Introduction
Brazil has occupied the second position in the list of countries with greater richness of reptile species, only behind Australia (with 864 recorded species, according to Wilson and Swan [
1], but surpassing Mexico, India, Indonesia, Colombia, China, and Peru [
2]. There are currently 732 species of reptiles known in Brazil, of which 690 belong to the Squamata (375 serpents, 248 lizards and 67 amphisbaenids); there are also six species of caimans and 36 species of turtles [
2]. A significant part of Brazilian herpetofauna has been used by traditional human populations, and some are still used by modern societies [
3]. Many stories, myths and proverbs have been generated from these relationships and also have been passed from generation to generation through oral traditions, influencing how local people relate to these animals [
4‐
7].
Products derived from reptiles (including leather, teeth, fat, meat and bones) have nutritional, ornamental and medicinal values in many rural and urban areas in Brazil and these animals are often sought after as pets and zoological attractions [
3].The Caatinga represents one of the major examples of a semi-arid environment in the Neotropical region, where it is a biome that is extremely threatened due to the unsustainable use of natural resources. In this biome, 117 species of reptiles are recorded (7 Testudines, 47 lizards, 10 Amphisbaenia, 52 serpents, and 3 alligators) [
8‐
10]. Local human populations have interacted with many of these species by attributing some utility value to them. Additionally, some species are hunted and killed due to conflicting relations with people [
3,
11‐
13]. The main reasons for the conflicts, which lead to the killing of reptiles, include attacks on livestock and risk to human lives.
The cultural richness of the local population and its diverse interactions with the local fauna make the Caatinga an advantageous area for ethnozoological studies. These factors are fundamentally important within a socio-environmental perspective because excessive exploitation, hunting and illegal trades of wild animals are threats to some species of vertebrates of this biome [
11]. Nonetheless, over the past few decades, researchers have begun to systematically investigate the relationship between local inhabitants and the wild fauna of this region. Ethnoherpetology is a subdivision of Ethnozoology that examines the relationships between human cultures and herpetofauna [
3,
14‐
16]. Very few ethnoherpetological studies have been undertaken in Brazil [
4,
13,
17‐
22], which restricts our ability to elaborate adequate conservation strategies for many species [
3,
23].
In the last few years, the importance of the ethnobiological studies for the biodiversity conservation has been increasingly recognized [
11,
24‐
27], which is not surprising due the strong human influence on the biodiversity. Native or local people retain a wide range of biological information than can complement traditional academic knowledge in zoology, ecology, and biological conservation studies [
28‐
31]. In the case of animal conservation, it is evidenced that the perception and use ways of animals by humans are extremely relevant to the definition of possible conservation strategies. Hence, an understanding of the cultural, social, and traditional roles of the fauna is essential for establishing management plans directed towards sustainable use [
3].
In the specific case of reptiles, a recent review revealed that only five studies on ethnoherpetology were performed in the Brazilian semiarid region [
32], although some ethnozoological studies have certified the use of reptiles in the region for mainly medicinal purposes [
33‐
41]. When analysing the current panorama, it is evident that new ethnoherpetological studies are required in Caatinga, especially due to their importance in supporting management plans for the local herpetofauna. A recent ethnozoological review by Alves and Souto [
32] noted that ethnozoological research in Brazil has grown quantitatively, but these authors also highlighted that there is a clear need for qualitative improvements in the generated publications. Among the aspects that must be improved, authors have found that those studies should have a greater taxonomic accuracy, which is an aspect that is missed in most of the ethnozoological studies that have been performed. Many of the articles are based only on lists of species, which are often taxonomically incorrect or are restricted to only the popular names of the animals. In this context, the present study aims to accomplish the following: i) to elaborate a catalogue of the reptiles of ethnozoological importance from the Brazilian semi-arid region; ii) to present a brief characterisation of each species, while aiming to support new studies of ethnoherpetology in this region; iii) to present an analysis of the relationship between the local people and some native reptiles, while focusing on the utilitarian value that these human groups assign to these animals and on the conflicting relationships that are associated with this zoological group; and iv) to analyse the implications on conservation that are related to the interactions between people and reptiles in this semi-arid region of Brazil.
Discussion
Due to the adverse conditions of the environment, a large portion of the human population who live in semi-arid regions have developed a strong relationship with the resources of the local fauna [
11,
12,
27]. Ethnozoologically, reptiles are among the most important vertebrates in Caatinga because of their use or killing due to their conflicting relationships with local people. The cultural importance of these reptiles is also reflected in different myths, legends and beliefs, which, most of the time, affect these animals negatively and therefore, stimulate the fear and aversion to them.
A few reptilian species (n = 13) are used as food in the semi-arid region, for example, the large-sized lizards and snakes. The lizard
T. merianeae is the main species with food value. Although it is not common, other reptiles can also be eaten, such as
B. constrictor, I. iguana and
C. durissus. Nonetheless, the main, practical value of reptiles appears to be in popular medicine, where the products of several species of chelonians, snakes and lizards are recorded to be used as remedies for illnesses by the local population. This situation is not surprising because reptiles are among the most frequently used species in Brazilian traditional folk medicine [
33,
39,
86,
130‐
132].
Tupinambis merianae,
C. durissus,
I.iguana and
B. constrictor are the most common reptile species to be used for medicinal purposes in the semi-arid region. Particularly,
T. merianae and
B. constrictor are used because of their wide applicability in traditional Brazilian medicine [
4,
33,
133]. In the northeastern region, products from these species are used in traditional communities and are commercialised in public marketplaces in many cities [
17,
34,
38,
41,
66,
98,
106]. Recent works have investigated the use of the fat of these two species, and these studies have shown that these products may be effective for some illnesses [
134‐
136].
Different sub-products from the recorded reptiles may also be used for magical, religious and ornamental purposes and to produce handbags and belts. Mainly, non-perishable products, such as the leather of lizards and snakes and the carapace of chelonians, are used for these purposes. As was observed by Moura and Marques [
99], the use of these types of sub-products can be justified as an attempt to maximise the resources from the local ecosystems. In fact, ethnozoological studies have shown that animal parts that are improper for alimentary consumption (such as leather, teeth, carapace and skulls) are used for medicinal and magical/religious purposes and to produce ornaments or souvenirs [
137‐
145].
Despite the utilitarian value of many species of reptiles that are found in the Caatinga, a large number of these animals are killed for being considered harmful to people and domestic animals. From the 38 species that were recorded in this study, 19 (50%) are involved in a conflicting relationship with the local population, especially the serpents. Furthermore, the number of species that are associated with these types of conflicts is larger because 52 species of serpents, the group that is generally most feared and hunted by the local population, are registered in the semi-arid region. The main victims of accidents with snakes are the agriculturists who contact the serpents during their practices, and as discovered by Vizotto [
5], the Brazilian agricultural population tends to consider all serpents as poisonous, which a perception that has spread in the northeastern semi-arid region. Therefore, it is presumed that all serpents are subject to harassment by the local population. Additionally, the amphisbaenia is included in the undesirable list of animals because it has a similar morphology to serpents [
3,
68,
146,
147].
The aversive feelings for serpents are justified by the lethality risk that some species offer and motivate the indiscriminate slaughter of these animals in the semi-arid region [
11]. Between the years 2000 and 2009 in northeastern Brazil, 71,055 cases of snake accidents and 394 deaths from snake bites were reported [
148]. Only a small portion of the snake accident cases that were reported resulted in the death of the victims. However, the oral stories of accidents and deaths that were related to serpents contributed to the spread of fear of these reptiles. Because snake accidents can involve any serpent, the possibility of occurrences that are caused by non-poisonous species is high. Importantly, of the 52 serpent species that are found in the northeastern, semi-arid region, only four species are venomous. However, every snake that is found is usually killed, independent of its potential for lethality. According to Fernandes-Ferreira et al.[
7], the human perception about dangerous situations involving animals may be not directly linked to the actual threat level that these animals present. In this context, in the northeastern semi-arid region, the conflict between people and serpents are related culturally and by the lack of knowledge about the serpents regarding the occurrence of deaths that are caused by these reptiles.
Because the human population who lives in the Caatinga usually does not know if a serpent is venomous, all serpents are usually killed when found. The same aversion to reptiles that was observed in this work has been recorded in places in Brazil. Moura et al. [
22] have found that, in several regions of Brazil, there is an acceptance of a negative stereotype for all serpents, which are generally considered to be "dangerous animals". This situation, which is associated with some aspects of popular culture, can potentiate the conflicts between human beings and serpents [
3,
149,
150] and negatively influence how people interact with animals from this group [
5,
151].
Although reptiles are killed because of this conflicting relationship, sub-products of these slaughtered animals may be used in different ways by local inhabitants. Thus, a paradoxical situation occurs in that the products of a dead species, although it is considered harmful, can be used by people. For example, the sub-products of “teiús” (
T. merianae), which are commonly killed to prevent them from eating eggs and chicks, are used as ornaments and in popular medicine [
34,
36,
152,
153]. Venomous snakes, such as the rattlesnake (
C. durrisus), coral (
M. ibiboboca) and jararaca (
B. erythromelas), are killed as a precaution; therefore, while they can attack domestic animals or people, and their sub-products (e.g., rattle or fat) are used for mainly medicinal purposes [
86].
As discussed before, the interactions of the population with reptiles that are found in Caatinga are varied, and such relationships have obvious implications for the conservation of the herpetofauna from this biome. In this context, ethnoherpetology studies are crucial because they serve as subsidies for guiding strategies for the handling and conservation of reptiles in different areas.
The interaction between people and reptiles has been studied in Caatinga [
32], but is restricted to only a few localities and States. Another problem is that many ethnozoological studies that are carried out in Brazil and other countries highlight only the vernacular names or the identification of a species is made through “
taxonomic clues” [e.g. [
154‐
156], which is an alternative resource for obtaining information. Often, this method can induce serious taxonomic mistakes [
157]; therefore, it must only be used when a species cannot be adequately identified and as a last resource.
The need for greater taxonomic severity in ethnozoological studies has been emphasised [
32], and suggests that researchers collect samples of specimens for every species that is recorded in their research. This method will allow for standards of use, and the interactions between people and other animal species in different localities of the semi-arid region can be confirmed by ethnozoologists, taxonomists, and biologists.
The importance of voucher specimens in ethnobiological investigations has been repeatedly emphasised [
158,
159]. A well-developed ethnozoological study, which includes a collection of voucher material, contributes to the quality of the research and can subsidise zoological research in all related themes (e.g., taxonomy, zoological inventories and biogeography). This method can also enable the recording of new species and the broadening of the geographic distribution of previously described species [
157]. Silitoe [
160] related the discovery of the hilideo,
Litoria bulmeri, to an ethnoherpetological study by the anthropologist Ralph Bulmer, who was honoured by the nomination of the species. This author highlights that, in his research, which was carried out in New Guinea, he collected a new species of micro-hilideo (
Choerophryne sp.) that was not formally described because only one specimen was found. Several authors have highlighted the role of ethnozoology as an important tool for making inventories and enriching ecological surveys [
11,
31,
161].
Because different interactions between people and reptiles in the northeastern semi-arid region may have ecological implications on the natural populations of those species, there is an urgent need to implement actions that can control the interactions that negatively affect the involved species. Furthermore, these actions must take into account the cultural, economic, social and ecological aspects of the local human populations. The use of wild animals must be directly addressed, and educational programs that are directed towards all associated actors should be initiated. Environmental education programs that aim to create an environmental, national culture that supports the protection of these species could potentially change the attitudes of people regarding those reptiles. As pointed by Alves et al. [
162], these programs could be carried out locally by trained community organisers in areas where the species are more exploited or through environmental education programs that are linked to Brazil’s national curriculum. This idea is particularly feasible because public schools are organised nationally by the federal government [
162]. The implementation of activities of environmental education can increase the awareness of the importance of snakes, instructing those who still consider them intrinsically harmful [
3,
22]. Poughet al. [
163] emphasize that human education is urgently needed at all levels to help maintain viable populations of reptiles. Training in areas such as habitat protection, wildlife management, and conservation biology is needed — especially in tropical countries where most reptile species are found. The success of conservation and management programs ultimately depends on how well these programs are tailored to the interests and needs of the people where the threatened and/or endangered animals live.
Several factors have contributed to the decline of reptile populations in Brazil, and the direct consumption of these animals and negative interactions because of conflicts are only a part of the larger problem [
3,
4]. In the semi-arid region, non-sustainable human activities, such as slash and burn agricultureand the continuous use of native pastures for goat and cattle, are causing huge-scale environmental impoverishment in the Caatinga biome [
164]. In dry regions, climate change will also interact with human activities to increase the risk of desertification [
49,
165]. The hunting of wildlife must be considered an anthropogenic pressure, like the loss of habitat [
11,
12]. The extinction of species and the reduction in the number of species has ecological consequences [
166]. Because the reduction or local extinguishing of a species can result in a series of serious, negative impacts that mainly occur in the food chain [
167‐
169]. A decrease in the populations of serpents can generate uncontrolled populations of rodents, which could cause plagues and damage the health of human beings, agriculture and the wild-food chain [
7]. Furthermore, the slaughter of ophiophagous serpents may cause an increase of the population of poisonous snakes [
170].
Strategies for conserving the herpetofauna of the Brazilian semi-arid region must reconcile and integrate human and conservation needs. Within this context and to achieve sustainability in the use of wild species, it is necessary to establish which species are being captured and to understand the socioeconomic and cultural significance of their use and/or commercialisation. Because a wide variety of threats to reptiles exist, education and enforcement programmes must be combined with programmes that can protect wildlife habitats, which will benefit reptiles and other animal groups.