Coronella austriaca (smooth snake) - mortality after prey ingestion

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32 Herpetological Bullen 152 (2020)
The smooth snake is a medium sized European species that
feeds mainly on vertebrates. Reples and parcularly
lacerd lizards are considered as the main fracon of its
diet (Reading & Jofré, 2020). Legless reples are also
preyed upon by the smooth snake, but such cases seem to
be reported less frequently (Völkl et al., 2017). On 24 May
2019 a dead specimen of Coronella austriaca was found by
the roadside in Gogolin (opolskie vovoideship, south-west
Poland) with the tail of a slow-worm Anguis fragilis scking
out of its mouth. The snake had no external signs of being run
over by car or bicycle, had no wounds and also did not look
starved or weakened. X-ray examinaon was performed with
the use of computed radiography by Konika Minolta (Regius
Model 110s) and Siemens Polydoros LX 30 lamp (Fig. 1A).
Computed tomography was performed with the use of the
Siemens 16 slice CT scanner (Fig. 1B). The body length and
diameter of both the snake and slow worm were measured
and both were weighed.
Slow worms are not unusual prey items for smooth snakes,
so mortality following ingeson of a slow worm seems unlikely
and has never been reported previously. Greene (1983), who
explored the maximum limits of the rao prey mass/predator
mass (WR), showed that the liming rao for non-venomous
snakes is WR = 0.6. Based on body measurements of the
snake we collected (SVL = 340.0 cm; tail length = 76.0 cm;
head diameter = 12 mm; weight = 14 g) and the slow worm
(SVL = 86.0 cm; tail length = 97.0 cm; body diameter = 8 mm;
weight = 3 g) giving a WR of approximately 0.2 which is far
below the threshold suggested by Greene (1983). Thus the
smooth snake which we collected should have been fully
capable of swallowing prey of the size here recorded.
Indeed, larger prey items have been recorded as
swallowed and digested by smooth snakes (Juszczyk,
1987). However, the skin of Anguis fragilis has osteoderms
(Zylberberg & Castanet, 1985); these reduce skin exibility.
This could constrain the capacity of the snake to both
swallow such prey and to regurgitate it and could eventually
lead to suocaon, which is the proposed cause of death
here. Constraints of this kind might also result in lower size
limits for swallowing prey such as slow worms compared to
other prey types and explain why juvenile slow worms are
more commonly ingested by smooth snakes than adults
(Zimmermann, 1988).
Our observaon suggests that ingeson of legless prey
could carry the high cost of increased risk of mortality.
This, in turn could provide an addional explanaon of
why ophiophagy, including cannibalism, is relavely rarely
reported in snakes (Jackson et al., 2004) and why slow worms
seem not to avoid shelters already inhabited by potenal
predators, i.e. smooth snakes (Kolanek et al., 2019) or Vipera
berus (R.J. Hodges, personal communicaon).
REFERENCES
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The Herpetological Bulletin 152, 2020: 32-33
Coronella austriaca (smooth snake) - mortality aer prey ingeson
ALEKSANDRA KOLANEK1,2*, MONIKA PASTRYKIEWICZ3, WOJCIECH BORAWSKI4
& STANISŁAW BURY1,5
1NATRIX Herpetological Associaon, ul. Legnicka 65, 54-206 Wrocław, Poland
2Instute of Geography and Regional Development, University of Wrocław, pl. Uniwersytecki 1, 50-137 Wrocław, Poland
3Gogolin, Poland
4Department of Surgery, The Faculty of Veterinary Medicine, University of Environmental and Life Sciences, Wrocław, Poland
5Instute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Kraków, Poland
*Corresponding author e-mail: aleksandra.kolanek@uwr.edu.pl
hps://doi.org/10.33256/hb152.3233
NATURAL HISTORY NOTE
Figure 1. A. Total body radiographic image in latero-lateral projecon
of a dead C. austriaca and its prey, and B. CT image of the same
animal, 3D image reconstrucon (60mAs i 130 kV, 0.6mm SD)

Herpetological Bullen 152 (2020) 33
Coronella austriaca mortality aer prey ingeson
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Accepted: 2 April 2020