Home range and habitat use of Beni anacondas (Eunectes beniensis) in Bolivia

Abstract

Understanding of snake ecology has increased over the past two decades, but is still limited for many species. This is particularly true for the recently described Beni anaconda (Eunectes beniensis). We present the results of a radio-telemetry study of nine (3M:6F) adult E. beniensis, including home range, and habitat use. We located the snakes 242 times in wet season, and 255 in dry season. Mean wet season home range (MCP) was 25.81 ha (6.7 to 39.4 ha); while mean dry season home range was 0.29 ha (0.13 to 0.42 ha). We found no relationship between home range size and either snout-vent length, weight, or sex. Beni anacondas seem to prefer swamps, and patujusal, while avoiding forest, and rice fields. However, habitat use by individual snakes seems to vary based on the habitats available within their respective home range. Notably, rice fields were avoided by most snakes, which suggests that this type of habitat is unsuitable for anaconda management.

A case of playful interaction between Bolivian river dolphins with a Beni anaconda

“…Due to their larger size, adult anacondas will often have few or no natural predators (Rivas, 2000). However, it should be noted that the Beni anaconda is likely one of the smallest species of its genus, often attaining a smaller size (mean SVL [snout‐vent length] = 1.92 m; Quintana et al, 2017) than its other counterparts, such as the Green anaconda, Eunectes murinus (Linnaeus, 1758), which attains up to 6 m (mean SVL = 3.7 m; Rivas, 2000) (Haddad‐Junior, 2012; Rivas, 2000), or the Yellow anaconda, Eunectes notaeus Cope, 1862, which attains up to 3.3 m (mean female SVL = 2.1 m; Waller et al, 2007). This smaller size could likely cause the Beni anaconda to be more vulnerable to predators.…”

“…The Beni anaconda, Eunectes beniensis , is a large‐sized aquatic Boid snake, usually attaining up to 2 m, and endemic to the floodplains of the Bolivian Amazonia (Quintana et al, 2017). The Bolivian river dolphins, Inia boliviensis , are large‐sized freshwater mammals, that reach up to 2.4 m, and are also endemic to the floodplains of Bolivian Amazonia (Aliaga‐Rossel & Escobar, 2020; Guizada & Aliaga‐Rossel, 2016).…”

Disentangling the Anacondas: Revealing a New Green Species and Rethinking Yellows

“…Both E. deschauenseei and E. beniensis overlap strongly with E. murinus in their respective distributions and habitats [30,31]. The sympatry of E. murinus and E. notaeus is less certain (Figure 1).…”

“…We know that some of these species can interbreed [24] and anecdotal reports from the pet trade suggest that their offspring may be fertile. Both E. deschauenseei and E. beniensis overlap strongly with E. murinus in their respective distributions and habitats [30,31]. The sympatry of E. murinus and E. notaeus is less certain (Figure 1).…”

The home range of adult Phrynops geoffroanus (Testudines, Chelidae) in relation to sex and body mass

“…Understanding how home ranges are arranged in the landscape helps us to identify the most important habitat traits influencing the ecology of a given species (Powell 2000). For example, we can study which habitat traits lead individuals to select or avoid a certain place (Sung et al 2015;De la Quintana et al 2017). Besides, assessing the degree of overlap between home ranges could reveal mating sys-them with multiple males (Harless et al 2009;Bower et al 2012).…”