This month, I officially started with my two-year postdoc fellowship at the Leibniz Institute for Zoo and Wildlife Research (IZW), granted by the Alexander von Humboldt-Stiftung. As of now, I am part of the Evolutionary Ecology Department, or more specifically: the Batlab, and I will study the role of personality and social associations in the movement behaviour of partially migratory noctule bats, Nyctalus noctula. In Germany they are called Abendsegler, meaning something like ‘Evening sailor’. Beautiful isn’t it? I am very much looking forward to my work at IZW and I hope to learn many new things, meet many passionate wildlife researchers and contribute some fascinating new insights into noctule bat behaviour.
Abstract of my awesome bat project:
Migratory animals vitally connect distant ecosystems worldwide, impacting key ecological processes by transporting nutrients, seeds, parasites and pathogens. As the only flying mammals, bats represent a unique and widespread group of migratory animals, serving important ecosystem functions as pollinators and pest controllers. Bats comprise one fifth of all mammal species, but little is known about their migration strategies. Yet understanding animal migration strategies provides important insights into ecosystem connectivity. Therefore, I aim to gain a better understanding of the key mechanisms that drive variation in bat migration strategies.
A single bat population can contain resident as well as migrating individuals. Such populations offer an excellent opportunity to study individual differences in migration strategies within populations. Hitherto, research on migration has mostly focused on birds, yet novel tools have recently become available to study partial migration in bats. Migration poses a trade-off: migration can lead individuals to more favourable habitats, but is also risky and energetically costly. Individuals have to balance these costs and benefits of migration and are likely to differ in how they do so. Bats fundamentally differ from many migrating bird species in key life-history traits that profoundly impact migration decisions. Knowledge about bat migration strategies, may thus lead to crucial insights into the maintenance of animal migration over evolutionary timescales.
New and improved techniques, such as non-invasive isotopic geolocation, allow for novel insights into the migration strategies of this poorly understood migratory taxon. Using this novel technique in combination with bat personality assays, social network analyses and bat banding, I will test whether individual bats consistently or plastically differ in their migration strategies and investigate the key social, physiological and behavioural factors underlying these differences.
This week I submitted a manuscript to a preprint server for the first time. This is a bit scary because a preprint is not peer-reviewed and so is missing a ‘security check’, something that always makes me feel a bit more at ease when communicating my results [but see: http://thebrainissocool.com/2017/12/19/peer-review-is-not-all-that-is-cracked-up-to-be/%5D. However, I think preprint servers are a great idea, because you don’t have to wait for months before you can finally share your results and show people what you are working on. More importantly, preprint servers provide a way, for those interested, to read your findings without having to pass a pay-wall. A version of your study will thus always stay open-access. So, I put my fears (somewhat) aside and decided to submit my recent manuscript to BioRxiv, before submitting it to a scientific journal.
In the manuscript, we describe a field experiment with wild guppies in Trinidad by which we studied foraging success in the wild. We tested if foraging success in the wild differs consistently between individuals and if these differences can be explained by individual traits such as sex and social type, but also by population traits such as sex-ratio. I think the results are very exciting and also somewhat unexpected. If you would like to find out more, then please read the preprint on BioRxiv.
Last week, June 22, a for me very important paper was published online in the scientific journal Trends in Ecology and Evolution. With this Opinion paper, me and my co-authors hope to stimulate a closer collaboration between animal social network scientists and conservation practitioners. You can read more about it in our press release below. If you are interested in reading the complete scientific article, but do not have access, please send me a message/email.
As with humans, most animals prefer to associate with some individuals and not with others. The social structure can influence how a population responds to changes in its environment. Examining social networks is a promising technique for understanding, predicting and – if for the better – manipulating this structure. However, whereas the contribution of behavioural biology to conservation is already well recognized, the usefulness of animal social network analysis as a conservation tool has not yet been addressed. A group of behavioural ecologists led by Lysanne Snijders from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) outlines how the understanding of relationships between animals could be applied by wildlife managers and conservationists to support their work in disease management, breeding programs, reintroductions or relocations, or for controlling problem behaviours – to name just a few.
Animal social network studies examine how the individuals of a population are socially connected, how they interact and associate. Knowledge of the social structure can help to identify the flow of information or the spread of disease, and has potential to be used as an indicator of upcoming population changes. Information of that kind would be less – or not at all – noticeable using methods purely based on population size or the observation of single individuals.
Dr Lysanne Snijders, Post Doctoral Researcher at the Department of Biology and Ecology of Fishes at IGB, describes this approach with the help of Aristotle: “The whole is greater than the sum of its parts. Combined effects of social interactions in wildlife populations do not only have important theoretical but also practical implications. Linking animal social network theory to practice can therefore stimulate the design of new practical conservation tools and generate novel insights into how animal social networks change over time.”
An example from real wildlife
For many species, it is not just diseases that can spread rapidly. Social information can also be transmitted via various routes within a group, for instance, innovative ways to search for food. In the case of the California sea lion, novel foraging strategies have led to conflict with a fishery conservation scheme. The sea lions had discovered that salmonids migrating upriver became more concentrated at a dam, making them easy prey. Unfortunately, those salmonids were endangered species. A recent study  showed that knowledge of the network structure could have helped wildlife managers to detect that at first it was only a few successful individuals who “recruited” the others, and that the selective removal of these information spreaders could have contained the problem. In this case social network analysis could therefore have assisted in protecting the endangered salmonids while culling fewer sea lions.
Snijders also suggests a possible example for how animal social network analysis could be used in conservation work in Europe: “In cases of recently reintroduced group living animals, such as the European bison, social network analyses could give insights into how a population’s long-term persistence might vary with particular behavioural processes within the group. But also into how group and individual movements might be effectively manipulated to avoid human-wildlife conflicts such as entering restricted areas like farm land.”
Perspectives for implementation
In a field in which funds and time are limited, any newly suggested approach should have a distinct added value. Not every conservation challenge that is linked to a species’ social behaviour will require a social network approach to address it. The scientists also acknowledge that their proposal has to overcome another important hurdle first: before applying the knowledge of social relationships to management practices, it should become feasible and cost-effective to collect the required data in the first place. But with technological options becoming more common and affordable, an animal social network analysis approach could increasingly become an option.
There are several methods out there that have been successfully applied to map wildlife social networks, ranging from sampling individuals at fixed locations, to walking transects, to automatically spatially tracking the animals. Rapid advancements in technology, like proximity loggers and GPS tags, allow for ever smaller animal species to be tracked, while at the same time becoming more affordable. In addition, collaborations between research institutes and conservationists might provide opportunities for sharing the costs or the technology.
 Zachary A. Schakner, Michael G. Buhnerkempe, Mathew J. Tennis, Robert J. Stansell, Bjorn K. van der Leeuw, James O. Lloyd-Smith, Daniel T. Blumstein (2016): Epidemiological models to control the spread of information in marine mammals. Published 14 December 2016. DOI: 10.1098/rspb.2016.2037
Would you consider yourself to be social? More or less social than average? And try to think back, were you always like this or did you become more or less social later in life?
I think it is safe to say that humans are a social species. In Germany, people live with 120 people per one square kilometre, in Berlin with over 4000! That we still sort of like each other tells us we have a high social tolerance. Indeed, we humans even tend to be attracted to places with other people present.
But, as you may have realized, from one person to the next, we also differ in how social we are. Ranging from loners to people with 20.000 Facebook friends. There is plenty of variation. Partly because of how we were born, our genes, and partly because of our experiences.
This is true, not only for humans, but for many animal species as well. Individuals of one species can differ in how social they are. But there is one important thing to note here, something which we ‘social’ humans can easily forget, and that is that some species cannot stand each other! Take the giant panda. Males and females live by themselves. They guard their own area and chase out everyone who dares to enter. Even females chase away other females. Only for a short moment a male is allowed, but after he has done his thing, he has to go.
We have also animal species that are part time social, like the blue tit. In spring and summer, when the weather is nice and there is enough food around, these blue tits prefer to keep other birds at a distance. Only a partner is welcome. But in winter, when it is cold and food is difficult to find, they join flocks. Groups of other birds. Together they search for food. If you have a garden and leave some food for the birds in winter, you will probably have seen them.
Finally, there are animals that are social just all the time. Many bat species, for example. They often eat together, sleep together and even take care of their babies together in so-called ‘nurseries’.
So why do we see these differences in social behaviour between and within animal species? And what are the consequences of being social or asocial? These are the kind of questions I try to answer with my research.
Why is this relevant?
Finding the answers to such questions can be important for several reasons. (1) To increase our basic knowledge of nature. For the sake of knowledge itself, but also to inform other scientific fields, such as applied animal science, psychology, behavioural economics and sociology. (2) To help better manage and protect species and (3) to increase the welfare of the animals we live with.
In our homes, we have a variety of pets that also differ in how social they are. Dogs are classic group living animals, just think about the wolves living in packs. Also, rabbits are very social and prefer to be with other rabbits. Cats, however, are actually asocial (not a big surprise). The wild cat lives by itself. Most hamsters also don’t like others around, but certain hamster species, such as the Russian hamster, do like to have a companion from the opposite sex. They form pairs for live and can become depressed when they are not together.
In general, you can say that asocial species which are housed together become stressed. Imagine that you have to spent your whole life living with someone you really dislike. Yet social species, when housed alone, can become fearful and depressed. For dogs, humans can become their companions, but for most other animals this doesn’t work like that. When it comes to animals in captivity it is thus important to know whether they are social, live in pairs or are asocial.
Tracking the social live of a small songbird
In my studies, I focus on animals in the wild. How are their social lives structured and what benefits does it bring them? Since I was a little girl I have been fascinated with how and why animals behave the way they do. So it was not difficult for me to decide what I wanted to become: a biologist. I studied biology and did a PhD studying the daily social behaviour of a songbird: the great tit, a small bird you can often find in your garden and in the forest.
But how do you study a bird that is hiding in the trees most of the time? I did this by putting small transmitters on their back (Figure 2). In this way, I could track where the birds were going and who was meeting whom. More than 150 receivers (small boxes with an antenna) recorded where the birds were going in the forest.
I was especially interested in knowing whether the social behaviour of the birds was related to their personality. Because also animals have personality, they differ in how they handle new or risky situations. Something that is well established now in science. If you have had several pets you will probably have noticed that one is not like the other. This is also true for wild animals.
So, basically, I wanted to know if bold birds were more social than shy birds. Bold birds are birds that take more risks and approach novel object quicker than shy birds. We tested the personality traits of wild birds in the lab before we spatially tracked them in the wild.
Are bold birds more social? This would make sense, right? Also in humans, bolder individuals usually seem the most popular. To answer this question, I analysed the spatial tracking data to find out who was hanging out with whom. In this way, I could construct a social network. A sort of Facebook for birds. And what did I find? Bolder birds (Bigger dots in Figure 3), were more central in the network, they spent relatively the most time close to other birds. While shy birds (Smaller dots in Figure 3), were on the edge of the network. They spent less time with other birds .
Playback experiments with songbirds
Still, being popular (i.e. having many social connections), like having 10000 Twitter followers, does not necessarily mean that you are also a more social individual. Even Donald Trump has more than 30 million twitter followers.
Being more ‘popular’ could be caused by other factors than being social. For example, these birds could be hanging out on spots that happen to attract a lot of other birds, like places where there is plenty of food. Also, other birds might be socially attracted to bolder individuals without these popular birds actively socializing themselves. So, Donald Trump has over 30 million followers on Twitter, but can anyone guess how many people he follows himself? Last time I checked: 45, including his own family, his business, his golf course and his campaign team. A little side note just to illustrate that you don’t have to be a social individual to be popular.
Thus, to find out if bolder birds are actually actively approaching other birds. I performed two different experiments
The first experiment involved pretending to be another bird. So how do you pretend to be another songbird…? By singing! Via a speaker I broadcasted the song of an unfamiliar great tit in the territory of another great tit, which goes a bit like this and I observed how the bird responded. Such an experiment is called a playback experiment. As expected, the bolder birds tried to get really close to the speaker, which they thought was another bird, while the shyer birds kept more of a distance .
However, this behaviour is of course also not really ‘social’. It is aggressive. Bolder birds are more aggressive than shy birds. Maybe also not a big surprise when you think of humans.
Thus secondly, I designed another test in which the birds got to meet an unfamiliar great tit, but without this great tit posing a threat. I did this by showing the birds a High Definition life-size video of a great tit in a neutral lab environment (Figure 4). This kind of experiment is called a video playback experiment. It maybe sounds a bit strange, but the birds respond to this as if there is another bird in the room. Here the birds could choose if they wanted to approach the video great tit or rather stay near a video showing an empty cage. Both videos were played on screens in a small cage so that the birds could not look behind the screen and see that there was not an actual bird there. Surprisingly, in this test, bolder birds did not spent more time with another great tit. Actually, if anything, the shy birds showed more social attraction. They spent most time near the video great tit .
What have I learned from my PhD studies? (1) Individuals of the same species can differ in their personality traits and the time they spent close to others and (2) being bold and popular does not per definition make you a social individual.
If you are interested in finding out more about my studies and animal behaviour in general, please follow me on Twitter. And, unlike Trump, I will follow you back.
Snijders, L.et al. (2014) Social networking in territorial great tits: slow explorers have the least central social network positions.Animal Behaviour98: 95-102.
[2} Snijders, L. et al. (2015) Dawn song predicts behaviour during territory conflicts in personality-typed great tits. Animal Behaviour109: 45-52.
 Snijders, L.et al. (2017) Dominance rank and boldness predict social attraction in great tits. Behavioral Ecology28: 398-406.
“On Sunday 4th June 2017 between 2 and 5 pm, Berlin will host its very first soapbox science event in Tempelhofer feld. Female scientists will step on their soapboxes and tell you about the fascinating work they do, so come join us and add a little extra excitement to your Sunday stroll!”
From 2 to 3 pm I will be talking about the exciting science of animal social behaviour. Join me and my fellow female scientists at Tempelhofer feld!
March 2017, I will start as a postdoc with the Leibniz Institute of Freshwater Ecology and Inland Fisheries, also known as IGB-Berlin. Supported by a 12-month IGB-fellowship, I will study the social network dynamics of guppies, both in the wild (Trinidad!) and in the lab.
I will keep you up to date with my experiences and findings in the field (and the lab) via my website. As a teaser, some pictures from last year’s field work in this beautiful country:
Want to know a bit more about the institute I will spend the next 12 months?
The Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) is a creative, lively and diverse place for conducting research and teaching. Scientists from a whole range of disciplines work under one roof at our Berlin and Neuglobsow sites. Hydrologists, chemists, physicists, microbiologists, limnologists, fish ecologists and fisheries biologists from all over the world investigate the fundamental processes governing rivers, lakes and wetlands, and join forces to develop measures conductive to sustainable water management. In the process, we think beyond individual disciplines and spatial boundaries. After all, it will only be possible to develop solutions to the major challenges of the future by taking an integrative research approach.