behavioural ecology group website phd postdoc projects
PHD & POSTDOC

PROJECTS

Jacopo Di Clemente

Foraging, movements and communication of elusive rorqual whales under anthropogenic pressure

Distinct cetacean populations of the same species living in different oceans may be exposed to different sources and/or levels of exogenous disturbance but have to meet the same endogenous needs such as foraging.

The mouths of filter-feeding cetaceans, such as rorquals (Balaenopteridae), are not built to depredate human fishing gear. As a result, human fishing activities are for them at best neutral, and at worst a severe threat due to potential injuries and noise pollution. In contrast, although deep diving odontocetes hunting with echolocation seem to be more directly and negatively impacted by anthropogenic noise, some populations have learned to take advantage of interactions with fishing activities by eating fish captured by humans.

In both scenarios, there is currently a lack of research quantifying whether prey field and anthropogenic disturbance affect the foraging behaviour of these animals and, as a result, also their foraging kinematics and energetics. Using a combination of non-invasive state-of-the-art technologies and modelling, this project aims to discover if foraging energetics and efficiency in both typical feeding and depredation events change when exposed to different levels of stress in different environments.

Jacopo Di Clemente Foraging movements and communication of elusive rorqual whales under anthropogenic pressure

Credits: Jacopo Di Clemente

Bing Xie Vocal communication in social networks the case of the plains zebra Equus quagga

Credits: Delbars via Getty Images Pro

Bing Xie

Vocal communication in social networks: the case of the plains zebra (Equus quagga)

Living in groups results in various conflicts due to the different needs of each individuals­. In order to maintain group cohesion, group-living animals thus need to synchronize and coordinate activities. A notable way to achieve this aim is through auditory signals, which, because of their loudness, conspicuousness and long-range travelling abilities, can be perceived by more than one individual. Though acoustic communication between one signaler and one receiver has been widely studied (e.g. individual recognition, mother-infant interactions), in social groups, communication occurs in a network composed of many potential signalers and receivers. We are interested in filling current knowledge gaps by studying a yet poorly investigated topic: the relationship between vocal communication and social networks. The project will use the plains zebra as model, for its unique and stable multilevel societies, frequent and multi-meaning calls, migration habits and naturally individually-labeled stripes allowing individual identification. We will test the hypothesis that vocal communication signals facilitate group/herd movement in general and fission-fusion events (when herds split in smaller harems and bachelor groups, and later associate again) in plains zebra. The project will be carried out both in zoos in Denmark and in the wild (Pilanesberg National Park. South Africa). While zoo settings will allow us to perform controlled recordings under limited acoustic interference, recordings in the wild will provide a clearer, more natural picture of the contexts of production of zebra’s calls.

Funding: China Scholarship Council, Carlsberg Research Infrastructure

Romain Lefèvre

Horse vocal communication: investigating the function of biphonation

Vocalisations constitute an efficient and rapid means of transmitting information to conspecifics. Such information can be encoded in the sequence of elements composing an utterance, or in the acoustic structure of the vocalisation itself (i.e. duration, frequency, amplitude). To be transmitted efficiently, pieces of information that can vary independently from each other (e.g. information about the emotion and identity of the caller) should be encrypted in different and non-correlated acoustic features (“segregation of information”). Biphonation, i.e. the presence of two independent fundamental frequencies (lowest frequency of a periodic waveform), constitutes one ideal way to achieve such segregation. A good example of this phenomenon has recently been demonstrated in horses, which produce whinnies made of two fundamental frequencies, a rare phenomenon among mammals. Interestingly, the lowest frequency (“F0”) of whinnies encodes the arousal (intensity) of the emotion experienced by the caller, while the highest frequency (“G0”), encodes the emotional valence (positive vs negative). In this project, we propose to explore the implication of these two frequencies for horse communication.

Funding: Swiss National Science Foundation

Romain Lefevre Horse vocal communication investigating the function of biphonation

Credits: alexeys via Getty Images Pro

Isabel Driscoll Encoding of affective state in meerkat vocalisations

Credits: Isabel Driscoll

Isabel Driscoll

Encoding of affective state in meerkat vocalisations 

Animals’ production of vocalisations varies between being solely dependent on arousal, to referring to a specific object or event in their environment, and in the case of meerkats a combination of both. Meerkat alarm calls are thought to encode predator type (referential) and level of urgency (arousal). We are currently working on whether these calls are truly referential and how much of a role affective state plays on their production. We are doing this by investigating how alarm call production and structure are influenced by an individual’s affective state, and also how this variation may affect the response of the receiver.

Funding: Swiss National Science Foundation, NCCR Evolving Language

Damaris Riedner

Kinship and its impact on mate choice, vocalization and behaviour in southern white rhinoceros

Southern white rhinoceros are in severe need of conservation management to secure their long-term survival. The main threats this charismatic herbivore is facing are poaching and habitat fragmentation, resulting in small and isolated populations. Consequently, the risk of inbreeding increases, which will impact the already low genetic variability of this species. Kin discrimination is one way to avoid the costs of inbreeding. By applying genetic methods, bioacoustics and network analysis, we aim to improve our sparse knowledge of mate choice and kin recognition in white rhinoceros.

damaris riedner kinship and its impact on mate choice vocalization and behaviour in southern white rhinoceros

Credits: Bing Xie

karina stampe communication emotion and defamation in an eupsittula parakeet

Credits: Gustavo_Asciutti from Getty Images

Karina Stampe

Communication, emotion and defamation in an eupsittula parakeet

The existence of complex social systems might have driven the evolution of advanced communication and cognitive abilities, as individuals need to memorise past interactions and many individuals’ identities. However, how these memories are formed and shape social relationships in animals is poorly known. In birds, vocal communication is of utmost importance no matter if the species lives in big social groups or is solitary. The aim of this study is to investigate how vocal information affects the behaviour not only of one individual but of entire groups. Using Eupsittula parakeets, we will study the impact of vocalisations on emotions, pairwise relationships, and how this affects group movement dynamics as a result.

Funding: The Carlsberg Foundation

Malene Friis Hansen

The Long-Tailed Macaque Project

A conservation collaboration seeking to influence long-tailed macaque conservation and welfare through scientific evidence using population census surveys, trade investigation and human-macaque interface evaluation.

Funding: Animal Protection Denmark; long-tailed macaque habitat country research is partially funded by local NGOs and Research Councils

malene friis hansen the long tailed macaque project

Credits: Malene Friis Hansen

Social structure of giraffes effect of social and physical environment

Credits: 12019–12919 via Pixabay

COLLECTIVE PROJECT

Social structure of giraffes: effect of social and physical environment

Recent studies have shown that wild giraffes (Giraffa camelopardis) form non-random associations with each other. In this project we use social network analysis (SNA) to investigate how such associations may be controlled or driven by factors like sex, age, kinship and season. The long-term study takes place in Pilanesberg National Park (PNP), South Africa, in collaboration with Copenhagen Zoo, which offers accommodation in a newly established field laboratory. PNP has a population of about 200 giraffes most of which have been individually identified based on their distinctive coat pattern on both sides of their bodies. A photo archive of the individuals has been constructed and Copenhagen Zoo has started up sampling biopsies from the identified individuals to investigate the relatedness between them. The first results using SNA confirm that giraffes form non-random associations and show that they maintain a stable overall social structure over at least 3½ years and between seasons. This applies to the whole population and to each sex separately, although there are sexual differences in how seasons may affect the social coherence.