Male grey seal commits fatal sexual interaction with adult female harbour seals in the German Wadden Sea

Simon Rohner,Stephanie Gross,Amir Abdulmawjood,Ludwig Haas,Jutta Verspohl,Ursula Siebert,Kirsten Hülskötter,Peter Wohlsein,Madeleine Plötz

doi:10.1038/s41598-020-69986-w

Simon Rohner, Stephanie Gross + Show 7 more

Open Access

https://doi.org/10.1038/s41598-020-69986-w

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Abstract

Males of several seal species are known to show aggressive copulating behaviour, which can lead to injuries to or suffocation of females. In the North Sea, grey seal predation on harbour seals including sexual harassment is documented and represents violent interspecific interaction. In this case series, we report pathological and molecular/genetic findings of 11 adult female harbour seals which were found dead in Schleswig–Holstein, Germany, within 41 days. Several organs of all animals showed haemorrhages and high loads of bacteria, indicating their septic spread. All females were pregnant or had recently been pregnant. Abortion was confirmed in three cases. Lacerations were seen in the uterus and vagina in six cases, in which histology of three individuals revealed severe suppurative inflammation with intralesional spermatozoa. Molecular analysis of vaginal swabs and paraffin-embedded samples of the vagina identified grey seal DNA, suggesting violent interspecific sexual interaction with fatal outcome due to septicaemia. This is the first report of female harbour seals dying after coercive copulation by a male grey seal in the Wadden Sea.

Highlights

There are three main forms of how males sexually coerce females in animal societies: intimidation, harassment and forced copulation[1]
In marine mammal polygynous mating systems though, the male dominates the mate choice, whereas the female contribution can be regarded as m inor[17]
Septicaemia with β-haemolytic streptococci and/ or E. coli is an important cause of death of adult harbour seals from German waters, which in many cases is the result of major pathologies such as gastritis, intestinal volvulus or mastitis

Summary

Introduction

There are three main forms of how males sexually coerce females in animal societies: intimidation (punishment for denial of mating), harassment (increase of costs for females if they refuse to mate) and forced copulation (use of superior speed or physical strength to copulate with the female by force)[1]. Young adult male grey seals have been witnessed to engage in interspecific mating attempts on the Island of Helgoland in the German North Sea, but related genital injuries or abortion were not d ocumented[43]. This case series from the Wadden Sea for the first time describes morphological and molecular findings in pregnant female harbour seals after copulation with a male grey seal with subsequent fatal septicaemia, likely due to genital lacerations

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