Isabelle Charrier

French National Centre for Scientific Research | CNRS · Paris Saclay Institute of Neuroscience

The Mediterranean monk seal Monachus monachus is one of the most endangered pinnipeds in the world, and is classified as “Endangered” by the International Union for the Conservation of Nature. Any additional knowledge about the species is invaluable to its effective conservation. In the present study, we deployed an autonomous underwater recorder i...

Mother-young vocal recognition is widespread in mammals. The features of vocal recognition are known to be shaped by the ecological constraints faced by each species. In some species, a rapid establishment of mother-young vocal recognition is crucial for offspring's survival. However, knowledge of the precise features of this recognition system, es...

Vocalisations play a vital role in animal communication, as they are involved in many biological functions such as mate selection, individual recognition and care of young. Seabirds often breed in large and dense colonies, making successful recognition between mates or between parents and offspring crucial for reproductive success. Acoustic signals...

Humpback whales ( Megaptera novaeangliae ) use vocalizations during diverse social interactions or activities such as foraging or mating. Unlike songs produced only by males, social calls are produced by all types of individuals (adult males and females, juveniles and calves). Several studies have described social calls in the humpback whale’s bree...

The rapid increase in seaborn trade since the 1990s has resulted in an increase in vessel-derived noise pollution, yet there is little evidence linking these activities to a decline in many marine taxa, such as seabirds. Algoa Bay, South Africa, is a marine biodiversity hotspot, providing habitats for the largest populations of endangered African P...

Communication is the process by which one emitter conveys information to one or several receivers to induce a response (behavioral or physiological) by the receiver. Communication plays a major role in various biological functions and may involve signals and cues from different sensory modalities. Traditionally, investigations of animal communicati...

The Cape fur seal (Arctocephalus pusillus pusillus) is one of the most colonial mammal species in the world. Females exclusively nurse their pups for 9 to 11 months, during which they alternate frequent foraging trips at sea with suckling periods ashore. The survival of the pup thus depends on the ability of the mother–pup pair to relocate each oth...

The increase of anthropogenic noise in the environment is a global phenomenon occurring in various types of habitats. Its impact on wildlife is therefore a growing research concern for many taxa. Due to their amphibious lifestyle, pinnipeds are exposed to anthropogenic noise in both aquatic and terrestrial environments. Using playback experiments,...

For humpback whales, the mother–calf pair is the only stable social unit with calves following their mother after birth and staying in close proximity. This following strategy ensures the maintenance of such close proximity between the mother and her calf, with calves benefiting from maternal protection and care. Using multi-sensor tags, we recorde...

Communication plays a fundamental role in the social behavior of phocids, as individuals gain valuable information that aids in kin recognition, mate selection, and rival assessment. In this chapter, we provide an overview of the communication strategies used by phocid seals, which include acoustic, olfactory, and visual elements. We discuss the so...

Getting maternal milk through nursing is vital for all newborn mammals. Despite its importance, nursing has been poorly documented in humpback whales (Megaptera novaeangliae). Nursing is difficult to observe underwater without disturbing the whales and is usually impossible to observe from a ship. We attempted to observe nursing from the calf's per...

Morphometric studies of humpback whales (Megaptera novaeangliae) occurring in the Indian Ocean area have been limited by the technology currently available. In the Sainte Marie channel, Madagascar, straightforward aerial single-camera photogrammetry was tested on mother-calf pairs that combines standard Unoccupied Aerial Vehicle (UAV) with free, ea...

The cape fur seal is one of the most colonial mammal species in the world. Breeding colonies are composed of harems held by mature males (older than 10 years) with up to 30 females and their pups, while roaming subadult males (younger and socially immature) are kept away from bulls’ territories. As in other pinnipeds, cape fur seals are highly voca...

Vocalisations play a vital role in animal communication, as they are involved in many biological functions. Seabirds often breed in large and dense colonies, making successful recognition between mates or between parents-and offspring crucial for reproductive success. Most seabird species, including Cape gannets (Morus capensis), are monomorphic an...

Bonding between mothers and their young is fundamental to mammalian reproductive behaviour and individual fitness. In social systems where the risk of confusing filial and non-filial offspring is high, mothers should demonstrate early, strong and consistent responses to their kin throughout the period of offspring dependence, irrespective of matern...

The ability to discriminate between familiar and unfamiliar calls may play a key role in pinnipeds' communication and survival, as in the case of mother-pup interactions. Vocal discrimination abilities have been suggested to be more developed in pinniped species with the highest selective pressure such as the otariids; yet, in some groupliving phoc...

Communication is fundamental for the survival of animal species as signals are involved in many social interactions (mate selection, parental care, collective behaviours). The acoustic channel is an important modality used by birds and mammals to reliably exchange information among individuals. In group-living species, the propagation of vocal sign...

Background Studies on animal behaviour often involve the quantification of the occurrence and duration of various activities. When direct observations are challenging (e.g., at night, in a burrow, at sea), animal-borne devices can be used to remotely record the movement and behaviour of an animal (e.g., changing body posture and movement, geographi...

The ability to recognize the identity of conspecifics is a key component for survival of many animal species and is fundamental to social interactions such as parental care, intra-sexual competition or mate recognition. In group-living species, the simultaneous co-existence of many individuals increases the number of interactions and reinforces the...

Otariids and Odobenids produce copious vocal signals in air and/or under water. The two main behavioral contexts in which they produce vocalizations are during mother-young interactions and male breeding vocal behavior. The social bond between mother and her young is very strong in both otariids and walrus, and their vocal exchanges start at birth....

While vocal communication is prominent in pinnipeds, visual and olfactory cues are also important in social interactions, yet they have been poorly investigated. Behavioral observations of mother-pup and male-male interactions suggest the involvement of visual and olfactory cues to facilitate mother-pup reunion and to advertise the presence of comp...

Pinnipeds, as any mammal species, use multimodal signals, including olfactory ones, to ensure vital functions. Thus, some pinniped species seem able to use olfaction in both social and foraging contexts and to discriminate between different odors in air including both natural and artificial odors, but studies on that topic remain scarce. Here, we s...

Dominance hierarchies structure the adult social networks of many mammals. To identify the conditions that support the establishment of stable hierarchical relationships within groups of familiar rivals, we explored the ontogeny of spatial, social and communicative behaviour among male northern elephant seals, Mirounga angustirostris. We demonstrat...

In many species, parents and offspring have developed the ability to vocally identify each other. In avian species, a strong relationship between individual recognition system and social structure has been shown, with recognition systems being more elaborated in species exposed to strong selective pressures (e.g., colonial species vs. solitary spec...

Courtship displays are typically comprised of the same behavioral pattern, or patterns, repeated several times by males. Both the quantity and quality of the displays produced by a given male bird are not, however, constant. The number and/or quality of displays can decrease over time, indicating fatigue, or males can increase the number and/or qua...

Seabirds are highly vocal on land where acoustic communication plays a crucial role in reproduction. Yet, seabirds spend most of their life at sea. They have developed a number of morphological, physiological and behavioural adaptations to forage in the marine environment. The use of acoustic signals at sea could potentially enhance seabirds' forag...

No PDF available ABSTRACT To identify the conditions that support the development of hierarchical relationships within networks of familiar competitive rivals, we consider the ontogeny of area use, social relationships, and communicative behavior among male northern elephant seals (Mirounga angustirostris). We cross-sectionally sampled the behavior...

Olfaction is one of the most commonly used senses for communication among animals and is of particular importance to mother-offspring recognition in mammals. The use of smell in offspring recognition has been well studied, however, we often lack information about the underlying mechanistic basis for olfactory recognition. Using gas chromatography–m...

Seabirds spend most of their time at sea, yet our knowledge of their activities and behaviour is limited due to difficulties of in‐situ data collection. In particular, we know virtually nothing about their acoustic communication when at sea. We benefited from the recent development of miniaturised audio‐recording devices to deployacoustic recorders...

Recognition of individuals or classes of individuals plays an important role in the communication systems of many mammals. The ability of otariid (i.e., fur seal and sea lion) females to locate and identify their offspring in colonies after returning from regular foraging trips is essential to successful pup rearing. It has been shown that olfactio...

Animals often employ multiple sensory modalities for communication and recognition; however, the combination of sensory cues used by individuals in given contexts will vary. Although mother-offspring recognition has been widely investigated and is known to be a multimodal process in gregarious mammal species, there is a dearth of information about...

Spatial proximity to mothers is a key factor in offspring survival in group-living mammals. In humpback whales (Megaptera novaeangliae), an extreme migrating species, new-born calves stay close to their mothers. This proximity can be modified by the presence of other congeners or other species. The spatial relationship between mother and calf can t...

Mammals use multiple sensory cues for mother-offspring recognition. While the role of single sensory cues has been well studied, we lack information about how multiple cues produced by mothers are integrated by their offspring. Knowing that Australian sea lion (Neophoca cinerea) pups recognise their mother's calls, we first tested whether visual cu...

Vocal characteristics can vary among and within populations. In species with geographic variation in the structure of vocalizations, individuals may have the ability to discriminate between calls from local and non-local individuals. The ability to distinguish differences in acoustic signals is likely to have a significant influence on the outcome...

Birds use a variety of sounds in their courtship displays, but the majority of behavioural studies have focused on vocalizations. In contrast, little is known about how non-vocal sounds, or sonations, are used, even though many avian species produce them. The ruffed grouse (Bonasa umbellus) is a useful species to examine non-vocal sounds because th...

Parental care is an important factor influencing offspring survival and adult reproductive success in many vertebrates. Parent–offspring recognition ensures care is only directed to filial young, avoiding the costs of misallocated resource transfer. It is essential in colonial mammal species, such as otariids (fur seals and sea lions), in which rep...

Supplemental feeding, whether intentional or accidental, alters wildlife foraging behaviors and may have consequences at the population and ecosystem levels. Wildlife feeding may also cause animals to develop aggressive behaviors toward conspecifics and people. The risks to humans is potentially accrued when the species is a native predator. Food-b...

The evolutionary origin of rhythm perception, a cognitive ability essential to musicality, remains unresolved [1-5]. The ability to perceive and memorize rhythmic sounds is widely shared among humans [6] but seems rare among other mammals [7, 8]. Although the perception of temporal metrical patterns has been found in a few species, this ability has...

The Mediterranean monk seal Monachus monachus is considered Endangered by the IUCN, and is the most endangered pinniped in the world. Increasing our knowledge of this species is crucial in order to further our understanding of its social behaviour, but also to develop new methods to monitor and protect it. In many species, acoustic communication pl...

Multicomponent signals can be formed by the uninterrupted concatenation of multiple call types. One such signal is found in dingoes, Canis familiaris dingo. This stereotyped, multicomponent ‘bark-howl’ vocalisation is formed by the concatenation of a noisy bark segment and a tonal howl segment. Both segments are structurally similar to bark and how...

Dingoes (genus Canis) produce a stereotyped bark-howl vocalisation, which is a unimodal complex signal formed by the concatenation of two call types (a bark and a howl). Bark-howls may function as alarm signals, although there has been no empirical investigation of this vocalisation’s structure or function. We quantified the content and efficacy of...

Describing patterns of connectivity throughout a species range is critical to conservation management. In common with other mammals, pinnipeds typically display male-biased dispersal. Earlier studies using mitochondrial DNA showed that the endangered Australian sea lion (Neophoca cinerea) exhibits extreme matrilineal structure throughout its range....

Signals are shaped through selective pressures impacting their information content (i.e. 'what' is conveyed) and their efficacy (i.e. 'how' is it conveyed). In the case of long-range communication, a signal's structure should both convey information and allow for detection and discrimination despite the effects of environmental variability during p...

Evidence of animal multimodal signalling is widespread and compelling. Dogs' aggressive vocalisations (growls and barks) have been extensively studied, but without any consideration of the simultaneously produced visual displays. In this study we aimed to categorize dogs' bimodal aggressive signals according to the redundant/non-redundant classific...

In otariids, mother's recognition by pups is essential to their survival since females nurse exclusively their own young and can be very aggressive towards non-kin. Antarctic fur seal, Arctocephalus gazella, come ashore to breed and form dense colonies. During the 4-month lactation period, females alternate foraging trips at sea with suckling perio...

Olfaction is a key sense for mammals, and as a result chemical signals are an important means of communication for most mammalian species. It has long been established that most mammals make, distribute, and respond to chemosignals in a range of contexts, including reproduction, parent–offspring interactions, and social relationships (1). However,...

Specialized signals emitted by competing males often convey honest information about fighting ability. It is generally believed that receivers use these signals to directly assess their opponents. Here, we demonstrate an alternative communication strategy used by males in a breeding system where the costs of conflict are extreme. We evaluated the a...

Mother–pup vocal recognition abilities in pinnipeds reflect maternal reproductive strategies. In otariids, mother–pup pairs are frequently separated during lactation, pups are highly mobile at an early stage, and the high densities of colonies increase the risks of confusion between individuals. Accordingly, vocal recognition between mothers and pu...

Pinnipeds have great potential for comparative studies of mother–pup recognition due to the contrasting maternal strategies adopted by otariids and phocids. Typically, otariid mothers perform foraging trips during lactation, leaving their pups in the colony, whereas phocid mothers remain close by their pups during the entire nursing period. Unlike...

Vocalizing by males plays an important role in the reproductive activities of many species. Geographical variation in the characteristics of male vocalization is well studied in birds, but largely unexplored in mammals. This study quantified the extent of geographical variation in male Australian sea lion, Neophoca cinerea, barking calls and examin...

Northern elephant seals (Mirounga angustirostris) have a polygynous breeding system in which adult males establish dominance hierarchies that determine access to females. Acoustic signaling plays an important role in settling fights between males, as stereotyped displays elicit appropriate behavioral responses from individuals without contact durin...

Geographic variation in animal vocalisations, ranging from micro- to macro-variations, has now been widely documented. These dialects can impair communication between separated groups or populations and thus may play a role in speciation processes. Although the existence of geographical variation has been already shown in some pinnipeds species, th...

A study that was conducted to examine the vocal signature of the male northern elephant seal is presented. Northern elephant seals breed annually during the winter months at islands and mainland rookeries along the western coast of the United States and Mexico. These animals maintain a highly polygynous breeding system in which adult males establis...

Directionality is a key feature of vocalizations in birds and can provide insight into vocalizations’ function and propagation. Despite recent interest in birds’ production of nonvocal acoustic signals, little is known about the directionality of these sounds. Here, we examine the directionality of the drumming display of male Ruffed Grouse (Bonasa...

Australian fur seals breed on thirteen islands located in the Bass Strait, Australia. Land access to these islands is restricted, minimising human presence but boat access is still permissible with limitations on approach distances. Thirty-two controlled noise exposure experiments were conducted on breeding Australian fur seals to determine their b...