Weibchen-Gap bei ausgestopften Tieren in Museen

Eine neue Meldung zeigt den schlechten Stand der Gleichberechtigung:

In den internationalen naturkundlichen Sammlungen sind Weibchen bei den ausgestopften Tieren unterrepräsentiert. Dies geht aus einer Studie hervor, die am Mittwoch in der jüngsten Ausgabe der „Proceedings of the Royal Society B“ veröffentlicht wurde.

Die Auswertung von fast 2,5 Millionen Exponaten aus großen Naturkundemuseen in London, Paris, New York, Washington und Chicago ergab, dass nur 40 Prozent der Vögel weiblich waren. Besonders niedrig fielen aber die Anteile bei einigen Spatzen (knapp zehn Prozent), den schwarzen Fliegenschnäppern (11,5 Prozent), bei Fledermäusen (knapp zehn Prozent), Schafen und Wieseln (je 24 Prozent) aus. Bei den Paarhufern waren es weniger als 40 Prozent, obwohl dort die Weibchen in der freien Wildbahn eindeutig die Mehrheit bilden.

Das Ungleichgewicht lässt sich offenbar nicht ausschließlich mit der größeren Farbenpracht männlicher Vögel oder mit den beeindruckenden Hörnern, Geweihen und Stoßzähnen bei einigen männlichen Säugetieren erklären.

„Wir hatten schon vermutet, dass wir eine gewisse Bevorzugung von Männchen feststellen würden“, sagte Natalie Cooper vom Museum für Naturgeschichte in London. „Denn Wissenschaft wird von Menschen gemacht – und Menschen bringen eine tief verwurzelte Bevorzugung männlicher Wesen mit.“

Man muss natürlich quasi intersektional fragen: Ist es günstiger weniger ausgestopft zu werden oder den Kindern/Besuchern weniger Exemplare eines Geschlechts zu zeigen.

Immerhin findet sich in englischen Berichten etwas mehr dazu:

Showing that there is a skew in natural history collections is one thing, but figuring out where it comes from is just as important.

‚We were then interested in trying to work out why there is this bias, because obviously curators don’t just throw away the female specimens,‘ explains Natalie. ‚It must be something to do with how they were collected.

‚That could be either passive, so something to do with how male and female animals behave in the field, or it could be active whereby collectors are deliberately choosing to target males.‘

Male and female animals can and do behave differently in the wild. In some species, for example, males may range more widely and so could be more likely to fall into traps, or maybe their more conspicuous nature means that males are more likely to be spotted.

‚It is really hard to collate data on the passive explanations,‘ says Natalie. ‚Although from what we can tell there are not more males in most natural populations. In fact, even though many wild populations are female-skewed, we still find lots more males in the collections, so it does seem like there is some active choice going on.‘

The data showed that among mammals, collectors were more likely to select large individuals with some form or ornamentation or weaponry such as horns, antlers, mains or tusks. In birds, size was not as important as colouration, as it was the more brightly feathered individuals that were more likely to be collected.

Where you have birds in which the female is more colourful and bigger than the males, however, there are more females than males in the collections.

On the surface, a slight bias towards males in museum collections might not seem like much of an issue. But there are many aspects of a species‘ biology and behaviour that are affected by an animal’s biological sex.

At a basic level, if a study is looking at the taxonomy of a species and there are significant differences between males and females in their morphology, any bias towards the males could result in it being difficult to identify females down to species levels, as females are underrepresented in collections.

These biases can go even deeper. For example, males can be more susceptible to parasites as testosterone inhibits the immune system. Where collections are sex-biased, research looking into infection and immunity within a species could be skewed.

As research is advancing into more technical analyses, these biases can cause significant differences. Stable isotope ecology can use the chemicals found in tissue to figure out where an animal may have been living or migrating based on what they were eating during their lifetime. But some species may have sex-segregated diets, meaning that you cannot draw inferences about a species in general if the underlying data is overrepresented by one sex.

‚You’d like to hope that visiting researchers would come to the Museum and are selecting specimens with a mind to getting an equal number of males and females,‘ says Natalie.

‚But often when people are doing big studies, they might not even consider the sex. They are more interested in getting as many species represented as possible, or in some cases they might not have a choice due to a limited number of specimens for some species that are available in the first place.‘

Ein Teil wird sicherlich schlicht damit zusammehängen, dass Museumsplatz begrenzt ist und Museen Leuten etwas besonderes zeigen wollen und da die imposanten Hörner der Männchen oder deren farbenprächtiges Federkleid einfach mehr hermachen, gerade wenn man überlegt, was man ausstellt und was nicht. Ein – langweiligeres – Weibchen daneben zu stellen ist sicherlich in den extremeren Fällen interessant, aber in der Fülle nicht.

Aus wissenschaftlicher Sicht mag es in der Tat interessanter sein ein Männchen und ein Weibchen vorzuhalten. Aber dazu müsste man die Weibchen auch anderseits nicht in die Besuchervitrinen stellen.