Bats are mammals of the Order Chiroptera. They are highly adaptable to several habitats and their ecology makes them vulnerable to predators. Bats are a common prey of snakes, but description of this kind of predation are rare. This study describes the event of predation of an Epicrates cenchria on a Desmodus rotundus, in a cave in Tena, Ecuador. Records of Desmodus rotundus are known from caves just as Epicrates cenchria. Castillo Cave has a total mapped length of 450 meters. The phase of constriction lasted for 10 min 2 s, a duration superior than other studies, due to the size of Desmodus rotundus. The terrestrial locomotion behavior of D. rotundus, makes it an easy target for E. cenchria. The predation event occurred on the floor, a rare case, which has not been described in other events of predation in caves. The cave is located in a disturbed habitat, because it is irrigated by wastewaters. But both species seems to be adapted to the environment. This study confirms that predation of bats in caves by snakes does occur.

Bat predation, boids, behavior, attack

Bats are mammals of the Order Chiroptera. They are highly adaptable to several habitats: trees (Jachowski et al. 2016), under plantain leaves (Rodríguez-Herrera et al. 2011), caves (Zortea et al. 2015), human settlements (Whitaker et al. 2006, Streicker et al. 2013), etc. Like most animals, they are not predator free. There is a list of enemies mentioned in the literature: monkeys, loris, mustelids (weasels), minks (Goodpaster and Hoffmeister 1950), raccoons, opossums, cats and even bats themselves. Mikula (2015) recently published a literature review of different fishes (such as salmons, catfishes and sharks) that prey on bats; and amphibians such as Bufonidae, Hylidae and Leptodactylidae, prey on bats too. Giant centipedes were also observed killing bats in a cave in Venezuela (Molinari et al. 2005). Spiders have been recently suggested that their predation on bats is not that uncommon (Nyffeler and Knörnschild 2013). But the most common predators are birds and snakes (Hill and Smith 1984, Mickleburgh et al. 1992). Within birds we can mention raptors such as Accipiter tachiro, Aquila walhbergi, Falco subbuteo, hawks (Lee and Kuo 2001) and owls (Julian and Altringham 1994) such as Asio stygius (Motta Junior and Taddei 1992), and Tyto alba (Vargas et al. 2002), but there are events of other types of birds such as Momotus momota preying on a bat (Chacón-Madrigal and Barrantes 2004). Within snakes we can mention the case reported by Hammer and Arlettaz (1998), another in western Iran by a Colubridae (Sharifi et al. 2014). Esbérard and Vrcibradic (2007) made a review of recorded cases for the neotropical region, but we can also name a more recently case of Hemorrhois hippocrepis preying on Plecotus austriacus and on Eptesicus serotinus (Schreber, 1774) / Eptesicus isabellinus (Temminck, 1839) (Garrido-García et al. 2013). Two observations were reported in caves in Mexico where snakes caught bats hanging off the roof (BBC 2014, BBC Earth 2014).

Desmodus rotundus (common vampire) is one of three sanguivorous bat species (Simmons 2005, Kwon and Gardner 2007), that habits mainly in caves but also can be found in tree holes (Pozo and Cueva pers. comm.). Normally they attack their prey flying stealthy and perching on the dorsal face of large mammals like cows, tapirs, deer and peccaries (personal observations). D. rotundus is distributed from North of Tamaulipas and Sonora (México) to Uruguay, northern Argentina and central Chile (Greenhall et al. 1983). In Caribbean Islands is found only in Trinidad (Mancina, pers. com.) and Margarita Islands (Wilson and Reeder 2005). Ecuadorian subspecies belong to Desmodus rotundus rotundus (Greenhall et al. 1983) which it has been recording in all geographic altitudes zones (Albuja-V et al. 2012). Desmodus in the day rests perching on the roof of the caves, but occasionally are found walking on the floor when they are accidentally dropped from roof (Wilmer E. Pozo-Rivera Observations). Over the floor Desmodus recently awake, walk helping with their legs and elbows.

Epicrates seems to be a major threat to bats on the neotropics. Half of the records published on the review made by Esbérard and Vrcibradic (2007) involving boid snakes species were Epicrates sp. Epicrates cenchria is endemic to Central and South America (McDiarmid et al. 1999). Ecuador has the subspecies Epicrates cenchria gaigei (Uetz and Hallermann 2016). It is described as a medium sized (Duellman 1978, Ross and Marzec 1990) terrestrial nocturnal snake (Savage 2002). Characterized by having a blue iridescence in sunlight, this viviparous snake was found in primary and secondary forest, on the ground and on the trees (Duellman 1978). But is also very common to find this species close to rivers where food is abundant (Gonzálves 2006). Birds, rodents, and bats (Lemke 1978, Medeiros de Pinho et al. 2009, Pizzatto et al. 2009) are common preys of Epicrates cenchria.

We report the first record of predation of Desmodus rotundus (Common Vampire Bat) by Epicrates cenchria (Rainbow Boa) in a cave in Ecuador.

The predation event was observed in the late afternoon of the 5^th of December 2015 during 25 minutes and mostly filmed during the regular cave monitoring of the Castillo Cave, near the city of Tena, in Napo province (Fig. 1).

Figure 1. 

Location of Napo Province and Tena as well as Castillo cave. Map of Castillo Cave in which circles represent sites where boas have been observed in the floor and crosses where boas have been observed close to the roof of the cave. The easternmost site is the one described in the text.

Predation of bats by snakes, is not that infrequent (Davis 1951, Steyn 1964, Mankins and Meyer 1965, Thomas 1974, Schatti 1984, Lewis et al. 2009). It is well registered in general websites but few are well documented and published. However reports of E. cenchria predating on bats are rare in caves the first record was documented by Lemke (1978), in a cave in Colombia and the second record was registered by Ramos Donato et al. (2012) in a cave in Brazil.

Concerning the prey, they are all, medium sized bats (Greenhall et al. 1983, Lassieur and Wilson 1989, Cloutier and Thomas 1992, Kwon and Gardner 2007). In Colombia, the bat species was Carollia perspicillata, and in Brazil Lonchorhina aurita. However, our record is the first to observe the heaviest and largest bat such as Desmodus rotundus. In Colombia, there was only one species of bat in the cave, however in Brazil’s study they registered also Desmodus rotundus, which can implied that Desmodus rotundus might belong to their diet too. It is important to notice that Desmodus rotundus has a terrestrial locomotion (Riskin et al. 2006) that E. cenchria can take advantage because E. cenchria was observed several times on the ground (T. T. observations).

The other two studies have not described the process of the event in detail. The predation took place in the three studies during the day but at different moments. In our study, the observation was at 4:50 p.m. For a nocturnal snake and for D. rotundus, is almost dusk. And D. rotundus can start their foraging activity at different times each day (Wimsatt 1969), and the roost exist can be influenced by human activity or weather. If it is cloudy, the weather during observation, the foraging activity of both individuals can start earlier. The constriction lasted for 4 minutes in Brazil, while in our study it lasted for 10 minutes and 2 seconds. This can be due to the size of D. rotundus. Also, in relation to the environment, the caves are located close to rivers which corresponds to the snakes ecology (Gonzálves 2006). Nevertheless, the water of the Castill cave is contaminated with waste water, establishing that the habitat is disturbed. However it appears that both species, Desmodus rotundus and E. cenchria, are adapted to this environment.

This is the first report for Ecuador, of Epicrates cenchria predating on a Desmodus rotundus, in a cave, and the third report for Latin America. With such a few reports, we cannot affirm that this kind of predation is common, but we suggest that a detailed study in this population would help us confirmed that this behavior is more than usual.

We are indebted to the owners of the caves visited that allowed access to their property and caves in and around Tena, and the Family Castillo in Toglo in particular. We are also grateful to the Paulo Clemente and the Municipality of Tena for the permits given. We acknowledge as well the very constructive reviews of an earlier version of this manuscript by Dr. Marco Suarez and an anonymous reviewer of Subterranean Biology and the editorial handling by Dr. Oana Moldovan. This study is also part of the research project of Toulkeridis (2014-PIC-012) of the Universidad de las Fuerzas Armadas ESPE.