The study of diet may help to predict the consequences of ontogeny and sexual size dimorphism in resource use. Although diet changes are expected in dimorphic species, ontogeny can be a factor in determining the degree of diet variation within a species. We studied large sexually dimorphic predator, the Yellow anaconda Eunectes notaeus, to learn how influences of sex and size on diet might lead to intersexual niche divergence, therefore avoiding intraspecific competition. We tested the consequences of sexual size dimorphism via two foraging metrics: prey size and feeding frequency. To test the consequences of ontogeny on trophic niche metrics, we related changes in feeding frequency and maximum prey size to increase in anaconda body size. Finally, we tested whether diet composition changed between sexes to the point where it could lead to reduced competition. While females (the larger sex) did eat larger prey compared to males, this effect disappeared when we removed the effect of body size. Females ate more frequently than males, even with body size effect was removed. Predator‐prey size ratios were positively affected by maximum prey size, and as expected from foraging theory, did not increase minimum prey size. Feeding frequency did not display any ontogenetic effects. While diet composition varied between sexes, overlap is high. This indicates that variations in resource use as a product of sex‐based differences in size are negligible in Yellow anacondas. Although females feed more frequently, this may be an effect of the greater energetic costs of reproduction. Ontogeny has a positive effect on maximum prey size, though this is a general trend, and has already been demonstrated for several other species. Finally, understanding of sex‐based changes in resource use will be improved if it can be determined whether such phenomena are consequences rather than causes for sexual size dimorphism.

Sustainable wildlife management is necessary to guarantee the viability of source populations; but it is rarely practiced in the tropics. The yellow anaconda (Eunectes notaeus) has long been harvested for its leather. Since 2002 its harvest has operated under a management program in northeastern Argentina, which relies on adaptive management practices, that limit the minimum body length permitted for harvesting, the number of active hunters and the length of hunting seasons. Here we investigated the effects of yellow anaconda harvest on its demography based on 2002–2019 data and show that exploitation levels are sustainable. The gradual reduction in annual hunting effort, due to a decrease in the number of hunters and hunting season duration, reduced the total number of anacondas harvested. Conversely, captures per unit effort increased across the study period. The body size of anacondas was not influenced by the harvesting, and more females than males were caught. We also found that a decrease in mean temperature positively influenced anaconda harvest and the capture of giant individuals. Because sustainable use is a powerful tool for conservation, and anacondas are widespread in South America, these discoveries are highly applicable to other species and regions.

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Sustainable wildlife management is required to guarantee source species viability; however, it is practiced rarely in the tropics. The yellow anaconda (Eunectes notaeus) has a long history of being harvested for its leather. Since 2002 its harvest has operated under a management program in northeastern Argentina, which relies on adaptive management through limiting the minimum anaconda length, number of hunters and restricting the hunting season. We investigated the effects of the anaconda harvest on its biological parameters based on 2002-2016 data. Here we show that the levels of species exploitation are sustainable. The gradual reduction in the annual hunting effort, due to a decrease in number of hunters and hunting season duration, reduced the total number of anacondas harvested. Conversely, captures per unit effort increased across the study time-period. There was no variation in the mean length of anacondas harvested, or in largest anaconda sizes. Though more females than males were caught, the sex ratio did not vary significantly. We also found that a decrease in mean temperature positively influenced anaconda harvest and the captures of giant individuals. Because sustainable use is a powerful tool for conservation, those discoveries are highly applicable to other species and regions.

Adelphobates castaneoticus uses the woody husks of Brazil nut trees, Bertholletia excelsa, (without nuts and filled with water) as oviposition sites. Three specimens of A. castaneoticus were found near Brazil nut trees in Novo Progresso, Pará State, Brazil. This record increases the distribution this species more than 500 km to the southwest.