Feeding ecology of the Jingdong frog Odorrana jingdongensis from Vietnam

Since there is currently a lack of data on the natural history and feeding ecology of Odorrana chapaensis, which was listed in the IUCN Red List (2019), we herein provided the feeding ecology of this amphibian species is virtually lacking. We herein provide data about the diet of O. chapaensis based on the results of our field work in Ngoc Chien Commune, Muong La District and Xim Vang Commune, Bac Yen District, Son La Province, Vietnam. We used the stomach-flushing method to obtain the stomach contents of 85 individuals at two survey sites. A total of 20 prey categories with 334 items, comprising 299 items of invertebrates and 35 unidentified items, were found in the stomachs of O. chapaensis. The dominant prey items of O. chapaensis were Araneae, Polydesmida, insect larvae, Blattodea, Coleoptera, Dermaptera, Lepidoptera, Hymenoptera, and Orthoptera. The importance index for these categories ranged from 3.5% to 32.5%. Coleoptera was the category with the highest frequency of prey items; its representatives were found in 45 stomaches.

Since there is currently a lack of data on the natural history and feeding ecology of Odorrana chapaensis, which was listed in the IUCN Red List (2019), we herein provided the feeding ecology of this amphibian species is virtually lacking. We herein provide data about the diet of O. chapaensis based on the results of our field work in Ngoc Chien Commune, Muong La District and Xim Vang Commune, Bac Yen District, Son La Province, Vietnam. We used the stomach-flushing method to obtain the stomach contents of 85 individuals at two survey sites. A total of 20 prey categories with 334 items, comprising 299 items of invertebrates and 35 unidentified items, were found in the stomachs of O. chapaensis. The dominant prey items of O. chapaensis were Araneae, Polydesmida, insect larvae, Blattodea, Coleoptera, Dermaptera, Lepidoptera, Hymenoptera, and Orthoptera. The importance index for these categories ranged from 3.5% to 32.5%. Coleoptera was the category with the highest frequency of prey items; its representatives were found in 45 stomaches.

The Boulenger's spiny frog Quasipaa boulengeri Günther, 1889, is known from only Vietnam and China. It was listed as Vulnerable (VU) in the IUCN Red List and as Endangered (EN) in Vietnam Red Data Book. Knowledge about natural history of this species is virtually lacking. In this study, we analysed the diet of Q. boulengeri based on stomach contents of frogs collected from Cao Bang and Ha Giang Provinces, northern Vietnam. In addition, we also compared food contents between sexes and seasons. We found a total of 892 prey items belonging to 30 prey categories, including 11 orders of insects and four prey categories of invertebrates. There were no positive correlations between the body size of frogs and the minimum prey volume, while there were correlations between the body size of frogs and maximum prey item volume, mean prey item volume and total prey volume. The most important prey groups of Q. boulengeri were Blattidae (IRI = 40.58%), followed by Acrididae (9.27%), other Coleoptera (7.41%) and Tettigoniidae (4.95%). There was an overlap of 67.39% in the diet between males and females. Despite differences in diet compositions between the sexes, Blattidae, beetles and Acrididae make up a majority of prey for all of them. We also compared diet composition between seasons, with a higher number of prey categories recorded in the rainy season (28) than the dry season (15). Keywords: amphibians, Cao Bang Province, Ha Giang Province, insects, prey items, stomach contents

-A11 species of diurnal leaf-litter anurans in central Amazonia changed the type and size of their prey as they grew. Postmetamorphic individuals of all species ate principally mites and collembolans, and larger frogs ate larger prey of types. The shift in prey types was not a passive effect of selection for larger prey. There was a strong relationship between electivity for prey types and frog size, independent of electivities for prey size, in six of the seven species. This study showed that most species in the community had strong ontogenetic changes in diet composition and electivity for prey types, and these changes did not conform to simple models of the effects of predator size and diet quality. urnal of Herpetology, Vol. 32, No. 3, pp. 392-399, 1998 pyright 1998 Society for the Study of Amphibians and Reptiles e Ef ects of Size on the Di ts of Six Sympatric Spec es of stmetamorphic Litter Anurans in Ce tral Am zonia Change in diet with ontogeny has often been studied in fish (reviewed in Werner and Gilliam, 1984; Osenberg et al., 1992; Sheldon and Meffe, 1993). In anurans and reptiles, change in diet has been related to changes in selection for the type or size of prey (Schoener and Gorman, 1968; Pengilley, 1971; Labanick, 1976; Rose, 1976; Mushinsky et al., 1982; Christian, 1982; Dominguez and Salvador, 1990; Donnelly, 1991; Simon and Toft, 1991; Lima and Moreira, 1993). However, most of these studies have focused on one or two species (Lynch, 1985 is an exception). Consequently, little is know about change in diet with ontogeny in multi-species assemblages. However, the selection for prey size is not independent of selection for prey type because different types of arthropods have different mean sizes. The smallest arthropods available for anurans and lizards are principally mites and collembolans. The most abundant arthropods of intermediate sizes are ants, termites, and beetles, and the largest arthropods are orthopterans, butterflies, and spiders (Schoener and Janzen, 1968; Dominguez and Salvador, 1990; Lima and Moreira, 1993). Therefore, variiet ith ontogeny has often be n is (revie ed in Werner and Gilliam, et al., 1992; Sheldon and Mef e, a s and reptiles, change in diet late to changes in selection for the i prey (Schoener and Gorman, ille , 1971; Labanick, 1976; Rose, i s et al., 1982; Christian, 1982; a Salvador, 1990; Donnelly, 19 1; t, 1991; Li a and Moreira, 19 3). st of these studies have focused on s ecies (Lynch, 1985 is an exception). l , little is know about change in diet i ulti-species as emblages. e selection for prey size is not inselection for prey type because es of arthropods have dif erent . e s al est arthropods available s a lizards are principally mites ation in the taxonomic composition of the diet with the stage of growth of individuals is expected as a passive side effect of the capacity to ingest larger prey. Lima and Moreira (1993) d monstrated that the shift in prey types with growth was not just a passive effect of selection for larger prey in the leaf-litter frog, Colostethus stepheni. For that species, there was a strong relationship between electivity for prey types and frog size, independent of electivities for prey size. To test whether size-independent shifts in electivity are a general phenomenon in leaf-litter frogs or are restricted to C. stepheni, I studied the diet of postmetamorphic individuals of six species of diurnal leaf-litter frogs that occur syntopically with C. stepheni in Reserva Florestal Adolpho Ducke in Central Amaz6nia. MATERIALS AND METHODS Study Area and Distribution of the Species.-The study was conducted in a 10,000-ha tropical rainforest reserve, Reserva Florestal Adolfo Ducke (Reserva Ducke), located 25 km northeast of Manaus, Amazonas, Brazil (03?08'S; ion in the tax nomic composition of the diet ith the stage of growth of in ividuals is excted as a passive side ffect of the capacity to est larger prey. Lima and Moreira (1993) e onstrated that the sh ft in prey types with o th was not just passive effect of selection larger prey in the leaf-litter fr g, Colostethus pheni. For that sp cies, there was a st ong reionship between electivity for prey types and g size, ind pendent of electivities for prey 392 This content downloaded from 157.55.39.96 on Sun, 02 Oct 2016 05:58:51 UTC All use subject to http://about.jstor.org/terms DIETS OF SIX LITTER FROGS 60?04'W). The study was done at two sites separated by four km. The first site, described by Lima and Moreira (1993) lies along six trails (?7 km) in an undisturbed part of Reserva Ducke. The second site included a plateau and stream. I used an area of about 2 km by 200 m wide along the margins of the stream and about 2 km by 10 m on the plateau. The plateau is traversed by an unsealed forest road. Temporary pools form on the margins of the road in the rainy season. The community of diurnal leaf-litter frogs of Reserva Ducke is composed of seven species: Adenomera andreae and Eleutherodactylus fenestratus (Leptodactylidae), Colostethus marchesianus, Colostethus stepheni, and Epipedobates femoralis (Dendrobatidae), and Bufo cf. typhonius and Dendrophryniscus minutus (Bufonidae). The juveniles of all species metamorphose at ca. 6.5 mm snout-urostyle length (SUL), except for E. femoralis and E. fenestratus, which metamorphose at >8.0 mm SUL. Individuals of Eleutherodactylus fenestratus >24 mm are nocturnal. All species are active during the day and can be found in the same place foraging for arthropods over the leaf-litter. At both study sites, five of the species (D. minutus, C. marchesianus, E. fenestratus, A. andreae, and B. cf. typhonius), are usually found near streams, especially in the dry season. In the rainy season, those species have wide distributions and may be found on valleys, slopes, and plateaus. Epipedobates femoralis occurred only on the plateau in the second site in both the rainy and dry seasons. Food Availability.-All species forage principally on the surface of the litter. However, litter arthropods migrate between the surface and the first few centimeters of litter depending on climatic conditions. The pool of invertebrates generally available was estimated from samples of litter and soil to a depth of 5 cm, collected with a 6.4 x 6.6 cm soil corer. A total of 144 samples were collected from February 1991 to March 1992 (except September and October 1991). The invertebrates were extracted in Berlese funnels for eight days and identified to order or family. The samples were collected at different points distributed throughout the length of each trail in each month so that all areas in which frogs were collected or observed were sampled. There was little variation in the proportion of prey types in samples of availability throughout the year. Therefore, arthropod availability used in analyses of electivity was based on the pooled sample for the whole year. The extraction of invertebrates from litter samples using Berlese funnels, when not done with care, could sample 10% or less of mites and collembolans in the sample (Toft and Levings, 1979). In this study, extractions were done slowly and carefully, and mites constituted 65% of the fauna and collembolans 28%, proportions similar to those encountered in detailed studies (Simon and Toft, 1991). Analyses of Diet.-A total of 1065 frogs were used for the diet analyses. Approximately 20% of these were collected during 2-3 d periods each month from April 1988 to October 1989 (except June and July 1989) and about 60% were collected from January 1991 to March 1992. I walked all trails in both areas, capturing every frog within one meter of the center of the trail between 0800h and 1700h. The remainder of the nimals wer collected from March 1993 to May 1995. During that period, I walked all trails capturing only fr gs in ize classes that were lacking from the origi al collections. The animals were killed immediately and fixed in 10% formalin. Their lengths, from the tip of the snout o the posterior end of the urostyle (SUL), were measured with Vernier callipers after preservation. For ana yses of di t, I used only items in the stomach. They were sorted into prey categories (generally orders or family). Prey categories that contributed less than 10% (mass) of the diet of all size ca egories were grouped as other invertebr tes or larvae, For analyses of electivity, I considered only seven prey categories (Collembola, Acarina, Formicidae, COA, Isoptera, insect larv e, and invertebrates). The COA category included Coleoptera, Orth ptera, and Ar neae. Those categories were combined based on the supposition that sit-andwait foragers will be more efficient in capture of mobile species of those prey types (Huey and Pianka, 1981; Toft, 1985; Pough and Taigen, 1990). I d d not group this category with other invert rates, because it may contain important independent information about the diet composition of the species. Sizes of prey were measured under a dissecting microscope with a gridded eyepiece. In the case of disarticulated items, the original size of the prey was estimated by comparison with a reference collection. Wet masses (excess water removed with blotting paper) of the preserved animals were determined on a digital balance accurate to 0.0001 g. I estimated the masses of animals that were lighter than the limit of reading of the balance by grouping 10-100 preserved arthropods of similar size from the same taxon, weighing them, and calculating the mean mass. Statistical Analyses.-Electivities were based on numbers of individuals rather than mass and calculated by the method of Jacobs (1974): D = (Rk Pk)/[(Rk + Pk)(2RkPk)], where Rk is the proportion of prey k in the stomach contents and Pk is the proportion of prey k 393 This content downloaded from 157.55.39.96 on Sun, 02 Oct 2016 05:58:51 UTC All use subject to http://about.jstor.org/terms

This study investigated the influence of seasonality on diet and foraging behavior of the whiptail lizard Ameivula (Cnemidophorus) ocellifera in the Caatinga of northeastern Brazil. Diet composition was identified through stomach analysis of lizards collected monthly by active search during 2009 (rainy and dry seasons) and half of 2010 (rainy season). Foraging behavior was investigated during one rainy and one dry month of 2012, allowing us to determine the percent of time spent moving (PTM), number of movements per minute (MPM), and number of successful attacks on prey by lizards during foraging activity. Analysis of stomach contents showed significant seasonal differences in diet: insect larvae, Coleoptera, and Orthoptera predominated during the two rainy seasons (2009 and 2010); insect larvae, Hemiptera, Araneae, and Orthoptera predominated in the dry season. Prey movement index was lower during rainy seasons, mainly because of more insect larvae consumed during those periods. Population niche breadth was broader in the dry season, but individual niches did not differ significantly between seasons. When foraging, the average PTM was 61.1 ± 15.1%; MPM was 2.03 ± 0.30; and prey items captured/min was 0.14 ± 0.14. PTM for A. ocellifera was similar to values found for North American whiptails (Aspidoscelis), but MPM was relatively higher. Seasonal differences were observed in PTM, which were significantly higher in the rainy season. This difference may represent a behavioral adjustment in response to differences in seasonal food availability.

As a result of our field surveys, a new population of the Dao Frog, Amolopsdaorum (Bain, Lathrop, Murphy, Orlov & Ho, 2003), was found in Son La Province, northern Vietnam, and its identification was based on molecular and morphological analyses. To date, knowledge about the natural history of this species is scarce, including data on its dietary ecology. Using the stomach-flushing method, we analyzed stomach contents of 132 individuals (81 males and 51 females) of A.daorum. We found 501 prey items (458 invertebrates, one vertebrate, and 15 unidentified items), belonging to 11 insect orders (Blattodea, Coleoptera, Dermaptera, Diptera, Hemiptera, Hymenoptera, Isoptera, Lepidoptera, Odonata, Orthoptera, Plecoptera), insect larvae, Araneae, Opiliones, Mollusca, Polydesmida, Scolopendromorpha, and a frog. The dominant prey items of the species were Coleoptera (19.16%), Hymenoptera (17.76%), insect larvae (16.57%), Hemiptera (9.98%), Araneae (7.98%), Diptera (6.99), and Orthoptera (5.79%). The importance index for these categories ranged from 5.61% to 18.45%. Hymenoptera and Coleoptera were the categories with the highest frequency of prey items, found in 55 and 54 stomachs, respectively. There was an overlap of 82.83% in the diet between males and females. Coleoptera, insect larvae, Hymenoptera, Araneae, and Orthoptera represented the most important prey categories for both sexes.

Summary A total of 966 cichlids, Cichlasoma urophthalmus, was sampled from three karstic water bodies (cenotes) in the Yucatan Peninsula. Sex ratio was not different from 1. Specimens with ripe eggs were found during the dry and rainy seasons in the inland cenote and during the dry, rainy, and north winds seasons in the two wetland cenotes. With respect to relative fecundity, data show the C. urophthalmus inland population as two- to three-fold greater (53.1 ± 27.7) than the wetland populations (15.7 ± 5.1 and 18.2 ± 3.1). This is attributable to the different breeding strategies of C. urophthalmus populations inhabiting these two types of cenotes. In particular, the ichthyofauna from the two wetlands showed not only higher species richness (17 and 16 species) but also a higher number of potential predators (nine and eight species) as compared to the inland cenote (six species; two potential predators). It is hypothesized that C. urophthalmus adjusts its clutch size and extends its breeding periods as a response to riskier sites as compared to more secure ones; a higher competition for breeding sites and to increased fishing mortality.

Seasonal rainfall affects tropical forest dynamics and behavior of species that are part of these ecosystems. The positive correlation between amphibian activity patterns and rainfall has been demonstrated repeatedly. Members of Dendrobatidae, a clade of Neotropical dartpoison frogs, are well known for their habitat use and behavior during the rainy season, but their behavior during the dry season has received little attention. We studied habitat use and diet of the dendrobatid frog Dendrobates tinctorius in French Guiana during the rainy and dry seasons. Unlike many other dendrobatid frogs, D. tinctorius does not maintain territories for the entire rainy season. Both sexes colonize recently formed canopygaps and stay in these forest patches for only a few weeks. The frogs in these patches consume a great diversity of prey, consisting of ants, beetles, wasps, insect larvae, and mites. During the dry season, frogs move to retreat sites in mature forest, such as palm bracts and tree holes. The frogs are less active and consume fewer prey items in the dry season, and they consume fewer wasps and insect larvae, but more termites. Ants are the most common prey items during both the wet and dry seasons. We discuss the effects of shifts in seasonal habitat use on the territorial behavior of dendrobatid frogs.

Introduction: The fish of the Sciaenidae family are important for commercial and subsistence fishing on the Colombian Pacific coast. However, it is unknown how their trophic habits vary between climatic seasons. The objective of this research was to determine the variation of diet and the presence of microplastics (MP) in species of this family and its relationship with the environmental dynamics of the water of the Buenaventura Bay, colombian Pacific. Methods: Samples were taken in dry and rainy season of 2020 and 2021 in the internal and external areas of the bay. A total of (144) individuals of the species Larimus argenteus, Stellifer zestocarus and Stellifer melanocheir, were sampled using artisanal trawling and their stomach contents were classified into five categories of food prey corresponding to crustaceans (shrimp, crabs, isopods), fish, nematodes, detritus (organic material), and MP microplastics (fibers and fragments). The analysis of stomach contents used as trophic parameters, the frequency of occurrence (% FO) and the relative importance index (IRI %) of prey. These stomach contents were related to environmental variables salinity (PSU), temperature (° C), pH, dissolved oxygen (mg l−1) and water transparency (cm) through GAM models. Results: In general, Sciaenidae fish consumed mainly crustaceans in dry season. The fish as prey supplement their diet in both periods, but their consumption intensifies in rainy season. The detritus is consumed mostly in dry season, being able to relate to the consumption of crustaceans, while the nematodes are consumed mainly in rainy season, associated with the greater consumption of fish. L. argenteus consumed more crustaceans in dry season, associated with high salinities and low temperatures, while in rainy season the intake of fish increases. While, in low temperatures increased the intake of detritus in S. zestocarus. The highest MP content in L. argenteus was found in low salinity and pH, associated with rainy season and internal zone. Conclusions: The study suggests that the diet of Sciaenidae fish is influenced by the estuarine supply, subject to environmental variation.

Diet is a fundamental aspect of the ecological niche of amphibians and usually varies intra-specifically in response to extrinsic environmental and intrinsic individual factors. Phenotypic variations among individuals can generate intrapopulation differences in trophic resource use, which could have important ecological and evolutionary implications in amphibian populations. Here, we studied the intrapopulation dietary variation of the frog Pseudopaludicola pusilla in an anthropic savanna of the Colombian Caribbean region, considering the effects of seasonality and sex on the size, amount, prey composition and dietary individual specialization. We collected 44 adult frogs during the dry season and 46 during the rainy season and analyzed their stomach contents to determine their dietary composition. Our results indicate that P. pusilla is a generalist and opportunist predator, feeding mainly on insects of the orders Orthoptera, Coleoptera and Hymenoptera, which were the most important prey categories due to their numeric, volumetric and frequency contributions. We observed seasonal variations regarding volumetric prey composition and the importance value of each prey category in the populational diet. Individuals of P. pusilla consume more prey items during the rainy season and bigger prey during the dry season, but the volume of stomach contents did not vary seasonally. Males and females of P. pusilla consumed a similar number of prey items, but females ingested more voluminous prey and had greater volumes of stomach contents than males. Additionally, we observed a pattern of dietary individual specialization, which was not related to morphological trade-offs and did not differ among seasons. These findings contribute to the understanding of the seasonal dynamics of the use of trophic resources by anurans and the effect of sex on dietary characteristics of P. pusilla, in environments strongly influenced by climatic seasonality.

The Black-spotted Paddy Frog (Micryletta nigromaculata) was recently discovered from northern Vietnam. Due to its restricted distribution in limestone karst forests and habitat degradation, the endemic species has been listed as “Endangered” in the IUCN Red List. However, knowledge about the natural history of this species is scarce, including data on its dietary ecology. Recent field surveys revealed new populations of M. nigromaculata occurring in Son La Province, northwestern Vietnam based on morphological analysis. Using the stomach-flushing method, we analyzed stomach contents of 45 individuals (21 males and 24 females) from a total of 52 captured frogs because stomachs of six males and one female (13.5%) were empty. The food spectrum of M. nigromaculata comprises 12 types with a total of 691 prey items (687 invertebrate items and four unidentified items), belonging to six insect orders, larvae and Araneae. Similar to other species of the family Microhylidae, M. nigromaculata is also identified as an ant (Formicidae) – termite (Rhinotermitidae) eating specialist with distinctly higher percentages of occurrence frequency (F = 65 %), number of prey items (N = 80 %), and importance (Ix = 75 %) than those of remaining types. The Simpson diversity index of 0.939 shows a high abundance of food prey in the wild, and the Evenness index of 0.536 suggests biased consumption of feeding selection for M. nigromaculata.

Recent field surveys revealed a new population of the Menglian Paddy Frog (Micryletta menglienica) from Son La Province, northwestern Vietnam based on molecular and morphological analyses. The species has been listed as “Data Deficient” in the IUCN Red List. To date, knowledge about the natural history of this species is scarce, including data on its dietary ecology. Using the stomach-flushing method, we analyzed stomach contents of 45 individuals (21 males and 24 females) from a total of 52 captured frogs because stomachs of six males and one female (13.5%) were empty. The food spectrum of M. menglienica comprises 12 types of 691 prey items (687 invertebrate items and four unidentified items), belonging to six insect orders, larvae and Araneae. Similar to other species of the family Microhylidae, M. menglienica is also identified as an ant (Formicidae) – termite (Rhinotermitidae) eating specialist with distinctly higher percentages of occurrence frequency (F = 65 %), number of prey items (N = 80 %), and importance (Ix = 75 %) than those of remaining types. The Simpson diversity index of 0.939 shows a high abundance of food prey in the wild, and the Evenness index of 0.536 suggests biased consumption of feeding selection for M. menglienica.

Based on stomach content analyses of 45 specimens of Nanorana yunnanensis from Son La Province, we identified 301 prey items of 23 categories. Coleoptera is the highest frequency of prey items, found in 36 stomaches. Prey items of N. yunnanensis are more diverse in May and October with 18 catergories. Insecta larvae have the highest volume of prey items (25,45% of total volume of prey items), followed by Mullusca (19,34%), Lepidoptera (18,60%) and Coleoptera (11,27%). Important prey items of N. yunnanensis are Coleoptera (Ix Index 21,28%), Insecta larvae (15,56%), Lepidoptera (13,08%) and Mullusca (8,40%). Prey categories in the stomach of males (21 categories) are more diverse than those of females (17 categories) and sub-adults (14 categories).

BackgroundSon La Province is located in north-western Vietnam and the province contains a large area of 440,000 hectares of natural forest. A wide range of elevations and the complexity of landforms have given this province a great diversity of natural habitats and a high level of biodiversity potential. However, the snake fauna of Son La province is still poorly studied. Previous studies documented 56 species of snakes from this province.New informationAs a result of our field surveys in Phu Yen, Song Ma, Thuan Chau and Van Ho districts, we report five species of snakes for the first time from Son La Province, northern Vietnam, namely Boiga cyanea, B. guangxiensis, Lycodon meridionalis (Colubridae), Protobothrops cornutus and P. mucrosquamatus (Viperidae), with novel data about morphological characters. In addition, we provide an updated checklist of 61 snake species from Son La Province. The snake fauna of Son La Province also contains a number of species of conservation concern: 11 species listed in the Red Data Book of Vietnam (2007), four species listed in the IUCN Red List (2020) and four species listed in the Vietnam Governmental Decree No. 06 (2019).

The aim of this study was to compare testosterone concentration, body weight, scrotal circumference and age to penis detachment from days 30 to 240 in young Boer goat males (n = 22) born during the dry (n = 11) and the rainy (n = 11) seasons. In the dry season the parameters varied as follows: body weight from 3.7 ± 1.1 to 34.0 ± 4.7 kg, scrotal circumference from 7.9 ± 0.8 to 25.7 ± 2 cm, and testosterone concentration from 259.4 ± 172.4 to 4613.4 ± 2892 pc/mL. In the rainy season parameters varied as follows: body weight from 9.7 ± 2.3 to 28.1 ± 6.9 kg, scrotal circumference from 9.5 ± 1.5 to 22.0 ± 3.0 cm and testosterone from 521.9 ± 311.3 to 3417.9 ± 2021.8 pc/mL. At three months of age, 70% of animals born during the rainy season presented with penis detachment, compared to 67.6% of animals born during the dry season at five months of age. Penis detachment occurred in all males at four and seven months for animals born in the rainy and dry seasons, respectively. There was a positive correlation between testosterone concentration and body weight in the dry (r = 0.30) and rainy (r = 0.43) seasons, between testosterone and scrotal circumference in the dry (r = 0.42) and rainy (r = 0.52) seasons, and between body weight and scrotal circumference in the dry (r = 0.93) and rainy (r = 0.88) seasons. The animals born during the rainy season showed earlier development in all the evaluated parameters than animals born during the dry season. It was found that scrotal circumference is directly correlated to body weight and testosterone concentration. Keywords : Scrotal circumference, testosterone, young male goats, puberty, sexual maturity