RETRACTED ARTICLE: Factors affecting Nile crocodile (Crocodylus niloticus) leather quality: a systematic review

TL;DR

This paper reviews factors affecting the quality of Nile crocodile leather, including genetics, environment, and farming practices.

Contribution

The study systematically integrates current research to provide actionable recommendations for improving Nile crocodile leather quality.

Findings

Genetic diversity and selective breeding improve skin quality and disease resistance in Nile crocodiles.

Environmental factors like water quality and temperature significantly affect skin health.

Farming practices such as stocking density and diet influence leather quality by reducing stress and infections.

Abstract

Leather from the Nile crocodile (Crocodylus niloticus) is highly valued in global markets due to its durability, distinct texture, and aesthetic appeal. Despite its economic importance, the crocodile industry faces substantial challenges in maintaining the leather quality due to a variety of influencing factors. This study systematically reviews the literature that investigated the genetic, environmental, and management factors that influence the leather quality of Nile crocodiles. A comprehensive search on Google Scholar, ResearchGate, PubMed, and ScienceDirect databases yielded twenty-four studies published between 1960 and 2023. The analysis shows that genetic diversity and selective breeding programs play an important role in improving skin quality by promoting desirable traits and disease resistance. Environmental factors such as water quality, temperature, and habitat conditions have a substantial impact on skin health, with poor water quality and extreme temperatures contributing to skin diseases and defects. Management practices in crocodile farms should emphasize ideal stocking densities, balanced diets, and regular health screenings, which are essential for minimizing stress, injuries, and infections that degrade leather quality. Comparative studies with other crocodilian species, such as saltwater crocodiles, caimans, and American alligators, revealed both similarities and differences in the factors that influence leather quality, providing useful insights for improving techniques across species. This review adds to the body of knowledge by integrating current studies and providing actionable recommendations for improving Nile crocodile leather quality through improved genetic, environmental, and management practices. Scarcity of studies on crocodile leather remain a challenge. However, future research are needed that will explore longitudinal studies and the establishment of advanced practices to promote sustainable crocodile farming and assure the improved leather quality and industry's profitability.

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Introduction

The Nile crocodile (Crocodylus niloticus) is widely distributed across Sub-Saharan Africa, thriving in freshwater habitats such as rivers, lakes, and marshlands. They are recognized as one of the largest crocodilian species in Sub-Saharan Africa, and are one of the biggest crocodile species native to the continent (Modha 1967). Beyond its role as an apex predator, the Nile crocodile is highly prized for its exceptionally durable and luxurious leather, which commands significant value in the global market. Each year, thousands are either harvested from the wild or bred in controlled environments, contributing substantially to the economies of nations such as South Africa, Zambia, and Zimbabwe (Hutton 1987). However, the implementation of sustainable management practices remains imperative to safeguard both wild populations and the long-term viability of the industry.

Crocodile leather is an exotic leather. Naher et al. (2015) described exotic leather as a distinctively unique leather produced from skins or hides of rare animals or waste parts of domesticated animals. Exotic leathers are preferred due to their appearance, natural occurring marks, patterns and structure, with the demand for its use markedly increasing in the leather market (Alla et al. 2017). Leather from Nile crocodiles (Crocodylus niloticus), is in high demand worldwide due to its resilience, distinct texture, and aesthetic appeal (Fuchs 2006; Chala et al. 2020; Webb et al. 2021). Crocodile leather is rare, expensive and used for making handbags, shoes, belts, wallets, upholstery, and furniture (Maina et al. 2019; Chala et al. 2020). Currently, crocodile leather contributes 1% to the world's leather production (Chala et al. 2020). Countries such as South Africa, Zambia, and Zimbabwe have made considerable contributions to this industry, with South Africa ranking among the top exporters (Hutton 1987). In 2021, the exports of Nile crocodile leather raked in around $105 million, indicating its economic importance (Webb et al. 2021). Despite its lucrative nature, the industry faces difficulties in maintaining the quality of crocodile skins, which are frequently downgraded owing to a variety of factors. High-quality leather is critical not only for economic value, but also for maintaining export competitiveness. Inferior skin quality cannot only reduce the leather's market value, however, it will have a negative impact on the overall sustainability of crocodile farming operations, while skin downgrading significantly affects the profitability and sustainability of the crocodile industry (Fuchs 2006).

Huchzermeyer (2003) emphasized on the impact of the genetic factors, environmental conditions, and management practices on the quality of Nile crocodile leather. Hence, Hilevski et al. (2023) stated that genetic and environmental factors are important in determining skin quality in saltwater crocodiles. On genetic base, Fuchs (2006) and Webb et al. (2020a, b) mentioned that factors such as genetic variety and selective breeding programs are critical for improving traits resulting in smoother and more resilient skins. Environmental factors such as water quality and temperature plays a critical role on the skin health of Nile crocodiles (Webb et al. 2021). Hilevski et al. (2020) reported that poor water quality could cause skin infections and illnesses, which significantly reduces leather quality. Furthermore, temperature regulation is critical, since excessive temperatures can stress crocodiles, resulting in skin flaws and defects (Fuchs et al. 2019).

Skin quality is known to be influenced by factors such as stocking density, diet, and health management. Research has shown that stocking density has a substantial impact on Nile crocodile growth and skin quality (Webb et al. 2021). Crocodiles under high stocking densities are more likely to exhibit aggression and injuries, resulting in lower skin quality (Webb et al. 2021). Another study examines the relationship between skin disorders and leather quality in captive crocodilians, emphasizing the importance of proper health management practices (Hilevski et al. 2023). The diet and nutrition are also crucial management practices and have a direct impact on crocodiles' overall health and skin condition. A well-balanced diet high in essential nutrients promotes healthy skin growth, but nutritional deficiencies can cause a variety of skin disorders that reduce leather quality (Hilevski et al. 2021).

This systematic review intends to add to the knowledge body on the factors that influence the leather quality of Nile crocodiles. Limited research has been done on other crocodilian species such as saltwater crocodiles (Crocodylus porosus), caimans (Caiman spp.), and American alligators (Alligator mississippiensis), sharing similar habitats and farming conditions with the Nile crocodiles. Including these species in the review will assist to provide knowledge that is more comprehensive and identify common factors influencing skin quality across species. Addressing these will provide actionable insights for enhancing Nile crocodile leather quality. It will also emphasizes the importance of improving management practices and encourage profitable and sustainable crocodile farming.

Methods and materials

Eligibility criteria

Due to limited information on Nile crocodiles, the study population included the Nile crocodile (Crocodylus niloticus), along with other comparable exotic species such as the saltwater crocodile (Crocodylus porosus), caiman (Caiman spp.), and American alligator (Alligator mississippiensis). The interventions of the study are the numerous genetic factors, environmental conditions and management practices on leather quality, also in which comparisons will be made based on such. The outcome being the quality of crocodile leather is determined by attributes such as durability, flexibility, strength, texture and appearance, which are preliminary searched on the databases Google Scholar, ResearchGate, ScienceDirect and PubMed prior to the research study.

Search strategy

The search strategy for this study identified relevant studies that focused on the factors affecting Nile crocodile leather quality. The search was conducted using the databases Google Scholar and ResearchGate, ScienceDirect and PubMed. A combination of specific keywords, inclusion and exclusion criteria, and structured approaches were employed to ensure comprehensive and unbiased coverage of the topic. The search terms that were used but not limited to, included the following: "Nile crocodile leather quality," "Crocodylus niloticus leather," "genetic factors on crocodile leather," "environmental impact crocodile skin," "management practices crocodile farming," "alligator leather quality," "caiman leather quality," "crocodile skin health," "leather texture durability crocodile," "farming methods crocodile leather," or "handling techniques crocodile skin." To refine the search results, a comprehensive search string was created with these keywords and Boolean operators. The following exemplary search string was considered: ("Nile crocodile" or "Crocodylus niloticus" or "alligator" or "caiman") and ("leather quality" or "skin health" or "leather texture" or "leather durability") and ("genetic factors" or "environmental conditions" or "management practices" or "farming methods" or "handling techniques").

Inclusion Criteria

The inclusion criteria of the study were: (1) articles written in English (2) studies published between 1960 and 2023 due to limited studies (3) research focusing on Nile crocodiles (Crocodylus niloticus), saltwater crocodiles (Crocodylus porosus), caimans (Caiman spp.) and American alligators (Alligator mississippiensis), and other exotic leather species in relation to leather quality (4) research on exotic skins (5) empirical studies on factors influencing crocodile leather quality.

Exclusion criteria

The exclusion criteria of the study were: (1) articles not published in English (2) studies published prior to 1960 and after 2023 (3), research not focusing on Nile crocodiles, saltwater crocodiles, caimans and American alligators (4) research not focusing on exotic skins (5) non-empirical studies, review articles, opinion pieces, or studies based on anecdotes and personal bias.

Data extraction

Data extraction for the study was performed by Ndzalo Khosa and Khetho Ratshilumela Nemutandani, who systematically reviewed and agreed upon the relevant materials. The extracted information from the included articles covered the following key areas: Author(s), Year of Publication, Study Design, Population (Nile crocodiles, alligators and caimans and saltwater crocodiles), Intervention (genetic factors, environmental conditions, and management practices), Comparison, and Outcomes (focusing on measures of leather quality such as texture, strength, and durability). The titles and abstracts of the retrieved articles were screened to identify potentially relevant studies, excluding those that did not meet the eligibility criteria. The entire text of publications that pass the initial screening were obtained and checked to ensure that the inclusion criteria matches. Additionally, a manual search of the reference lists of included studies was done to find any other relevant papers that may not have been captured in the initial search. The search procedure was thoroughly documented; including the keywords used, search strings, number of publications found, and inclusion/exclusion criteria.

Results

Literature searched results

The Fig. 1 above shows a PRISMA flowchart of the research and the selection procedure for the systematic review at various stages. Academic search engines including Google Scholar, ResearchGate, ScienceDirect, and PubMed retrieved 52 articles. The retrieval and selection procedures are summarized below: 52 studies were initially retrieved. Duplicate removal: 15.4% (8/52) of the records were found to be duplicates. Title Screening: 23.1% (12/52) were deleted due to not meeting the inclusion requirements. Abstract Screening: 15.4% (8/52) were removed owing to a lack of relevance to the topic. Eligibility Screening: During the eligibility screening stage no articles were excluded due to not meeting the full-text inclusion standards. As a result, 46.2% (24/52) of the collected documents were included in the systematic review.Fig. 1PRISMA flowchart

Characteristics of included studies

The included studies describe the characteristics of the twenty-four (n = 24) studies that were considered appropriate for inclusion in this systematic review. Only four of these studies (n = 4) were conducted by a single author. Webb, Hilevski, and Fergusson were authors in several studies, with Webb appearing in four (n = 4), Hilevski in three (n = 3), and Fergusson in two (n = 2) studies. Overall, the studies focused on four crocodilian species: Nile crocodiles (Crocodylus niloticus), saltwater crocodiles (Crocodylus porosus), caimans (Caiman spp.), and American alligators (Alligator mississippiensis), as well as other exotic leathers. The studies examined various factors influencing leather quality, namely genetic factors, environmental conditions, and management practices. In total, seven studies focused on genetic factors influencing leather quality, eight studies on environmental conditions affecting leather quality, and nine studies on management practices influencing leather quality were examined. This systematic review shows that Nile crocodiles (Crocodylus niloticus) were investigated in 11 studies, saltwater crocodiles (Crocodylus porosus) in 3 studies, caimans (Caiman spp.) in 4 studies, American alligators (Alligator mississippiensis) in 3 studies, and other exotic skins in 3 studies. The age groups and sexes included adults were studied in twelve studies, juveniles in five studies, and both sexes in eight studies. The study settings included captive habitats in 12 studies and natural habitats in 8 studies.

Origin of publications

Figures 2 and 3 shows the origin of the studies used in this systematic review. The studies were from twelve different countries (Figs. 2 and 3). The findings revealed that the majority of the studies (n = 6) originated from South Africa. Zambia and Zimbabwe each had three studies (n = 3). The United States of America, Bangladesh and Kenya supplied two studies (n = 2) each, whereas Argentina (Hilevski et al. 2023), the United Kingdom (Huchzermeyer 2003), Australia (Manolis and Webb 2005), India, Ethiopia and Germany contributed one study (n = 1) each.Fig. 2. Origin of publicationsFig. 3Origin of publications: Continent map

Year of publications

Figure 4 shows the years of publication for the included studies. The results showed that the studies' publication years ranged from 1960 to 2023 (Fig. 4). It was also noticed that a large number of studies (n = 20) were published between 2000 and 2023. The second most popular publication year range was 1980–1989, with two (n = 2) studies. Between 1960 and 1979, only two studies were published

Year of publications

Publications by journal

The studies included in the systematic review are shown in Table 1. Out of the twenty-four (n = 24) studies, twenty (n = 20) were published across sixteen (n = 16) different journals. The other four (n = 4) studies were published as books and reports. The review also found that 25% (4 out of 16) of the journals appeared in two separate papers, while the other twelve (n = 12) journals only appeared in one article each. Table 1. Publications by journalJournal NameNumber of studiesReferencesSouth African Journal of Animal Science1Webb et al. 2021ScienceDirect2Veldsman et al. 2021; Hilevski et al. 2020Herpetology Notes1Hilevski et al. 2023Wildlife Research1Manolis and Webb 2005East African Wildlife Journal1Modha 1967PubMed3Fuchs et al. 2019; Webb et al. 2020a; Fuchs 2006Google Scholar2Swan et al. 2020;Myburgh et al. 2020ResearchGate2Webb et al. 2020b;Hilevski et al. 2021Facts on File1Pooley 1989IUCN CSG1Ahmed 2013CABI Publishing1Huchzermeyer 2003Books2Huchzermeyer 2003; Ahmed 2013Reports2Hutton 1987; Huchzermeyer 2003Journal of the American Leather Chemists Association1Alla et al. 2017International Journal of Development Research1Chala et al. 2020International Journal of Scientific and Research Publications1Maina et al. 2019International Journal of Scientific & Technology Research1Naher et al. 2015

Distribution of genetic factors studies

Figure 5 shows the distribution of studies that focuses on genetic factors influencing Nile crocodile leather quality. The findings of this review shows that out of the twenty-four (n = 24) reviewed articles, seven (n = 7) studies that focused on genetic factors constituted 29%. These studies examined how genetic diversity, hereditary characteristics, and genetic improvement programmes affected the skin quality of Nile crocodiles. Genetic influences were investigated in studies by Huchzermeyer (2003), Fergusson (2010), Webb et al. (2020a, b), Fuchs et al. (2019), and others.Fig. 5. Distribution of genetic factors studies

Environmental conditions

Figure 6 shows the distribution of studies on environmental conditions. Eight of the twenty-four (n = 24) reviewed articles investigated how environmental variables such as water quality, temperature, and habitat affect the skin quality of Nile crocodiles, constituted 33% of the studies. Webb et al. (2021) and Hilevski et al. (2023) cited that these factors have a substantial influence on leather quality. Environmental conditions were the most commonly researched subtopic.Fig. 6. Distribution of the environmental conditions’ studies

Management practices

Figure 7 presents the distribution of studies that focuses on management practices. Nine of the twenty-four (n = 24) reviewed articles explored the impact of management practices on Nile crocodile leather quality, constituted 38% of the included studies. These studies investigated topics focused on stocking density, diet, and health-management techniques. Webb et al. (2021) and Ahmed (2013) have conducted important studies on this subtopic.Fig. 7. Distribution of management practices studies

Comparison with other crocodilian species

Figure 8 shows a comparison of factors affecting leather quality across various crocodilian species. Of the twenty-four (n = 24) reviewed articles, eight (n = 8) studies focused on comparisons between Nile crocodiles and other species such as saltwater crocodiles (Crocodylus porosus), caimans (Caiman spp.), and American alligators (Alligator mississippiensis), constituted 33% of the studies. These comparative studies provide valuable insights into the similarities and differences in genetic, environmental, and management factors influencing leather quality across different species, which can inform practices for improving Nile crocodile leather quality.Fig. 8. Distribution of comparison with other crocodilian species studies

Discussion

This study was conducted with an objective to systematically review the literature that investigated the factors that influence the leather quality of Nile crocodiles (Crocodylus niloticus), with the focus on genetic, environmental conditions, and management practices. This review combined findings from twenty four studies, offering a full understanding of how these factors influence leather quality and making recommendations for improving leather quality and ensuring sustainable crocodile farming. There are limited studies focusing on the quality of crocodile leather.

Genetic factors

Genetic factors affect various skin characteristics and it plays an important role in the quality of Nile crocodile leather. The genetic diversity within the populations has a significant impact on skin quality, as it influences a wider range of genetic traits that contribute to disease resistance, uniform skin texture, and optimal skin thickness, all of which are required to produce high-quality leather (Fuchs 2006). Genetic diversity has an influence on the quality of exotic leathers. Alla et al. (2017) described that exotic leather of reptile species such as crocodile skins, derives most of its value from its texture and durability, which are influenced by genetics. Hence, maintaining a diverse genetic pool helps to prevent inbreeding, which can cause a number health issues and poor skin quality (Modha 1967). Genetic disorders, such as albinism and scalesness, are more common in inbred populations and result in unmarketable leather. Fuchs (2006) cited that inbreeding, which reduces genetic variation, can increase the prevalence of genetic defects and skin problems such as uneven scaling, discoloration, and weaker skin structure, all of which would degrade leather quality by making the skin more susceptible to infections and physical damage. While a lack of genetic variation might create a homogeneous population that is more susceptible to disease outbreaks, resulting in lesions and other skin damage (Hilevski et al. 2023).

Selective breeding efforts may improve traits that lead to high-quality leather. Crocodiles with outstanding qualities are carefully selected and produced as part of genetic enhancement initiatives. These programs helps in the improvement of leather by ensuring uniform and fine scales, which are required for high-quality leather. Huchzermeyer (2003) emphasized the importance of genetic improvement programs in increasing leather quality through the selection of traits that result in smoother, more robust skins. This also involves recognizing and propagating desirable traits such as fine, homogeneous scales, resistance to skin disorders, and ideal skin thickness. Findings of this study aligned with Alla et al. (2017) who described that selective breeding programs can improve the quality of leather by fostering desired genetic traits like uniform scale patterns, which are particularly important for high-end luxury products. Genetic improvement also focuses on boosting disease resistance in the population, which lowers the prevalence of skin diseases that might reduce the attractiveness of leather (Huchzermeyer 2003).

Fuchs (2006) mentioned that molecular genetics techniques, such as marker-assisted selection, could aid in the optimization of breeding programs by identifying and selecting for specific genes associated with desirable traits (Fuchs 2006). By using modern genetic technologies such as Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and genome-wide association studies (GWAS), these can better identify and improve genetic traits associated with higher leather quality (Fuchs 2006). Although there is a general lack of scientific literature, further research needs to be done, as understanding these genetic influences is essential for sustainable crocodile farming and maximizing leather market value.

Environmental factors

Water quality, temperature, and ecosystem factors all influence skin health and quality (Webb et al. 2021). Poor water quality can result in skin diseases and illnesses such as dermatophilosis, fungal infections, and parasitic infections, all of which lower leather quality by causing lesions, scarring, and other skin defects (Hilevski et al. 2023). Contaminated water sources and poor habitat conditions often lead to bacterial infections and skin disorders, negatively affecting the quality of the finished leather. Maina et al. (2019) stated that managing environmental conditions in crocodile farming can directly impact skin health, particularly in animals raised in captivity.

Temperature management is critical as high temperatures above 30 °C induce stress in crocodiles, leading to skin faults and deformities, while temperatures below 20 °C can cause cold stress, resulting in frostbite or thermal burns (Ahmed 2013). This finding is consistent with prior research on saltwater crocodiles(Crocodylus porosis) and caimans (Caiman spp.), in which appropriate water quality and temperature rendered crucial for skin health (Huchzermeyer 2003; Hilevski et al. 2023). Skin disorders such as dermatophilosis and fungal infections can be caused by poor water quality, which is defined by high pollution levels and an uneven pH**.** These disorders result in ulcers, scabs, and other skin anomalies, rendering the leather worthless. Webb et al. (2021) stated that crocodiles housed in contaminated water experience severe skin disorders such ulcers and necrotic tissue, resulting in inferior leather quality. Ahmed (2013) described that fluctuating temperatures may stress crocodiles, weakening their immune systems and making them more prone to sickness. Hence, maintaining stable and optimal temperature ranges supports healthy skin and overall well-being.

Habitat conditions, such as the presence of basking areas and appropriate shelter, are critical. Inadequate basking areas may cause insufficient thermoregulation, resulting in skin issues (Myburgh et al. 2020). Hilevski et al. (2023) described that crocodiles with limited access to basking sites showed uneven skin shedding, resulting in rough and patchy leather. Proper habitat management, which emulates the natural environment, can help ease these issues and promote healthy skin. Ensuring adequate space and proper basking areas reduces stress and minimizes overcrowding, which can lead to injuries and skin damage. Huchzermeyer (2003) reported that vitamin D synthesis requires appropriate ultraviolet (UV) light exposure, which is necessary for calcium metabolism and skin health. Inadequate UV exposure can cause vitamin D deficiency, resulting in weak bones and poor skin quality. Controlled UV lighting in captivity ensures that crocodiles receive enough exposure to maintain good skin development and overall health. Furthermore, Alla et al. (2017) stated that environmental and handling factors have a direct impact on the final quality of exotic leathers such as crocodile skin, emphasizing the importance of maintaining pristine environmental conditions to optimize leather outcomes.

Maintaining a balanced humidity level is critical for Nile crocodiles, because it prevents the skin from becoming too dry which may cause cracking, or being too moist, promoting a breeding ground for fungal infections. Maintaining appropriate temperatures is also vital, because extreme fluctuations can cause thermal burns or frostbite, compromising the integrity of the skin (Maina et al. 2019). By following these guidelines, crocodile farmers can reduce the impact of environmental harm to the skin, ensuring that the leather remains defect-free and preserves its value. This proactive approach could help prevent the onset of skin disorders, thus improving the overall quality of the leather produced.

Management practices

Management practices such as stocking density, diet, and health management influences the skin quality. High stocking densities causes overpopulation, increases the likelihood of hostile confrontations between crocodiles exhibiting increased aggression and injuries, resulting in poorer skin quality (Webb et al. 2021). These encounters frequently leave bite marks, scratches, and scars on the leather. Optimal stocking densities reduce stress and injury, leading to better skin quality (Veldsman et al. 2021). This finding is confirmed by research on other crocodilian species, which has shown that similar management practices affect leather quality (Huchzermeyer 2003; Fuchs 2006). In contrast, lower stocking densities reduce competition for resources and space, resulting in fewer hostile interactions and injuries. Maintaining the appropriate number of crocodiles per enclosure based on size and age can help reduce these interactions. Adequate space allows crocodiles to behave naturally and reduces the danger of skin damage during confrontations (Huchzermeyer 2003).

Nutrition is an important factor in the nourishment of the animal and their products. A balanced diet with high contents of nutrients such proteins, vitamins A and E, zinc, and omega-3 fatty acids is essential to promote healthy skin growth (Pooley 1989). Nutritional deficiencies can cause a variety of skin disorders, such as dermatitis, decreased skin suppleness, and slower wound healing, all of which affect leather quality. Ahmed (2013) mentioned that crocodiles fed a vitamin and mineral-deficient diet shows scaly skin, discolouration, and slower wound healing. Furthermore, the presence of pollutants in feed, such as heavy metals, may cause toxic reactions seen as skin lesions (Huchzermeyer 2003). The quality and composition of the diet, particularly the protein, fat, and vitamin ratio, are crucial for skin health and high-quality leather production.

Health management best practices, such as frequent check-ups and vaccinations, are essential for preventing diseases that damage skin quality. Diseases like crocodile pox and mycobacteriosis cause blisters and scabs, rendering leather useless. Regular health screenings can aid in the early detection and treatment of such issues, hence lowering their impact on skin quality (Ahmed 2013). Webb et al. (2021) cited that management practices, such as minimising handling techniques and ensuring a stable environment, are essential for maintaining healthy skin. Crocodiles require frequent veterinary treatment to ensure their wellbeing. Preventative measures, such as immunizations like the Crocodile Pox vaccine and the Salmonella vaccine, as well as appropriate parasite management, are critical in preventing infections that could impair skin health. These immunizations protect against common diseases that can cause skin lesions, ulcers, and scars, while frequent deworming and antiparasitic treatments help avoid parasite infestations like hookworms and mites, which can cause skin irritation and damage (Swan et al. 2020). Early detection and treatment of infections reduce their impact on leather quality, ensuring that crocodiles remain healthy and have flaw-free skin (Ahmed 2013). Health management measures are also essential for maintaining skin quality.

Alla et al. (2017) cited that optimal handling and processing techniques significantly enhance the value of exotic leathers such as fish skin and Nile crocodile leather. It is emphasized that careful skinning and timely preservation post-slaughter prevent damage could lower leather quality. Handling practices, such as gentle handling to avoid bruising or abrasions, are essential for maintaining high-quality exotic leathers (Alla et al. 2017). Moreover, the leather preparation process for exotic hides, especially those as sensitive as Nile crocodile skin, requires precise care at every stage to ensure that the leather retains its luxurious texture (Chala et al. 2020). Naher et al. (2015) mentioned how advancements in tanning processes, especially in the production of novelty leathers like those from cattle stomachs, have allowed for improvements in the overall quality and texture of exotic leathers. These tanning innovations can be applied to other exotic species like crocodiles to enhance the leather’s durability and finish, helping farmers and manufacturers meet consumer expectations for luxury products (Naher et al. 2015). Ensuring that these practices are followed consistently is essential for the sustainability and profitability of exotic leather production.

Comparison

This review also covers studies that investigates factors that determine leather quality in Nile crocodiles versus other crocodilian species such saltwater crocodiles, Caimans, and American alligators. The study of leather quality in different crocodilian species finds significant similarities in the environmental conditions and management practices required to create high-quality leather (Staton and Dixon 1977). Huchzermeyer (2003) found that American alligators, Caimans, and Nile crocodiles share genetic characteristics that influence leather quality. Nonetheless, each species had unique environmental adaptations that influenced their skin health and resilience. Hilevski et al. (2023) found that genetic diversity and hereditary characteristics had a substantial impact on the skin quality of saltwater crocodiles, similar to the findings for Nile crocodiles. Fuchs (2006) discovered that genetic factors influence skin quality in both American alligators and caimans, which are similar to Nile crocodiles, although there were differences in the health management practices implementation and their effectiveness across species. Environmental stressors such as water quality and temperature have varying effects, with saltwater crocodiles demonstrating greater resilience than Nile crocodiles. According to Webb et al. (2021), environmental conditions such as habitat and water quality have a similar effect on the leather quality of saltwater and Nile crocodiles. However, differences in nutritional requirements and feeding practices resulted in different skin quality outcomes. According to Hilevski et al. (2023), poor water quality in saltwater crocodile enclosures has been directly associated with the outbreaks of skin disorders such as dermatophilosis and fungal infections, which cause sores, scarring, and other flaws that reduce the value of the leather. Manolis and Webb (2005) cited that best health management practices are critical for both saltwater and Nile crocodiles; however, stocking density had different effects, with saltwater crocodiles being more tolerant of higher densities.

Ahmed (2013) stated that best health management practices have a similar impact on the leather quality of saltwater and Nile crocodiles, genetic improvement programs differ greatly, affecting the success of selective breeding. Fuchs et al. (2019) cited that genetic diversity influences skin quality in both saltwater crocodiles and American alligators aligned with previous research in Nile crocodiles. However, the reaction to environmental conditions varied, with various species exhibiting varying degrees of sensitivity to habitat and climatic changes. Karthikeyan et al. (2020) researched Caimans and discovered that while comparable leather preparation processes can be used across species, variances in skin texture and quality were obvious, emphasizing the distinct qualities of each species' leather.

The comparative studies shows that there are substantial differences on how genetic, environmental, and management factors affect the leather quality of Nile crocodiles and other crocodilian species. These distinctions are critical in designing specific techniques to enhance leather quality for each species, hence improving overall understanding and management of crocodilian leather production. Recent research, such as of Chala et al. (2020), emphasizes the need of rigorous leather preparation techniques, especially in exotic species like the Nile crocodile, whose skin quality is often subjected to stricter standards in international markets.

Conclusion

The genetic factors, environmental conditions, and management practices all have a substantial impact on the quality of Nile crocodile leather. Genetic diversity and selective breeding programs are essential for producing high-quality leather as they promote desirable traits and disease resistance. Our review emphasized that there is a need to maintain a broad genetic pool for the diverse species of crocodiles. Environmental factors such as water quality, temperature, and habitat conditions are critical for skin health. Therefore, maintaining poor conditions on crocodile farms may result in skin abnormalities, and this will affect skin quality and its value. Effective management practices, such as optimal stocking densities, balanced diets, and frequent health screenings, are critical for avoiding stress, injuries, and infections. Comparative research with various crocodilian species provides useful information about best practices for enhancing leather quality across species. This analysis emphasizes the relevance of integrated approaches to improve Nile crocodile leather quality and suggests a need for additional researches into crocodile leather production.