Herpetology Notes, volume 12: 401-403 (2019) (published online on 15 April 2019) Observation of Adder, Vipera berus (Squamata: Viperidae) preying on Least Weasel, Mustela nivalis (Carnivora: Mustelidae): an overlooked feeding habit Henrik Bringsøe1,* During the past two decades two comprehensive and some comments about the rare encounter were German accounts on Vipera berus (Linnaeus, 1758) previously published in the Danish newspaper Politiken have been published (Völkl and Thiesmeier 2002; (23 July 2016). Nilson et al., 2005) e.g. providing detailed information The locality is in the western outskirts of Skagen in on the feeding biology and a wide variety of prey items the western part of the North Jutlandic Island which is which are selected by V. berus. Another thorough study formally the northernmost part of Jutland, Denmark. is that of Bea et al. (1992). A number of smaller mammal The coordinates of locality are 57.7275°N, 10.5199°E, species are listed, but with absence of members of altitude 4 m above sea level and located 120 m from Carnivora, the vast majority of which being simply too the coast of the Skagerrak which is the strait connecting large to be ingested by adders. In this paper I present a the North Sea and the Kattegat sea. It is an open beach case of an adder eating a dwarf species of Mustelidae, habitat with vegetation of grasses, shrubs of the highly namely the Least Weasel, Mustela nivalis Linnaeus, dominating Rosa rugosa and to a lesser extent various 1766. conifers. The substrate consists of sand. V. berus is On 21 June 2016 at 20:48 an adult Adder, Vipera common here. berus, was observed swallowing a Least Weasel, Though the technical quality of the photo is low, it Mustela nivalis, in the northwesternmost part of demonstrates an adult V. berus ingesting an adult M. Denmark. It was in full daylight because sunset was nivalis. As to the prey, the small body size and short tail at 22:23 on that date. The two animals were located without black tip rule out other mustelids (M. erminea, on a path of concrete flags approx. 30-50 cm from the Stoat, has longer tail with a prominent black tip). natural open vegetation. The prey was dead at the time of observation. Initially as the animals were seen, the head of the weasel was in the gape of the adder, which continued swallowing the prey (Fig. 1). After a couple of minutes the front legs and a little of the anterior part of the body had also been swallowed. Then the snake, with the prey in its nape, moved about a metre to a cover of grass where the process continued. In order to cause as little disturbance as possible the observer then walked away, but was convinced the snake continued swallowing the entire weasel. The observation was originally made by Hanne Cortsen, who documented the encounter photographically (Fig. 1). The image Figure 1. Predation of Least Weasel (Mustela nivalis) by 1 Irisvej 8, DK-4600 Køge, Denmark. an Adder (Vipera berus) in the northwesternmost part of * Corresponding author. E-mail: [email protected] Denmark. Photo by+anne Cortsen. 402 Henrik Bringsøe Although newer monographs and other detailed within the range of V. berus, namely M. erminea, Stoat publications on V. berus do not mention mustelids as (SVL 17-33 cm) (Reichstein 1993a; Grimmberger et al., prey, Schiemenz (1985) actually briefly writes that 2009), might be preyed upon by even large adders. An young least weasels (Mustela nivalis) are eaten. The exception may be juvenile M. erminea up to the size of reference for that statement is Lachmann (1890) who adult M. nivalis or slightly bigger. was, however, not cited quite correctly. Hence Lachmann (1890: 40-41) wrote: “Im Magen einer Kreuzotter fand Acknowledgements. I am indebted to Hanne Cortsen (Hellerup, Leunis einmal einen Siebenschläfer, E. F. v. Homeyer Denmark) for giving me the opportunity to publish her ein altes und ein junges Wiesel und F. Müller in Basel observation and picture of the adder eating a weasel. I thank Wolfgang Böhme, Ursula Bott and Jan Decher (Zoologisches einen schwarzen Alpensalamander”. Translation: “In Forschungsmuseum Alexander Koenig, Bonn, Germany) and the stomach of an adder Leunis once found an edible Mario Schweiger (Obertrum, Austria) for providing mammalian dormouse, E. F. v. Homeyer an old and a young weasel references. Gabriel Martínez del Marmol Marin (Málaga, Spain) and F. Müller in Basel a black alpine salamander”. That helped clarifying the data on V. latastei. Wolfgang Böhme kindly means Homeyer found one old weasel and one young prepared the pre-peer review. weasel in the stomachs of V. berus though the species of weasel was not specifically mentioned. That information References in fact stems from Homeyer (1877) which I have not Bea, A., Braña, F. (1988): Nota sobre la alimentación de seen cited before: In the summer 1874 an extremely Vipera latastei, Boscá, 1878 (Reptilia, Viperidae). On the thick V. berus was found alive. He killed and opened diet composition of Vipera latastei, Boscá, 1878 (Reptilia, it and it contained one old (or merely adult?) and one Viperidae). Munibe 40: 121–124. Bea, A., Braña, F., Baron, J.P., Saint-Girons, H. (1992): Régimes et young least weasel, M. nivalis. The author concluded cycles alimentaires des Vipères européenes (Reptilia, Viperidae) that the two weasels had been swallowed very recently. – Étude compare. Année Biologique 31 (1): 25–44. On the other hand it is better known that another Grimmberger, E., Rudloff, K., Kern, C. (2009): Atlas der Säugetiere species, Vipera latastei, has once been recorded Europas, Nordafrikas under Vorderasiens. Münster, Germany, having ingested M. nivalis. That was in the province of Natur und Tier – Verlag. Córdoba, southern Spain (Lopez Jurado and Caballero, Homeyer, E.F. von (1877): Deutschlands Säugethiere und Vögel, 1981), where V. latastei is actually rare. Later Bea and ihr Nutzen und Schaden. Selbstverlag des Verfassers (Privately published). Braña (1988) echoed that record in an investigation of Lachmann, H. (1890): Die Reptilien und Amphibien Deutschlands in gastro-intestinal contents of 75 V. latastei. Wort und Bild. Eine systematische und biologische Bearbeitung Mustelids can inflict serious injury to predators due der bisher in Deutschland aufgefundenen Kriechtiere und Lurche. their fastness, athletic nature, physical power and many Berlin, Germany, Verlag von Paul Hüttig.. Available at https:// sharp teeth. Recently Prötzel et al. (2018) presented an www.biodiversitylibrary.org/bibliography/4257#/summary and interesting case with an adult Elaphe quatuorlineata https://www.biodiversitylibrary.org/item/23043#page/9/mode/ 1up – Accessed on 12 April 2019. constricting, killing and swallowing a Least Weasel. Lopez Jurado, L.F., Caballero, M.R. (1981): Predación de Vipera The photographic documentation demonstrated that latastei sobre Mustela nivalis. Doñana Acta Vertebrata 8: 298– the weasel inflicted bite injury to snake’s lower jaw. 299. Though the authors did not provide any information on Nilson, G., Andrén, C., Völkl, W. (2005): Vipera (Pelias) berus the size of the snake, it was probably considerably larger (Linnaeus, 2758[sic!]) – Kreuzotter. In: Handbuch der Reptilien and more powerful than the adder in the current case. und Amphibien Europas. Bd. 3/IIB Schlangen (Serpentes) The adder swallowing the weasel showed no sign of III, pp. 213–292. Joger, U., Stümpel, N., Hrsg., Wiebelsheim, Germany, AULA-Verlag. injury. It is a clear indication that venom is the key, i.e. Prötzel, D., Forster, J., Krautz, T., Glaw, F. (2018): Predator versus the viperid predatory strategy of striking and killing the predator: Four-lined Snake (Elaphe quatuorlineata) feeding on prey with close physical contact of only extremely short a Least Weasel (Mustela nivalis) in Istria, Croatia (Serpentes, duration is highly advantageous against such carnivores Colubridae & Carnivora, Mustelidae). Spixiana 41: 157–159. which are very apt at defending themselves. Reichstein, H. (1993a): Mustela erminea Linné, 1758 – Hermelin. Mustela nivalis s.l. is the world’s smallest member In: Handbuch der Säugetiere Europas. Bd. 5 Raubsäuger – Carnivora (Fissipedia). Teil II Mustelidae 2, Viverridae, of Carnivora (snout-vent length [SVL] 11-27 cm) Herpestidae, Felidae, pp. 533–570. Stubbe, M., Krapp, F., Hrsg., (Reichstein, 1993b; Grimmberger et al. 2009) and Wiebelsheim, Germany, AULA-Verlag. hence the most obvious target prey of V. berus. It is Reichstein, H. (1993b): Mustela nivalis Linné, 1766 – Mauswiesel. unlikely that the second-smallest species of Carnivora In: Handbuch der Säugetiere Europas. Bd. 5 Raubsäuger Observation of Adder preying on Least Weasel 403 – Carnivora (Fissipedia). Teil II Mustelidae 2, Viverridae, Herpestidae, Felidae, pp. 571–627. Stubbe, M., Krapp, F., Hrsg., Wiebelsheim, Germany, AULA-Verlag. Schiemenz, H. (1985): Die Kreuzotter Vipera berus. Die Neue Brehm-Bücherei 332. Wittenberg-Lutherstadt, Germany, A. Ziemsen Verlag. Völkl, W., Thiesmeier, B. (2002): Die Kreuzotter – ein Leben in festen Bahnen? Bielefeld, Germany, Laurenti-Verlag. Accepted by Spartak Litvinchuk.