted prefer to leave the previous environmental changes before the first sample of hair cortisol.

 

R: Were females pregnant? Cycling in any season?

A: The reviewer made an interesting question. Females considered in the study were not pregnant, as they did not have parturitions during or following period of the study. Regarding whether they were cycling or not, we do not know for sure, as there is very little information about it concerning the species. However, according to historical records, births occur in all seasons, although as was mentioned in our previous study (Villagrán et al.; 2023), in this populatuion "the females’ estrus cycles (i.e., the rut) may have occurred more frequently between the end of the spring and the summer.”

 

R: During each season, samples were taken? At the end?

A: Hair samples were obtained at the end of each season.

 

R: Line 243-254: as some differences are present between sexes in different studies, could you check them for reproductive status? In citations and in your study? This factor could explain the sex variation between all cited studies.

Even in homosexual groups,animals develop a hierarchy atatus, which can be a factor for hair colour.

A: We check reproductive status of the animals that were cited in the works in that paragraph. Some studies evaluated reproductive status, as mentioned below:

• Medill et al., 2023: They evaluated reproductive status as: “Female reproductive status is determinated by the presence or absence of a foal during the summer survey or a yearling present in the subsequent yerar´s survey (i.e., parturrition ocurred after the previous survey ended).”. They found that: “Females with a foal tended to have higher hair cortisol levels than females without a foal. The presence or absence of a nursing foal was related to a significant difference in HCC. A significant interaction between age and the presence or absence of a foal was also observed.
• Azevedo et al., 2019: They evaluated reproductive status as: “Each specimen was assigned as male or female based on the presence of testicles or ovaries, and the reproductive state of females was noted as pregnant (foetuses identified in the uterus), lactating (milk present in mammary glands) or non-breeding”. These authors did not found effect of reproductive state: “There was no evidence of an effect of reproductive state on hair cortisol in female mongoose”.
• Garber et al., 2020: These authors evaluated reproductive status as: “Adult females were classified as either pregnant/lactating or nonpregnant/nonlactating at the time of capture.”, and they reported that: “Female reproductive condition did not significantly affect HCC”.
• Dulude-de et al., 2019: They evaluated reproductive status as: “reproductive status (lactating/non-lactating)”, but, int thier result they reported the following: “Reproductive status of females did not appear to influence FGM or HCC”.

While the rest of the studies did not evaluate reproductive status:

Santangeli et al., 2019; Lafferty et al., 2015; Zenth et al., 2022; Lutz et al., 2021; Lavergne et al., 2020; Bergamin et al., 2019; Bechshøft et al., 2011; Fourie et al., 2016; Terwissen et al., 2013.

 

Based on this review, and the reviewer's suggestion, we included the following sentences in that paragraph:  “Another factor to consider that may also help explain the differences between different studies and species in the effect of sex and hair cortisol concentrations is the reproductive status of the animals. For example, Medill et al. [41] found that females possessing an offspring had higher levels of hair cortisol than those without one. Besides, other studies evaluated the reproductive status of females (i.e pregnancy or lactating condition) and the moment in relation to the reproductive season. However, these studies found no effect of reproductive status on hair cortisol concentrations [42, 47, 48]. The other studies did not evaluate reproductive status on hair cortisol concentrations [27, 29-30, 43-46, 49, 50]. Although females were not pregnant in our study, when compared to males, we exclude the possible effect of females cycling on hair cortisol concentrations. Furthermore, within the same sexual group, social factors such as hierarchy could influence hair variables.” L256-267.

 

R: The species has an African origin,but the study was conducted in a subtropical climate, with 8-9years old antilopes. Were they born and raised in Uruguay? Could this alter hair colour in a different way if the animals were in Africa?

A: We really thank reviewer comment. These animals were born in this population, in Uruguay, which was founded more than 30 years ago. Regarding the second question, we believe that color changes do not significantly between animals from Uruguay and those from Africa. Actually, a specially shorter and whiter hair were reported in summer in addax in Africa (Krausman and Casey, 2007), which are similar to our results. Beyond this, it would be interesting to objectively measure hair color (as we did in this study) with animals living in Africa. Very good idea to work on in the future.

 

R: Do you know in which generation do the animals belong? Where has it adapted to the environment?

A: As was mentioned before, this breeding in this population stared around 30 years ago, so there were several generations. However, unfortunately we do not have information on the specific generation to which each individual corresponds..

With respect to adaptation, given that the environmental pressures of being bred in captivity in Uruguay have been different from those of Africa in the wild, it would be interesting to evaluate these topics in the wild.

The authors would like to thank the reviewer for the careful review, and for helping to improve the manuscript.

 

 

 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Line 107: were animals previously shaved so that the hair sample first collected in October 2021 was only from the previous season? Or does this species undergo a full molt prior so that the hair shaved in Oct was only grown during the previous season? And like-wise for subsequent samples collected.

paragraph starting on Line 307: I think the potential role sun-bleaching has on coat color during the different seasons (particularly the increase in white following summer and spring) should be considered and addressed here.

Comments on the Quality of English Language

Line 14: italicize Addax nasomaculatus  and throughout paper

Line 17: “in zoo-housed addax”

Line 33: “these differences being more significant in the spring”

Line 43: italicize Addax nasomaculatus

Line 51-2: “induced by stimuli, noxious or events known” – awkward wording

Line 59: “has been proven” àhas been shown

Line 66: “body site, colour hair” à “body site, hair colour”

Line 95 “Based on this observation”

Line 101: italicize Addax nasomaculatus

Line 118-9: “composed of adult females (n=?), adult males (n=?), yearlings (n=?) and fawns (age <1year old, n=?).

Line 122: “Paddlocks” à “Paddocks”

Line 123: “crush” à “squeeze” is the more common word used in English

Line 126-7: mean ages? Please include range or SD/SEM as well

Line 130: Did you shave the exact same patch each time, or different patches within the target region?

Line 132: “crush” à “squeeze”

Line 139: italicize Addax nasomaculatus

Line 107: were animals previously shaved so that the hair sample first collected in October 2021 was only from the previous season? Or does this species undergo a full molt prior so that the hair shaved in Oct was only grown during the previous season?

Line 207: could you please include what those parameters mean in the description or legend? (L* = lightness, 10=black, 100=white, etc)

Line 210: is it possible this seasonal difference is due to sun-bleaching of the coat? Or do these animals shed seasonally?

Line 255: “across seasons of differed” à “across seasons differed”

Line 261: “conditions occurred two-three months” à “conditions experienced two-three”

Line 262: “conditions experienced”

Line 280: “raised in Uruguay for more longer than” à “raised in Uruguay for more than”

Line 281: italicize genus and species

Line 269: “in summer, both temperature and THI increase”

Line 311: “housed in same-sex groups”

PPG starting on Line 307: I think the potential role sun-bleaching has on coat color during the different seasons (particularly the increase in white following summer and spring) should be considered and addressed here.

Author Response

(R) Reviewer 2

Comments and Suggestions for Authors

Line 107: were animals previously shaved so that the hair sample first collected in October 2021 was only from the previous season? Or does this species undergo a full molt prior so that the hair shaved in Oct was only grown during the previous season? And like-wise for subsequent samples collected.

• Authors: Thank you to the reviewer for taking the time to review and help improving this manuscript. Regarding your questions, before obtaining the first sample at the first season the animals were not previously shaved. In the other seasons, since the samples were obtained at the end of each season, it allowed to obtain hair that had grown during each particular season.

R: paragraph starting on Line 307: I think the potential role sun-bleaching has on coat color during the different seasons (particularly the increase in white following summer and spring) should be considered and addressed here.

A: We agree with the suggestion, and therefore we incorporated the following sentence at the end of the discussion: “Furthermore, it is important to consider the potential role of sun-bleaching on coat colour during the different seasons, particularly the increase in white following summer and spring. Although the experimental design of this study does not allow inferences in this regard, it is important to take into account the possible role of sun exposure on hair colour.” L341-345.

 

R: Comments on the Quality of English Language

Line 14: italicize Addax nasomaculatus  and throughout paper

A: Thank you very much for the observation and apologies for the error. Throughout the manuscript we have italicized the name of the species, whether when it appears as “Addax nasomaculatus”.

R: Line 17: “in zoo-housed addax”

A: Thank you, we made the change.

 

R: Line 33: “these differences being more significant in the spring”

A: The suggestion was done.

 

R: Line 43: italicize Addax nasomaculatus

A: The change was done.

 

R: Line 51-2: “induced by stimuli, noxious or events known” – awkward wording

A: Thank you for signaling this. We modified the original sentence as “induced by a stimuli or noxious event, frequently defined as “stressor”. L54-55.

 

R: Line 59: “has been proven” àhas been shown

A: The change was done.

 

R: Line 66: “body site, colour hair” à “body site, hair colour”

A: The change was done.

 

R: Line 95 “Based on this observation”

A: The change was done.

 

R: Line 101: italicize Addax nasomaculatus

A: The change was done.

 

R: Line 118-9: “composed of adult females (n=?), adult males (n=?), yearlings (n=?) and fawns (age <1year old, n=?).

A: According to comments also made by the other reviewer, we unified both comments, and we rewrite the sentence as follows: “At the beginning of the study, the addax population had 36 individuals, composed of adult females, adult males, yearlings and fawns (age<1 year old)]. For this study, 1 adult female group (n=15; age= 8.8±3.8, mean±SD) and 5 adult male groups (N= 11; age=9.2±4.2, mean±SD) were used” L120-122.

 

R: Line 122: “Paddlocks” à “Paddocks”

A: The change was done.

 

1. Line 123: “crush” à “squeeze” is the more common word used in English

A: Thank you for the suggestions to improve English writing. The change was done.

 

R: Line 126-7: mean ages? Please include range or SD/SEM as well

A:  We included the following: “For this study, 1 adult female group (n= 15; age= 8.8±3.8, mean±SD) and 5 adult male groups (N= 11; age= 9.2±4.2, mean±SD) were used.” L120-122.

 

R: Line 130: Did you shave the exact same patch each time, or different patches within the target region?

A: We always shave the exact same patch each time.

 

R: Line 132: “crush” à “squeeze”

A: The change was done.

 

R: Line 139: italicize Addax nasomaculatus

A: The change was done.

 

R: Line 107: were animals previously shaved so that the hair sample first collected in October 2021 was only from the previous season? Or does this species undergo a full molt prior so that the hair shaved in Oct was only grown during the previous season?

A: As was early mentionated, animals were not previously shaved before obtaining the first sample at the first station. In the other seasons, since the samples were obtained at the end of each season, the time period of hair growth allowed us to follow them for each particular season.

 

R: Line 207: could you please include what those parameters mean in the description or legend? (L* = lightness, 10=black, 100=white, etc)

A: We include the following at the bottom of Table 1: “Lightness (L*): from 10= blackness to 100= whiteness; Yellowness (b*): from blue (nega-tive value) to yellow (positive value), Redness (a*): from green (negative value) to red (positive value).” L211-212.

 

R: Line 210: is it possible this seasonal difference is due to sun-bleaching of the coat? Or do these animals shed seasonally?

A: We cannot discard any of both phenomenon as part of the explanation, since the experimental design doesn't allow us to infer on that topic. We agree with the suggestion, and therefore we incorporated the following at the end of the discussion: “Furthermore, it is important to consider the potential role that different sun-bleaching could has on coat colour between the seasons, particularly concerning the increase in white color hair following summer and spring. Although the experimental design of this study does not allow inferring in this regard, it is important to take into account the possible role of sun exposure on hair colour.” L341-345.

 

R: Line 255: “across seasons of differed” à “across seasons differed”

A: The change was done. Thank you.

 

R: Line 261: “conditions occurred two-three months” à “conditions experienced two-three”

A: The change was done.

 

R: Line 262: “conditions experienced”

A: The change was done.

 

R: Line 280: “raised in Uruguay for more longer than” à “raised in Uruguay for more than”

A: The change was done.

 

Line 281: italicize genus and species

A: Thank you, the changes were done.

 

R: Line 269: “in summer, both temperature and THI increase”

A: The change was done.

 

R: Line 311: “housed in same-sex groups”

A: The change was done.

 

 

R: PPG starting on Line 307: I think the potential role sun-bleaching has on coat color during the different seasons (particularly the increase in white following summer and spring) should be considered and addressed here.

A: Thanks to the reviewer for the suggestion. We agree with the suggestion, and therefore we incorporated the following at the end of the discussion: “Furthermore, it is important to consider the potential role of sun-bleaching on coat colour during the different seasons, particularly the increase in white following sum-mer and spring. Although the experimental design of this study does not allow infer-ences in this regard, it is important to take into account the possible role of sun expo-sure on hair colour.” L341-345.

Author Response File: Author Response.docx