Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| target detection, shape discrimination, and signal characteristics of an echolocating false killer whale (pseudorca crassidens). | this study demonstrated the ability of a false killer whale (pseudorca crassidens) to discriminate between two targets and investigated the parameters of the whale's emitted signals for changes related to test conditions. target detection performance comparable to the bottlenose dolphin's (tursiops truncatus) has previously been reported for echolocating false killer whales. no other echolocation capabilities have been reported. a false killer whale, naive to conditioned echolocation tasks, was ... | 1992 | 1401519 |
| underwater audiogram of a false killer whale (pseudorca crassidens). | underwater audiograms are available for only a few odontocete species. a false killer whale (pseudorca crassidens) was trained at sea life park in oahu, hawaii for an underwater hearing test using a go/no-go response paradigm. over a 6-month period, auditory thresholds from 2-115 khz were measured using an up/down staircase psychometric technique. the resulting audiogram showed hearing sensitivities below 64 khz similar to those of belugas (delphinapterus leucas) and atlantic bottlenosed dolphin ... | 1988 | 3183211 |
| mass stranding of odontoceti caused by parasitogenic eighth cranial neuropathy. | hearing organs of the odontoceti from two mass strandings in 1983 and 1986 were examined histopathologically. in the 1983 stranding, two of three pilot whales (globicephala macrorhynchus) were necropsied and numerous nasitrema sp. were found close to the eighth cranial nerve (nervus vistibulo cochlearis) in both animals. patchy degeneration of the eighth cranial nerve in and out of the modiolus of the cochlea was observed. in the 1986 stranding, five of 125 false killer whales (pseudorca crassic ... | 1987 | 3682083 |
| behaviour of the pseudorca crassidens (owen) off the spanish mediterranean coast. | 1967 | 5630198 | |
| echolocation signals and transmission beam pattern of a false killer whale (pseudorca crassidens). | the echolocation transmission beam pattern of a false killer whale (pseudorca crassidens) was measured in the vertical and horizontal planes. a vertical array of seven broadband miniature hydrophones was used to measure the beam pattern in the vertical plane and a horizontal array of the same hydrophones was used in the horizontal plane. the measurements were performed in the open waters of kaneohe bay, oahu, hawaii, while the whale performed a target discrimination task. four types of signals, ... | 1995 | 7608405 |
| a review of heavy metal and organochlorine levels in marine mammals in australia. | study of toxic contaminants in marine mammal specimens collected around australia is currently uncoordinated and piecemeal. most states collect samples but there is little or no financial support for their analysis. this study combines data, published or unpublished, from 13 sources. heavy metals have been analysed in about 676 specimens; over 400 were for mercury levels in p. macrocephalus taken at a whaling station. the remaining samples were mostly from toothed whales, a few baleen whales (< ... | 1994 | 7973602 |
| acoustic effects of the atoc signal (75 hz, 195 db) on dolphins and whales. | the acoustic thermometry of ocean climate (atoc) program of scripps institution of oceanography and the applied physics laboratory, university of washington, will broadcast a low-frequency 75-hz phase modulated acoustic signal over ocean basins in order to study ocean temperatures on a global scale and examine the effects of global warming. one of the major concerns is the possible effect of the atoc signal on marine life, especially on dolphins and whales. in order to address this issue, the he ... | 1997 | 9165743 |
| haematological findings in captive dolphins and whales. | to examine haematological features in five species of healthy, captive marine mammals. | 1997 | 9258426 |
| comparative kinematics and hydrodynamics of odontocete cetaceans: morphological and ecological correlates with swimming performance. | propulsive morphology and swimming performance were compared for the odontocete cetaceans delphinapterus leucas, orcinus orca, pseudorca crassidens and tursiops truncatus. morphological differences were apparent among the whales. the general body contour and low-aspect-ratio caudal flukes of d. leucas indicated that this species was a low-performance swimmer compared with the other species. propulsive motions were video-taped as animals swam steadily in large pools. video tapes were analyzed dig ... | 1998 | 9739069 |
| characterizing the graded structure of false killer whale (pseudorca crassidens) vocalizations. | the vocalizations from two, captive false killer whales (pseudorca crassidens) were analyzed. the structure of the vocalizations was best modeled as lying along a continuum with trains of discrete, exponentially damped sinusoidal pulses at one end and continuous sinusoidal signals at the other end. pulse trains were graded as a function of the interval between pulses where the minimum interval between pulses could be zero milliseconds. the transition from a pulse train with no inter-pulse interv ... | 1998 | 9745747 |
| the neural network classification of false killer whale (pseudorca crassidens) vocalizations. | this study reports the use of unsupervised, self-organizing neural network to categorize the repertoire of false killer whale vocalizations. self-organizing networks are capable of detecting patterns in their input and partitioning those patterns into categories without requiring that the number or types of categories be predefined. the inputs for the neural networks were two-dimensional characterization of false killer whale vocalization, where each vocalization was characterized by a sequence ... | 1998 | 9857520 |
| comparative kinematics and hydrodynamics of odontocete cetaceans: morphological and ecological correlates with swimming performance. | propulsive morphology and swimming performance were compared for the odontocete cetaceans delphinapterus leucas, orcinus orca, pseudorca crassidens and tursiops truncatus. morphological differences were apparent among the whales. the general body contour and low-aspect-ratio caudal flukes of d. leucas indicated that this species was a low-performance swimmer compared with the other species. propulsive motions were video-taped as animals swam steadily in large pools. video tapes were analyzed dig ... | 1998 | 9866875 |
| morphology of the complex laryngeal gland in the atlantic bottlenose dolphin, tursiops truncatus. | a complex lymphoepithelial gland is a constant feature in the larynx of atlantic bottlenose dolphins, tursiops truncatus, based on study of 56 animals. larynges were removed from fresh, non-decomposed beach-stranded animals for gross examination and histological sampling. a large lymphoepithelial gland occurs in the rostro-ventral mucosa of the larynx, overlying the cricoid cartilage. it presents as a well-defined, elevated, and heavily trabeculated area. histological examination reveals a pseud ... | 1999 | 9892423 |
| monitoring of progesterone in captive female false killer whales, pseudorca crassidens. | the present study describes progesterone profiles to enhance understanding of general reproductive patterns in three female captive false killer whales and analyzes potential relationships in progesterone concentrations between plasma, salivary, and ocular secretions. plasma progesterone concentrations reflected ovarian activity for most of the year, with increased concentrations in the spring and summer, indicating that the two adult female false killer whales were spontaneous ovulators and sea ... | 1999 | 10480983 |
| heterogeneity of myoglobin distribution in the locomotory muscles of five cetacean species. | myoglobin is an important storage site for oxygen in the swimming muscles of diving marine mammals. however, little is known about its distribution within muscles since previous studies have relied on single samples. the goal of this study was to determine the distribution of myoglobin within the swimming muscles of five species of cetacean: dusky dolphin, false killer whale, striped dolphin, humpbacked dolphin and bottlenose dolphin. the entire dorsal (epaxial) and ventral (hypaxial) swimming m ... | 2001 | 11136607 |
| mirror image processing in three marine mammal species: killer whales (orcinus orca), false killer whales (pseudorca crassidens) and california sea lions (zalophus californianus). | dolphins (tursiops truncatus) and their relatives might be expected to show mirror-induced contingency checking, a prerequisite to self-recognition, because of their high brain development, their complex social life and their demonstrated abilities in bodily imitation. a study of killer whales'(orcinus orca) behaviour in front of a mirror is presented, including a mark test. shorter investigations of mirror behaviour are also described in false killer whales (pseudorca crassidens) and california ... | 2001 | 11334706 |
| gastrointestinal parasites and prey items from a mass stranding of false killer whales, pseudorca crassidens, in rio grande do sul, southern brazil. | the gastrointestinal tract of 14 false killer whales, 6 males and 8 females, stranded in june 1995 in southern brazil, with total standard lengths from 338 to 507 cm, were analysed for endoparasites and food items. a pregnant female had a male foetus of 77.5 cm. parasites were found in all 14 false killer whales. the nematode anisakis simplex (rudolphi, 1809) was found in the stomach of 57% of the animals and the acanthocephalan bolbosoma capitatum (linstow, 1889) porta, 1908 was present in the ... | 2001 | 11340462 |
| bronchoscopy of cetaceans. | bronchoscopy is a standard diagnostic and therapeutic procedure in respiratory medicine and has been performed on many animal species. cetaceans suffer considerable morbidity and mortality from lower respiratory tract infections, and it is very difficult to sample lower respiratory tract secretions for microbiology and other analyses. we report our experience on performing fiberoptic bronchoscopy in three bottle-nosed dolphins (tursiops truncatus) and one false killer whale (pseudorca crassidens ... | 2002 | 11838223 |
| stenurus globicephalae baylis et daubney, 1925 (nematoda: pseudaliidae) from a false killer whale, pseudorca crassidens (cetacea: delphinidae), stranded on the coast of uruguay. | stenurus globicephalae baylis et daubney, 1925 (nematoda: pseudaliidae) was found in the cranial air sinuses of a false killer whale, pseudorca crassidens (owen), stranded on the coast of uruguay in 1999. although this species has been reported once in p. crassidens from the north atlantic, this is the first record for south america. a total of 920 specimens were obtained, of which 663 were females (body length: 4.34 +/- 0.45 cm) and 257 were males (2.99 +/- 0.18 cm). morphometric details are pr ... | 2002 | 12016448 |
| evidence of helicobacter sp. in dental plaque of captive dolphins (tursiops gephyreus). | gastrointestinal lesions have been extensively reported in wild and captive marine mammals. however, their etiology remains unclear. in humans and other animals, chronic gastritis and peptic ulcers have been associated with helicobacter sp. therefore, the aim of our study was to investigate the presence of helicobacter sp. in the gastric juice, dental plaque, and saliva of marine mammals living in a controlled environment. five dolphins (tursiops gephyreus), one killer whale (orcinus orca), one ... | 2002 | 12238390 |
| echolocation signals of wild atlantic spotted dolphin (stenella frontalis). | an array of four hydrophones arranged in a symmetrical star configuration was used to measure the echolocation signals of the atlantic spotted dolphin (stenella frontalis) in the bahamas. the spacing between the center hydrophone and the other hydrophones was 45.7 cm. a video camera was attached to the array and a video tape recorder was time synchronized with the computer used to digitize the acoustic signals. the echolocation signals had bi-modal frequency spectra with a low-frequency peak bet ... | 2003 | 12558295 |
| evoked potential recording during echolocation in a false killer whale pseudorca crassidens. | 2003 | 12765359 | |
| mercury contamination in the red meat of whales and dolphins marketed for human consumption in japan. | cetacean products sold for human consumption in japan originate from a wide range of whale, dolphin, and porpoise species caught off several areas of the japan coast, antarctic and north pacific oceans. we surveyed the total mercury (t-hg) levels in red meat, the most popular cetacean products in japan. we also analyzed the dna of these to obtain information regarding species. according to the genetic analysis, the red meats originating from nine species of odontocete and six species of mystecet ... | 2003 | 12854705 |
| an analysis in mass osteology of the false killer whale, pseudorca crassidens (owen). | 1956 | 13378811 | |
| strouhal numbers and optimization of swimming by odontocete cetaceans. | swimming efficiencies of fish and cetaceans have been related to a certain synchrony between stroke cycle frequency, peak-to-peak tail/fluke amplitude and mean swimming speed. these kinematic parameters form a non-dimensional wake parameter, referred to as a strouhal number, which for the range between 0.20 and 0.40 has been associated with enhanced swimming efficiency for fish and cetaceans. yet to date there has been no direct experimental substantiation of what strouhal numbers are preferred ... | 2004 | 15073196 |
| echolocation clicks of two free-ranging, oceanic delphinids with different food preferences: false killer whales pseudorca crassidens and risso's dolphins grampus griseus. | toothed whales (odontoceti, cetacea) navigate and locate prey by means of active echolocation. studies on captive animals have accumulated a large body of knowledge concerning the production, reception and processing of sound in odontocete biosonars, but there is little information about the properties and use of biosonar clicks of free-ranging animals in offshore habitats. this study presents the first source parameter estimates of biosonar clicks from two free-ranging oceanic delphinids, the o ... | 2004 | 15107437 |
| the interaction of outgoing echolocation pulses and echoes in the false killer whale's auditory system: evoked-potential study. | brain auditory evoked potentials (aep) associated with echolocation were recorded in a false killer whale pseudorca crassidens trained to accept suction-cup eeg electrodes and to detect targets by echolocation. aep collection was triggered by echolocation pulses transmitted by the animal. the target was a hollow aluminum cylinder of strength of -22 db at a distance from 1 to 8 m. each aep record was obtained by averaging more than 1000 individual records. all the records contained two aep sets: ... | 2004 | 15237846 |
| invariance of evoked-potential echo-responses to target strength and distance in an echolocating false killer whale. | brain auditory evoked potentials (aeps) were recorded in a false killer whale pseudorca crassidens trained to accept suction-cup eeg electrodes and to detect targets by echolocation. aep collection was triggered by echolocation pulses transmitted by the animal. the target strength varied from -22 to -40 db; the distance varied from 1.5 to 6 m. all the records contained two aep sets: the first one of a constant latency (transmission-related aep) and a second one with a delay proportional to the d ... | 2005 | 16018494 |
| total mercury, methyl mercury, and selenium levels in the red meat of small cetaceans sold for human consumption in japan. | we surveyed the total mercury (t-hg) and methyl mercury (m-hg) levels in red meat products (n = 160) from small cetacean species sold for human consumption in markets throughout japan from 2000 to 2003. genetic identification showed that the red meat products originated from nine species: false killer whale, bottlenose dolphin, short-finned pilot whale, striped dolphin, rough-toothed dolphin, risso's dolphin, pantropical spotted dolphin, baird's beaked whale, and dall's porpoise. t-hg and m-hg c ... | 2005 | 16124305 |
| behavioral and auditory evoked potential audiograms of a false killer whale (pseudorca crassidens). | behavioral and auditory evoked potential (aep) audiograms of a false killer whale were measured using the same subject and experimental conditions. the objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. behavioral audiograms used 3-s pure-tone stimuli from 4 to 45 khz, and were conducted with a go/no-go modified staircase procedure. aep audiograms used 20-ms sinusoidally amplitude-modulated tone bursts from 4 ... | 2005 | 16266188 |
| source-to-sensation level ratio of transmitted biosonar pulses in an echolocating false killer whale. | transmitted biosonar pulses, and the brain auditory evoked potentials (aeps) associated with those pulses, were synchronously recorded in a false killer whale pseudorca crassidens trained to accept suction-cup eeg electrodes and to detect targets by echolocation. aep amplitude was investigated as a function of the transmitted biosonar pulse source level. for that, a few thousand of the individual aep records were sorted according to the spontaneously varied amplitude of synchronously recorded bi ... | 2006 | 16875248 |
| two new species of symbiotic ciliates from the respiratory tract of cetaceans with establishment of the new genus planilamina n. gen. (dysteriida, kyaroikeidae). | examination of mucus discharged from the blowhole of atlantic bottlenose dolphin (tursiops truncatus) at marine life oceanarium, gulfport, mississippi, and false killer whale (pseudorca crassidens) and atlantic bottlenose dolphin at seaworld orlando, orlando, florida, using live observations and protargol impregnation revealed mixed infections of kyaroikeus cetarius and two new species. planilamina n. gen. is characterized by a c-shaped argentophilic band located along the laterally flattened ma ... | 2006 | 17123404 |
| accumulation of organotin compounds in tissues and organs of stranded whales along the coasts of thailand. | concentrations of butyltin (bt) and phenyltin (pt) compounds were measured in organs and tissues of five species of whales (bride's whale [balaenoptera edeni], false killer whale [pseudorca crassidens], pygmy sperm whale [kogia breviceps], short-finned pilot whale [globicephala macrorhynchus], and sperm whale [physeter macrocephalus]) found stranded on the coasts of thailand. the mean concentrations of bts in various whales were in the range of 0.157 to 1.03 mg kg(-1 )wet weight, which were high ... | 2007 | 17285238 |
| evoked-potential recovery during double click stimulation in a whale: a possibility of biosonar automatic gain control. | false killer whale pseudorca crassidens auditory brainstem responses (abr) were recorded using a double-click stimulation paradigm specifically measuring the recovery of the second response (to the test click) as a function of the inter-click interval (ici) at various levels of the conditioning and test click. at all click intensities, the slopes of recovery functions were almost constant: 0.6-0.8 microv per ici decade. therefore, even when the conditioning-to-test-click level ratio was kept con ... | 2007 | 17297815 |
| contamination level of mercury in red meat products from cetaceans available from south korea markets. | levels of total mercury (t-hg) were surveyed in red meat (n=73) and liver (n=3) from toothed whales, dolphins and porpoises (odontocetes) sold for human consumption in the coastal cities of south korea. high concentrations of t-hg were found in the liver products of finless porpoises (18.7 and 156 microg/wet g) and common dolphins (13.2 microg/wet g). the t-hg concentrations in red meat products were highest in the false killer whale (9.66+/-12.3 microg/wet g, n=9), bottlenose dolphin (10.6+/-12 ... | 2007 | 17395215 |
| the perception of complex tones by a false killer whale (pseudorca crassidens). | complex tonal whistles are frequently produced by some odontocete species. however, no experimental evidence exists regarding the detection of complex tones or the discrimination of harmonic frequencies by a marine mammal. the objectives of this investigation were to examine the ability of a false killer whale to discriminate pure tones from complex tones and to determine the minimum intensity level of a harmonic tone required for the whale to make the discrimination. the study was conducted wit ... | 2007 | 17407913 |
| a tool for real-time acoustic species identification of delphinid whistles. | the ability to identify delphinid vocalizations to species in real-time would be an asset during shipboard surveys. an automated system, real-time odontocete call classification algorithm (rocca), is being developed to allow real-time acoustic species identification in the field. this matlab-based tool automatically extracts ten variables (beginning, end, minimum and maximum frequencies, duration, slope of the beginning and end sweep, number of inflection points, number of steps, and presence/ab ... | 2007 | 17614515 |
| hearing sensitivity during target presence and absence while a whale echolocates. | hearing sensitivity was measured in a false killer whale during echolocation. sensitivity was measured using probe stimuli as sinusoidally amplitude modulated signals with a 22.5-khz carrier frequency and recording auditory evoked potentials as envelope-following responses. the probes were presented and responses were recorded during short 2-s periods when the animal echolocated to detect the presence or absence of a target in a go/no-go paradigm. in the target-absent trials, a hearing threshold ... | 2008 | 18177180 |
| a false killer whale adjusts its hearing when it echolocates. | the use of auditory evoked potential (aep) measurements has added considerably to knowledge of the hearing mechanisms of marine mammals. we have recently measured the hearing of a stranded infant risso's dolphin, the audiograms of white-beaked dolphins temporarily caught and released, and the hearing of anaesthetized polar bears. most small toothed whales echolocate and hear very high frequency sounds underwater. while much has previously been learned about the echolocation performance and chara ... | 2008 | 18490386 |
| comparative genomic analysis of the whale (pseudorca crassidens) prnp locus. | there have been many studies of the morphology, behavioral audiograms, and population structure of the false killer whale (pseudorca crassidens), but sequencing, mapping, and functional and comparative genomics studies are still largely unknown. in this paper, we sequenced three novel bac clones corresponding to a total length of 308 kb and spanning the prnp, prnd, and rassf2 loci, and conducted comparative genomic analysis to examine the genomic structure of the false killer whale prnp locus. w ... | 2008 | 18521124 |
| histological, immunohistochemical and pathological features of the pituitary gland of odontocete cetaceans from the western gulf of mexico. | pituitary glands were recovered from dolphins and small whales found stranded along the texas coast of the gulf of mexico over a 15-year period (1991-2006). one hundred animals of 14 species were found to be suitable for inclusion in this study. of these, 72 were atlantic bottlenose dolphins (tursiops truncatus). other species included were the melon-headed whale (peponocephala electra), spinner dolphin (stenella longirostris), striped dolphin (stenella coeruleoalba), pantropical spotted dolphin ... | 2008 | 18621384 |
| forward masking as a mechanism of automatic gain control in odontocete biosonar: a psychophysical study. | in a false killer whale pseudorca crassidens, echo perception thresholds were measured using a go/no-go psychophysical paradigm and one-up-one-down staircase procedure. computer controlled echoes were electronically synthesized pulses that were played back through a transducer and triggered by whale emitted biosonar pulses. the echo amplitudes were proportional to biosonar pulse amplitudes; echo levels were specified in terms of the attenuation of the echo sound pressure level near the animal's ... | 2008 | 18647006 |
| sequence analysis of dolphin ferritin h and l subunits and possible iron-dependent translational control of dolphin ferritin gene. | iron-storage protein, ferritin plays a central role in iron metabolism. ferritin has dual function to store iron and segregate iron for protection of iron-catalyzed reactive oxygen species. tissue ferritin is composed of two kinds of subunits (h: heavy chain or heart-type subunit; l: light chain or liver-type subunit). ferritin gene expression is controlled at translational level in iron-dependent manner or at transcriptional level in iron-independent manner. however, sequencing analysis of mari ... | 2008 | 18954429 |
| large-scale microfabricated channel plates for high-throughput, fully automated dna sequencing. | we have described a new dna sequencing platform based on the sanger chemistry, in which the large-scale microfabricated channel plates and electrophoretic system result in higher-throughput dna sequencing. three hundred and eighty-four channels are arranged in a fan-like shape on a 25x47 cm glass plate, on which 384 oval sample holes are connected to each channel coupled to the opposite anode access holes. two microfabricated plates are set on the sequencing apparatus, in which sequencing electr ... | 2008 | 19016243 |
| comment on "comparative genomic analysis of the whale (pseudorca crassidens) prnp locus". | a reminder that another paper on the cetacean prnp locus has been published before kim et al.'s paper (2008. genome, 51: 452-464) is presented along with a consideration of the related results. | 2008 | 19088820 |
| forward-masking based gain control in odontocete biosonar: an evoked-potential study. | auditory evoked potentials (aeps) were recorded during echolocation in a false killer whale pseudorca crassidens. an electronically synthesized and played-back ("phantom") echo was used. each electronic echo was triggered by an emitted biosonar pulse. the echo had a spectrum similar to that of the emitted biosonar clicks, and its intensity was proportional to that of the emitted click. the attenuation of the echo relative to the emitted click and its delay was controlled by the experimenter. fou ... | 2009 | 19354417 |
| evolutionary characterization of a highly repetitive sequence identified from the false killer whale (pseudorca crassidens). | we report here that a novel 1,869 bp repetitive sequence identified from the false killer whale (pseudorca crassidens) could be a new molecular phylogenetic marker in cetaceans. results of pcr amplification and southern blot hybridization using 16 species' genomic dnas from five different families revealed that the repetitive sequence is highly conserved within all delphinidae species. notably, specific primers designed for this repetitive sequence effectively amplified the targeted repetitive u ... | 2009 | 19556712 |
| high levels of persistent organic pollutants measured in blubber of island-associated false killer whales (pseudorca crassidens) around the main hawaiian islands. | 2009 | 19782380 | |
| sound production by singing humpback whales. | sounds from humpback whale songs were analyzed to evaluate possible mechanisms of sound production. song sounds fell along a continuum with trains of discrete pulses at one end and continuous tonal signals at the other. this graded vocal repertoire is comparable to that seen in false killer whales [murray et al. (1998). j. acoust. soc. am. 104, 1679-1688] and human singers, indicating that all three species generate sounds by varying the tension of pneumatically driven, vibrating membranes. patt ... | 2010 | 20370048 |
| target distance-dependent variation of hearing sensitivity during echolocation in a false killer whale. | evidence of varying hearing sensitivity according to the target distance was obtained in a false killer whale pseudorca crassidens during echolocation. auditory evoked potentials (aeps) triggered by echolocation clicks were recorded. the target distance varied from 1 to 6 m. the records contained aeps to the self-heard emitted click and aeps to the echoes. mean level of echolocation clicks depended on distance (the longer the distance, the higher the click level), however, the effect of click le ... | 2010 | 20550281 |
| comparative genomic analysis of the false killer whale (pseudorca crassidens) lmbr1 locus. | the sequencing and comparative genomic analysis of lmbr1 loci in mammals or other species, including human, would be very important in understanding evolutionary genetic changes underlying the evolution of limb development. in this regard, comparative genomic annotation of the false killer whale lmbr1 locus could shed new light on the evolution of limb development. we sequenced two false killer whale bac clones, corresponding to 156 kb and 144 kb, respectively, harboring the tightly linked rnf32 ... | 2010 | 20924415 |
| decreased echolocation performance following high-frequency hearing loss in the false killer whale (pseudorca crassidens). | toothed whales and dolphins possess a hypertrophied auditory system that allows for the production and hearing of ultrasonic signals. although the fossil record provides information on the evolution of the auditory structures found in extant odontocetes, it cannot provide information on the evolutionary pressures leading to the hypertrophied auditory system. investigating the effect of hearing loss may provide evidence for the reason for the development of high-frequency hearing in echolocating ... | 2010 | 20952621 |
| change in echolocation signals with hearing loss in a false killer whale (pseudorca crassidens). | the echolocation signals of a false killer whale (pseudorca crassidens) were collected during a wall thickness discrimination task and compared to clicks recorded during an identical experiment in 1992. during the sixteen year time period, the subject demonstrated a loss of high frequency hearing of about 70 khz. clicks between the two experiments were compared to investigate the effect of hearing loss on echolocation signals. there was a significant reduction in the peak frequency, center frequ ... | 2010 | 20968393 |
| characteristic metabolism of free amino acids in cetacean plasma: cluster analysis and comparison with mice. | from an evolutionary perspective, the ancestors of cetaceans first lived in terrestrial environments prior to adapting to aquatic environments. whereas anatomical and morphological adaptations to aquatic environments have been well studied, few studies have focused on physiological changes. we focused on plasma amino acid concentrations (aminograms) since they show distinct patterns under various physiological conditions. plasma and urine aminograms were obtained from bottlenose dolphins, pacifi ... | 2010 | 21072195 |
| molecular identification of novel alpha- and gammaherpesviruses from cetaceans stranded on japanese coasts. | herpesviral infections have been documented in some cetaceans; however, they have not yet been identified in species in the western north pacific. in the present study, 178 tissue samples from 76 stranded cetacean individuals were tested for the presence of herpesviruses. herpesvirus genomic dna fragments surrounding the dna polymerase gene were amplified in samples from four individuals. ta cloning and direct sequencing of these dna fragments revealed the presence of two novel alphaherpesviruse ... | 2011 | 21303205 |
| novel gastric helicobacters and oral campylobacters are present in captive and wild cetaceans. | the mammalian gastric and oral mucosa may be colonized by mixed helicobacter and campylobacter species, respectively, in individual animals. to better characterize the presence and distribution of helicobacter and campylobacter among marine mammals, we used pcr and 16s rdna sequence analysis to examine gastric and oral samples from ten dolphins (tursiops gephyreus), one killer whale (orcinus orca), one false killer whale (pseudorca crassidens), and three wild la plata river dolphins (pontoporia ... | 2011 | 21592686 |
| historical and current records of aquarium cetaceans in china. | the number of cetaceans housed in aquariums in china is increasing. detailed information on the historical and current population status has not been reported, despite its importance for successful breeding and population management. questionnaires were conducted between december 2006 and may 2009, and the information was used to construct studbooks. our survey showed that 10 species had been introduced to aquariums since 1978, including 26 (with 15 in the current population) finless porpoises ( ... | 2011 | 21674602 |
| dental pathology in dolphins (cetacea: delphinidae) from the southern coast of brazil. | pathological processes observed in the stomatognathic systems of mammalian species are a useful source of information about the habits, evolution and general health of such animals. studies of pathological conditions on teeth are common in humans and other primates, but rare in wild animals in general and marine mammals in particular. for cetaceans, previous studies provided scanty records of dental anomalies in a few species. this is the first broad and systematic inventory of dental pathology ... | 2011 | 21790069 |
| interaction of emitted sonar pulses and simulated echoes in a false killer whale: an evoked-potential study. | auditory evoked potentials (aep) were recorded during echolocation in a false killer whale pseudorca crassidens. an electronically synthesized and played-back (simulated) echo was triggered by an emitted biosonar pulse, and its intensity was proportional to that of the emitted click. the delay and transfer factor of the echo relative to the emitted click was controlled by the operator. the echo delay varied from 2 to 16 ms (by two-fold steps), and the transfer factor varied within ranges from -4 ... | 2011 | 21895108 |
| similarities in echolocation strategy and click characteristics between a pseudorca crassidens and a tursiops truncatus. | a previous comparative analysis of normalized click amplitude spectra from a tursiops truncatus has shown that those frequencies with the lowest click-to-click variability in spectral content were the frequencies the animal paid attention to during target discrimination tasks. in that case, the dolphin only paid attention to the frequency range between 29-42 khz which had a significantly higher degree of consistency in spectral content than frequencies above 42 khz. here it is shown that despite ... | 2011 | 22087936 |
| deep granulomatous dermatitis of the fin caused by fusarium solani in a false killer whale (pseudorca crassidens). | a 10-year-old female false killer whale (pseudorca crassidens) developed skin lesions in the left breast fin. histopathologically, the lesions consisted of multiple granulomas spread diffusely into the deep dermis and bone; characteristically, each granuloma has septate, branching fungal hyphae and chlamydospores surrounded by eosinophilic splendore-hoeppli materials. macrophages, epithelioid cells and multinucleated giant cells in the granulomas reacted mainly to anti-sra-e5 antibody against hu ... | 2011 | 22214860 |
| single-lobed frequency-dependent beam shape in an echolocating false killer whale (pseudorca crassidens). | recent studies indicate some odontocetes may produce echolocation beams with a dual-lobed vertical structure. the shape of the odontocete echolocation beam was further investigated in a false killer whale performing an echolocation discrimination task. clicks were recorded with an array of 16 hydrophones and frequency-dependent amplitude plots were constructed to assess beam shape. the majority of the echolocation clicks were single-lobed in structure with most energy located between 20 and 80 k ... | 2012 | 22280619 |
| active echolocation beam focusing in the false killer whale, pseudorca crassidens. | the odontocete sound production system is highly complex and produces intense, directional signals that are thought to be focused by the melon and the air sacs. because odontocete echolocation signals are variable and the emitted click frequency greatly affects the echolocation beam shape, investigations of beam focusing must account for frequency-related beam changes. in this study we tested whether the echolocation beam of a false killer whale changed depending on target difficulty and distanc ... | 2012 | 22442368 |
| organochlorine compound accumulation in delphinids from rio de janeiro state, southeastern brazilian coast. | the present study investigated organochlorine compound levels (pcbs, ddts and hcb) in blubber samples of six delphinid species from rio de janeiro state, southeastern brazilian coast. the species analyzed inhabit the continental shelf (one killer whale, one false killer whale, two bottlenose dolphins, three rough-toothed dolphins, and four long-beaked common dolphins) and open ocean (four fraser's dolphins). pcbs represented the greatest proportion of the sum of all measured organochlorines (fro ... | 2012 | 22771469 |
| spatial orientation of different frequencies within the echolocation beam of a tursiops truncatus and pseudorca crassidens. | a two-dimensional array of 16 hydrophones was created to map the spatial distribution of different frequencies within the echolocation beam of a tursiops truncatus and a pseudorca crassidens. it was previously shown that both the tursiops and pseudorca only paid attention to frequencies between 29 and 42 khz while echolocating. both individuals tightly focused the 30 khz frequency and the spatial location of the focus was consistently pointed toward the target. at 50 khz the beam was less focuse ... | 2012 | 22894240 |
| dental wear in dolphins (cetacea: delphinidae) from southern brazil. | (1) dental wear is a common phenomenon in mammals. its occurrence is influenced by tooth anatomy, animal physiology, biomechanics and behaviour. so far, investigations of dental wear in cetaceans have been scanty and superficial. we compare the frequencies of occurrence, location and intensity of dental wear in some species of dolphins from southern brazil, south atlantic ocean. (2) teeth of ten species were evaluated using a stereoscopic microscope to identify wear facets, which were classified ... | 2013 | 22939372 |
| a whale better adjusts the biosonar to ordered rather than to random changes in the echo parameters. | a false killer whale's (pseudorca crassidens) sonar clicks and auditory evoked potentials (aeps) were recorded during echolocation with simulated echoes in two series of experiments. in the first, both the echo delay and transfer factor (which is the db-ratio of the echo sound-pressure level to emitted pulse source level) were varied randomly from trial to trial until enough data were collected (random presentation). in the second, a combination of the echo delay and transfer factor was kept con ... | 2012 | 22978908 |
| a false killer whale reduces its hearing sensitivity when a loud sound is preceded by a warning. | we investigated the possibility of conditioned dampening of whale hearing thresholds when a loud sound is preceded by a warning sound. the loud sound was a tone of 20 khz, 170 db re. 1 μpa, 5 s. hearing sensitivity was measured using pip-train test stimuli and auditory evoked potential recording. the same test-sound stimuli served as warning sounds. the durations of the warning sounds were varied randomly to avoid locking an anticipated conditioning effect to the timing immediately before the lo ... | 2013 | 23619406 |
| high accumulation of pcdd, pcdf, and pcb congeners in marine mammals from brazil: a serious pcb problem. | blubber samples from three delphinid species (false killer whale, guiana and rough-toothed dolphin), as well as liver samples from franciscana dolphins were analyzed for dioxins and related compounds (drcs). samples were collected from 35 cetaceans stranded or incidentally captured in a highly industrialized and urbanized area (southeast and southern brazilian regions). dioxin-like pcbs accounted for over 83% of the total teq for all cetaceans. non-ortho coplanar pcbs, for franciscanas (82%), an ... | 2013 | 23827355 |
| nasal sound production in echolocating delphinids (tursiops truncatus and pseudorca crassidens) is dynamic, but unilateral: clicking on the right side and whistling on the left side. | toothed whales produce sound in their nasal complex by pneumatic actuation of phonic lip pairs within the blowhole. it has been hypothesized that dual actuation of the phonic lip pairs can generate two pulses that merge to form a single echolocation click with a higher source level, broader bandwidth and larger potential for beam steering than if produced by a single pair of phonic lips. here, we test that hypothesis by measuring the sound production of five echolocating delphinids using hydroph ... | 2013 | 24133152 |
| trophic relationships and habitat preferences of delphinids from the southeastern brazilian coast determined by carbon and nitrogen stable isotope composition. | to investigate the foraging habitats of delphinids in southeastern brazil, we analyzed stable carbon (δ(13)c) and nitrogen (δ(15)n) isotopes in muscle samples of the following 10 delphinid species: sotalia guianensis, stenella frontalis, tursiops truncatus, steno bredanensis, pseudorca crassidens, delphinus sp., lagenodelphis hosei, stenella attenuata, stenella longirostris and grampus griseus. we also compared the δ(13)c and δ(15)n values among four populations of s. guianensis. variation in ca ... | 2013 | 24358155 |
| prevalence of external injuries in small cetaceans in aruban waters, southern caribbean. | aruba, located close to the coasts of colombia and venezuela, is one of the most densely populated islands in the caribbean and supports a wide range of marine-related socio-economic activities. however, little is known about the impacts of human activities on the marine environment. injuries in marine mammals can be used to examine interactions with human activities and identify potential threats to the survival of populations. the prevalence of external injuries and tooth rake marks were exami ... | 2014 | 24586473 |
| accounting for subgroup structure in line-transect abundance estimates of false killer whales (pseudorca crassidens) in hawaiian waters. | for biological populations that form aggregations (or clusters) of individuals, cluster size is an important parameter in line-transect abundance estimation and should be accurately measured. cluster size in cetaceans has traditionally been represented as the total number of individuals in a group, but group size may be underestimated if group members are spatially diffuse. groups of false killer whales (pseudorca crassidens) can comprise numerous subgroups that are dispersed over tens of kilome ... | 2014 | 24587372 |
| 200 khz commercial sonar systems generate lower frequency side lobes audible to some marine mammals. | the spectral properties of pulses transmitted by three commercially available 200 khz echo sounders were measured to assess the possibility that marine mammals might hear sound energy below the center (carrier) frequency that may be generated by transmitting short rectangular pulses. all three sounders were found to generate sound at frequencies below the center frequency and within the hearing range of some marine mammals, e.g. killer whales, false killer whales, beluga whales, atlantic bottlen ... | 2014 | 24736608 |
| nuclear and mitochondrial patterns of population structure in north pacific false killer whales (pseudorca crassidens). | false killer whales (pseudorca crassidens) are large delphinids typically found in deep water far offshore. however, in the hawaiian archipelago, there are 2 resident island-associated populations of false killer whales, one in the waters around the main hawaiian islands (mhi) and one in the waters around the northwestern hawaiian islands (nwhi). we use mitochondrial dna (mtdna) control region sequences and genotypes from 16 nuclear dna (nucdna) microsatellite loci from 206 individuals to examin ... | 2014 | 24831238 |
| conditioned hearing sensitivity reduction in a bottlenose dolphin (tursiops truncatus). | the conditioned change in hearing sensitivity during a warning sound preceding a loud sound was investigated in the bottlenose dolphin. hearing sensitivity was measured using pip-train test stimuli and auditory evoked potential recording. when the test/warning stimulus with a frequency of 22.5 or 32 khz preceded the loud sound with a frequency of 22.5 khz and a sound pressure level of 165 db re. 1 μpa rms, hearing thresholds before the loud sound increased relative to the baseline. the threshold ... | 2014 | 24855674 |
| multiple populations of pantropical spotted dolphins in hawaiian waters. | understanding gene flow and dispersal patterns is important for predicting effects of natural events and anthropogenic activities on animal populations. in hawaii, most species of odontocetes are managed as single populations. recent exceptions include false killer whales, spinner dolphins, and common bottlenose dolphins, for which studies have shown fidelity to individual islands or groups of islands. our study focused on pantropical spotted dolphins. we analyzed mitochondrial control region an ... | 2014 | 25124812 |
| cytochrome p4501a1 expression in blubber biopsies of endangered false killer whales (pseudorca crassidens) and nine other odontocete species from hawai'i. | odontocetes (toothed whales) are considered sentinel species in the marine environment because of their high trophic position, long life spans, and blubber that accumulates lipophilic contaminants. cytochrome p4501a1 (cyp1a1) is a biomarker of exposure and molecular effects of certain persistent organic pollutants. immunohistochemistry was used to visualize cyp1a1 expression in blubber biopsies collected by non-lethal sampling methods from 10 species of free-ranging hawaiian odontocetes: short-f ... | 2014 | 25134676 |
| buzzing during biosonar-based interception of prey in the delphinids tursiops truncatus and pseudorca crassidens. | echolocating bats and toothed whales probe their environment with ultrasonic sound pulses, using returning echoes to navigate and find prey in a process that appears to have resulted from a remarkable convergence of the two taxa. here, we report the first detailed quantification of echolocation behaviour during prey capture in the most studied delphinid species, a false killer whale and a bottlenose dolphin. using acoustic dtags, we demonstrate that just prior to prey interception these delphini ... | 2014 | 25394631 |
| acoustic detection of biosonar activity of deep diving odontocetes at josephine seamount high seas marine protected area. | the temporal occurrence of deep diving cetaceans in the josephine seamount high seas marine protected area (jshsmpa), south-west portugal, was monitored using a passive acoustic recorder. the recorder was deployed on 13 may 2010 at a depth of 814 m during the north atlantic treaty organization centre for maritime research and experimentation cruise "sirena10" and recovered on 6 june 2010. the recorder was programmed to record 40 s of data every 2 min. acoustic data analysis, for the detection an ... | 2015 | 25994682 |
| linking the occurrence of cutaneous opportunistic fungal invaders with elemental concentrations in false killer whale (pseudorca crassidens) skin. | cetaceans, occupying the top levels in marine food chains, are vulnerable to elevated levels of potentially toxic trace elements, such as aluminium (al), mercury (hg) and nickel (ni). negative effects associated with these toxic metals include infection by opportunistic microbial invaders. to corroborate the link between the presence of cutaneous fungal invaders and trace element levels, skin samples from 40 stranded false killer whales (fkws) were analysed using culture techniques and inductive ... | 2015 | 26034019 |
| support for the beam focusing hypothesis in the false killer whale. | the odontocete sound production system is complex and composed of tissues, air sacs and a fatty melon. previous studies suggested that the emitted sonar beam might be actively focused, narrowing depending on target distance. in this study, we further tested this beam focusing hypothesis in a false killer whale. using three linear arrays of hydrophones, we recorded the same emitted click at 2, 4 and 7 m distance and calculated the beamwidth, intensity, center frequency and bandwidth as recorded o ... | 2015 | 26056247 |
| trace element concentrations in liver of 16 species of cetaceans stranded on pacific islands from 1997 through 2013. | the impacts of anthropogenic contaminants on marine ecosystems are a concern worldwide. anthropogenic activities can enrich trace elements in marine biota to concentrations that may negatively impact organism health. exposure to elevated concentrations of trace elements is considered a contributing factor in marine mammal population declines. hawai'i is an increasingly important geographic location for global monitoring, yet trace element concentrations have not been quantified in hawaiian cetac ... | 2016 | 26283019 |
| hearing sensation changes when a warning predicts a loud sound in the false killer whale (pseudorca crassidens). | stranded whales and dolphins have sometimes been associated with loud anthropogenic sounds. echolocating whales produce very loud sounds themselves and have developed the ability to protect their hearing from their own signals. a false killer whale's hearing sensitivity was measured when a faint warning sound was given just before the presentation of an increase in intensity to 170 db. if the warning occurred within 1-9 s, as opposed to 20-40 s, the whale showed a 13-db reduction in hearing sens ... | 2016 | 26611027 |
| learning and extinction of conditioned hearing sensation change in the beluga whale (delphinapterus leucas). | ice-dwelling beluga whales are increasingly being exposed to anthropogenic loud sounds. beluga's hearing sensitivity measured during a warning sound just preceding a loud sound was tested using pip-train stimuli and auditory evoked potential recording. when the test/warning stimulus with a frequency of 32 or 45 khz preceded the loud sound with a frequency of 32 khz and a sound pressure level of 153 db re 1 μpa, 2 s, hearing thresholds before the loud sound increased relative to the baseline. the ... | 2016 | 26659822 |
| transmission beam characteristics of a risso's dolphin (grampus griseus). | the echolocation system of the risso's dolphin (grampus griseus) remains poorly studied compared to other odontocete species. in this study, echolocation signals were recorded from a stationary risso's dolphin with an array of 16 hydrophones and the two-dimensional beam shape was explored using frequency-dependent amplitude plots. click source parameters were similar to those already described for this species. centroid frequency of click signals increased with increasing sound pressure level, w ... | 2016 | 26827004 |
| using line acceleration to measure false killer whale (pseudorca crassidens) click and whistle source levels during pelagic longline depredation. | false killer whales (pseudorca crassidens) depredate pelagic longlines in offshore hawaiian waters. on january 28, 2015 a depredation event was recorded 14 m from an integrated gopro camera, hydrophone, and accelerometer, revealing that false killer whales depredate bait and generate clicks and whistles under good visibility conditions. the act of plucking bait off a hook generated a distinctive 15 hz line vibration. two similar line vibrations detected at earlier times permitted the animal's ra ... | 2016 | 27908079 |
| evidence for a postreproductive phase in female false killer whales pseudorca crassidens. | a substantial period of life after reproduction ends, known as postreproductive lifespan (prls), is at odds with classical life history theory and its causes and mechanisms have puzzled evolutionary biologists for decades. prolonged prls has been confirmed in only two non-human mammals, both odontocete cetaceans in the family delphinidae. we investigate the evidence for prls in a third species, the false killer whale, pseudorca crassidens, using a quantitative measure of prls and morphological e ... | 2017 | 28649267 |