Mats Amundin

Sound production mechanisms have been studied in two delphinid species - the harbour porpoise, Phocoena phocoena (L.), and the bottlenosed dolphin, Tursiops truncatus (Montagu). It was found that, in both species, the click sound production was coupled to a considerable pressure increase in the bony nares. The maximum pressure recorded in Phocoena was approximately 54kPa and in Tursiops close to 81 kPa; it was equal in time and amplitude in both nares. The nasal plug muscle was found to be active up to 450 ms prior to and during sound production. Sound production without such activity was not seen. The results suggest that an identical mechanism underlies click production in both species, with, pressurized air being the driving force and the nasal plug muscle having some active regulating function. Probes were inserted into the bony nares of three harbour porpoises, Phocoena phocoena, and one bottlenosed dolphin, Tursiops truncatus, in order to record air pressure variations togethe...

The hearing of the bottlenosed dolphins at Kolmrdens Djurpark, Sweden, was examined using a portable auditory evoked potential (AEP) system in order to examine the hearing capabilities of dolphins housed in quiet environments with an emphasis on age-related hearing variation. Audiograms were measured on two dolphins and modulation rate transfer functions (MRTF) were also measured on two animals. A complete audiogram (4–200 kHz) was obtained for the oldest dolphin, a 34 year old female named Vicky. Her audiogram showed no evidence of high-frequency hearing loss. Notwithstanding this finding, her click evoked auditory brainstem response (ABR) revealed a marked increase in interpeak latency that could be indicative of an underlying hearing defect. The audiogram obtained from for the male dolphin, a 24 year old named Pichi (measured from 4–107 kHz), demonstrated profound hearing loss at all frequencies. The measured MRTF results indicated typical odontocete following responses to rates exceeding 1000 Hz.

Habitat heterogeneity is a crucial driver for species distribution across scales. Harbour porpoise Phocoena phocoena basin-wide distribution is linked to prey availability, and small-scale (kilometres to tens of kilometres) differences in distribution are prevalent. However, information on porpoise distribution and foraging-behaviour variations on a micro-scale (~100 m to kilometres) is limited. To monitor harbour porpoise distribution and foraging activity on a micro-scale, we deployed passive acoustic dataloggers, logging porpoise acoustic activity at 6 sites in a small, high porpoise-density area in southern Sweden. Data were collected for almost a year, giving detailed time series on porpoise activity. The time series were analysed using dynamic time warping to compare activity patterns between sites. Large differences were found between sites separated by only a few hundred meters, indicating micro-scale spatial preference. Spectral analysis for temporal cyclicity in activity r...

Franciscana dolphins in Babitonga Bay represent the only population of that critically endangered species which is confined to an estuary. Surrounded by large cities and harbors, that environment presents intense human activities and potential impacts that may threaten the dolphins. Understanding their habitat use and distribution can inform mitigation of such impacts. Here we used acoustic data from sixty fixed passive acoustic monitoring stations, implemented between June and December 2018. The relationship between the occurrence of franciscanas and environmental variables was investigated with generalized additive mixed models. The selected model presented 51% of explained deviance and included “time of day”, “intensity of presence of Guiana dolphins”, “maximum slope”, and “bottom sediment”, among other less statistically significant variables. A daily distribution pattern was identified, with franciscanas remaining in the areas of greatest occurrence especially in the morning an...

A measure proven successful in mitigating harbor porpoise bycatch, is the use of acoustic deterrents, i.e., pingers. However, most pingers are audible to seals. This may lead to seals associating pinger sounds with easily accessible food, leading to increased depredation, damage, and bycatch. In this study we tested if an experimental pinger, emitting sounds over 30 hr ON/OFF cycles, with low frequency components potentially audible to seals only at close distances, would effectively deter harbor porpoises. The porpoise response was measured by logging echolocation clicks, using C‐POD click detectors, moored at different distances from the pinger. In addition, we calculated the theoretical pinger detection range for seals. Results showed that the pinger had a significant negative effect on the porpoise click activity logged at 0 m and 100 m distance but not at 400 m from the pinger. During pinger ON periods, we found no significant increase in echolocation over consecutive days of t...

The ability of dolphins to produce pulse sounds with a bandwidth of up to 150 kHz, has been intensively studied with focus on their sonar capabilities, i.e. the detection, ranging and discrimination of objects of various shapes, textures and material. The sonar pulses have been found to be directional, with a -3db beam width of about 10 degrees in both the vertical and the horizontal plane, and with the beam axis ea. 5 degrees above that of the rostrum. Pulse sounds also frequently occur in social situations (Paper I), but studies of these sounds traditionally have been limited to their audio band, omni-directional components. Hypothesising that social pulse sounds in bottlenose dolphins (Tursiops truncatus) also were directional, early recordings within this study were done across a net barrier, in a narrow channel connecting two pools, to increase the probability to record such sounds with a fixed hydrophone. These recordings confirmed the presence of ultrasonic frequencies in pulse sounds emitted in aggressive interactions, where the interacting animals were oriented face-to-face on either side of the net barrier. There were also indications that they were directional (Paper I). These sounds also had a pronounced energy peak 1 sec), labelled "Machine-gun" sound, occurred frequently in the initial phase of the aggressive interactions. While emitting this sound, the animal kept its rostrum, and possibly the sound beam axis aimed at the agonist, suggesting that it was deliberately used to expose the opponent to powerful broadband pulse sounds, probably to provoke a fight (Paper III).To avoid the restrictions on the behaviour imposed on the dolphins by the net barrier setup, an acoustic tag system was developed (Paper II). The tag was attached to the receiving dolphin instead of the transmitter, and made it possible to study the use of the directionality of the pulse sounds in social contexts, while the interacting dolphins were fully free-swimming. The tag, based on click detectors, recorded the envelope of pulses within two narrow band pass frequency filters, centred on 70kHz and 120kHz, respectively (Paper II). The tag recordings verified the presence of energy within both filter frequency bands in social pulse sounds, in particular in aggressive interactions (Paper III). This thesis suggests that thedirectionality of such pulse sounds is used intentionally to address social signals to a specific individual, or group of individuals. The relatively loud omni-directional audio band component will facilitate for nearby conspecifics to monitor the progress of the interaction. It will also make the signal clearly audible to the opponents throughout an interaction, even if they may be tumbling around, being unable to keep the sound beam axis aimed at the other. Similar pulse bursts were recorded in association with what was interpreted as play-fight, between subadults and juveniles (Paper IV). However, unlike the real aggressive bursts, these bursts had a trailing FM whistle, and this combined signal is suggested to be an appeasement signal, analogous with the laugh and giggle observed in apes. It is supposed to prevent play-fights from escalating into physical and potentially dangerous real fights. It was never recorded in true aggressive interactions among adults.There were individual differences between the animals in amount of received directional pulse sounds while carrying the tag (Paper III). The socially most active of the females, having an intermediate position in the dominance hierarchy, received significantly more directional pulse sounds than the other, socially less active, but higher ranked female. The breeding male received the least number of pulse sounds. This lends support to the presence of "echolocation manners", as suggested by Johnson and Norris (1994), making it socially unacceptable to aiming the sonar beam towards conspecifics unless the intention is to conveying a social message.Dolphins lack the facial plasticity playing a dominant role in the social life of many terrestrial mammals, e.g. primates, canids and felids. This directional signal modality is used to express internal emotions and can be addressed to selected individuals, further stressed by a direct glare. Dolphins completely lack such a facial plasticity but most likely not the need for expressing emotions. This thesis suggests that in dolphins the facial expressions may have been replaced bydirectional pulse sounds. The facial expressions in e.g., wolves, is supposed to be the result of a mixture of dominance/aggression vs. submission/fear emotions. We propose that the pulse sounds, seen in the aggressive interactions, reflect a similar mix of feelings. Obvious parameters in such a graded social signal system are pulse repetition rate, amplitude, duration and power spectrum. To study this further a broadband acoustic tag, preferably attached to several animals simultaneously, is required.

ABSTRACT SAMBAH (Static Acoustic Monitoring of the Baltic Sea Harbor Porpoise) is an EU LIFE + -funded project with the primary goal of estimating the abundance and distribution of the critically endangered Baltic Sea harbor porpoise. From May 2011 to April 2013, project members in all EU countries around the Baltic Sea undertook a static acoustic survey using 304 porpoise detectors distributed in a randomly positioned systematic grid in waters 5–80 m deep. In the recorded data, click trains originating from porpoises have been identified automatically using an algorithm developed specifically for Baltic conditions. To determine the click train C-POD detection function, a series of experiments have been carried out, including acoustic tracking of wild free ranging porpoises using hydrophone arrays in an area with moored C-PODs and playbacks of porpoise-like signals at SAMBAH C-PODs during various hydrological conditions. Porpoise abundance has been estimated by counting the number of individuals detected in short time interval windows (snapshots), and then accounting for false positive detections, probability of animals being silent, and probability of detection of non-silent animals within a specified maximum range. We describe the method in detail, and how the auxiliary experiments have enabled us to estimate the required quantities.

Environmental and ecological factors can trigger changes in the acoustic repertoire of cetaceans. This study documents the first use of a well-established passive acoustic monitoring device (C-POD) to analyze echolocation sounds and behavior of franciscana dolphins in different habitats: estuary [Babitonga Bay (BB)] and open sea [Itapirubá Beach (IB)]. A total of 10 924 click trains were recorded in BB and 6 093 in IB. An inter-click interval < 10 ms (so called "feeding buzzes") was used as a proxy for foraging activity. The main difference in the acoustic parameters between the two habitats was related to the frequency spectrum, with higher maximum and lower modal and minimum click frequencies in BB, and a train frequency range of 17 kHz, against 10 kHz in IB. Also, the click emission rate (clicks/s) was almost 20% higher in BB. Both studied habitats showed a high proportion of feeding buzzes (BB = 68%; IB = 58%), but with a higher probability of occurrence in BB (p < 0.001) and at night (p < 0.001) in both habitats. The C-PODs showed great potential to monitor occurrence, bioacoustics parameters, and echolocation behavior of franciscana dolphins. Longer-term temporal and spatial monitoring are necessary for elucidating several issues raised in this study.

Book AbstractDolphin researchers have collected an impressive amount of data over the last twenty years, thanks to advances in technology for monitoring, recording, and analyzing dolphin behavior as well as increasing interest in exploring and modeling dolphins’ cognitive capacities. This volume offers a comprehensive reference to the latest research on dolphin communication and cognition, reporting on findings from both the laboratory and the field. The contributors review a wide range of topics, including vocalization, abstract reasoning abilities, imitation and learning, social cognition, echolocation, and ethical issues in working with cetaceans.The book begins by examining the dolphin brain and its evolution, the anatomy of its unique sound production and reception systems, and its sensory abilities. It next treats communication, reviewing the complexity of dolphins’ vocalization, and then describes research on cognition, from both experimental and developmental perspectives. F...

Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical ‘‘metallic, blood-like’ ’ odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions w...

The most well-known behaviour of porpoises is their smooth, rolling way of surfacing when they breath. Observations made by Spencer et. al. (1966) on the Killer whale, Orcinus orca, indicates that the respiratory act includes "orienting movements of a dorsal flexure of the thorax, and integrated flipper, fluke and body movements brought together in a complex involuntary act preceding the movement of air". Such movements are seen in beached animals (Spencer et al. 1966), in surface sleeping ones (McGormick 1969), and according to the latter author, the absence of the tail movements are used to indicate depth of anesthesia, being the last movements to disappear before surgical plane is reached. Spencer et. al. (1966) also investigated the duration of a blow (expiration and

Play-fighting is common in many mammals, especially among juveniles/subadults, where it provides a safe opportunity to practice behaviours important to adulthood. To prevent escalation into a potentially dangerous real fight, play fighting is often accompanied by acoustic and/or visual appeasement behaviours. We studied aggressive and play-fight behaviours in bottlenose dolphins (Tursiops truncatus) at the Kolmården Dolphinarium. The results show that

Dolphin sonar has been extensively studied over several decades, and much of its basic characteristics are well known (Au 1993). However, most of these studies have been based on an experimental setup where the dolphin has been trained to be voluntarily fixed, so its directional sonar beam could be recorded with fixed hydrophones. Although this allows for very exact measurements, it most likely has prevented the full dynamic potential of the dolphin’s sonar to be revealed. Also the dolphin’s response to scientific questions, e.g. in target detection threshold or discrimination trials, mostly has been a “go/no go” response or pressing a yes/no paddle. This traditional experimental methodology to measure the response makes rather coarse indications of choice. It is difficult to refine and will be unpractical with a multi-choice paradigm. Therefore a new EchoLocation Visualisation and Interface System (ELVIS) has been developed at Lund University in cooperation with Kolmarden Wild Anim...

Knowing the abundance of a population is a crucial component to assess its conservation status and develop effective conservation plans. For most cetaceans, abundance estimation is difficult given their cryptic and mobile nature, especially when the population is small and has a transnational distribution. In the Baltic Sea, the number of harbour porpoises (Phocoena phocoena) has collapsed since the mid-20th century and the Baltic Proper harbour porpoise is listed as Critically Endangered by the IUCN; however, its abundance remains unknown. Here, one of the largest ever passive acoustic monitoring studies was carried out by eight Baltic Sea nations to estimate the abundance of the Baltic Proper harbour porpoise for the first time. By logging porpoise echolocation signals at 298 stations during May 2011-April 2013, calibrating the loggers’ spatial detection performance at sea, and measuring the click rate of tagged individuals, we estimated an abundance of 66-1,143 individuals (95% C...

Genetic variation is necessary to maintain the ability of wild and domestic populations to genetically adapt to changed selective pressures. When relationships among individuals are known, conservation genetic management can be based on statistical pedigree analysis. Such approaches have traditionally focused on wild animal conservation breeding in captivity. In this thesis, I apply pedigree-based techniques to domestic and wild animal populations, focusing on two canids – the domestic dog and the wild wolf.Main objectives include to 1) develop a means for making any pedigree fit the input requirements of the software Population Management x (PMx) and to use this program to 2) investigate rate of inbreeding and loss of genetic variation in dog breeds, including possible correlations between recent inbreeding and health problems, 3) estimate effects on inbreeding of the 2010 hunt of the endangered Swedish wolf population, and to 4) evaluate the potential to genetically support this w...

Chemosignals are used by predators to localize prey and by prey to avoid predators. These cues vary between species, but the odor of blood seems to be an exception and suggests the presence of an evolutionarily conserved chemosensory cue within the blood odor mixture. A blood odor component, E2D, has been shown to trigger approach responses identical to those triggered by the full blood odor in mammalian carnivores and as such, is a key candidate as a food/alarm cue in blood. Using a multidisciplinary approach, we demonstrate that E2D holds the dual function of affecting both approach and avoidance behavior in a predator-prey predicted manner. E2D evokes approach responses in two taxonomically distant blood-seeking predators, Stable fly and Wolf, while evoking avoidance responses in the prey species Mouse. We extend this by demonstrating that this chemical cue is preserved in humans as well; E2D induces postural avoidance, increases physiological arousal, and enhances visual percept...

... Acoustic Touch Screen for Dolphins, First application of ELVIS - an Echo-Location Visualization and Interface System. ... ELVIS basically consists of a matrix of 16 hydrophones attached to a semi transparent screen lowered into the water of the pool where the dolphins swim freely. ...

Cross-fostering in canids, with captive-bred pups introduced into endangered wild populations, might aid conservation efforts by increasing genetic diversity and lowering the risk of inbreeding depression. The gray wolf (Canis lupus lupus) population in Scandinavia suffers from severe inbreeding due to a narrow genetic base and geographical isolation. This study aimed at evaluating the method to cross-foster wolf pups from zoo-born to zoo-born litters. The following was assessed: female initial acceptance of foster pups, growth rate in relation to age difference between foster pups and pups in recipient litters and survival over the first 33 weeks. The study included four litters added by two foster pups in each. The age differences between the foster pups and the recipient litters were 2-8 days. After augmentation, all four females accepted the foster pups, demonstrated by her moving the entire litter to a new den site. Growth rate was dependent on the age difference of the pups in the foster litters, with a considerably slower growth rate in the 8 days younger pups. However, these pups later appeared to be at no disadvantage. Foster pups had a higher survival rate than females' pups, however, the causes of death were probably not kin or non-kin related. The results indicate that cross-fostering works in gray wolves and that this might be a plausible way to increase genetic variation in the wild population. Zoo Biol. 9999:1-6, 2015. © 2015 Wiley Periodicals, Inc.