Tadamichi Morisaka

Tadamichi Morisaka
Mie University · Graduate School of Bioresources

Dr

About

54
Publications
35,216
Reads
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881
Citations
Citations since 2016
20 Research Items
534 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Additional affiliations
October 2013 - April 2016
Tokai University
Position
  • Lecturer
December 2010 - September 2013
Kyoto University
Position
  • Professor (Assistant)

Publications

Publications (54)
Article
Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island are important both commercially (swim-with-dolphin programs) and scientifically (long-term underwater behavioral studies). However, this population experienced a substantial population decline (31% of identified dolphins) between 2008 and 2011, which prompted us to monitor pop...
Article
Full-text available
Toothed whales are the ideal model to validate the hypothesis that the complexity of sound communication relates to sociality. Compared to the numerous studies on several toothed whale species with complex social systems, there are very few studies on sound communication in species with simple social systems, such as narrow-ridged finless porpoises...
Article
We report the first case of conspecific calf-directed aggression in Pacific white-sided dolphins (Lagenorhynchus obliquidens) as a possible infanticide attempt in Mutsu Bay, Japan. Our observation of a 75-minute-long persistent attack on a neonate was performed by 10 attackers (4 adult males, 1 possible male, and 5 of unknown sex) and left the neon...
Article
Yawning is an involuntary action that occurs in three phases: (1) slow mouth opening accompanied by inhalation, (2) maintaining the maximum mouth size, and (3) quick closure with exhalation. Yawning is a phylogenetically widespread behavior in vertebrates. Here, we report yawn-like behavior in a captive dugong. Fourteen yawn-like behaviors were ide...
Article
Fins are among the most important morphological appendages of aquatic animals. Although sall cetaceans have flippers and dorsal fins with a variety of morphologies and postures, the diversity and function of the fins have not attracted much attention thus far. In this study, we recorded the behaviour of five captive species of small cetaceans, incl...
Article
Yawning is an involuntary action that begins with a slow opening of the mouth with inhalation, followed by a maximum gaping phase, and ends with a short exhalation and the closing of the mouth. A wide variety of vertebrate species, including humans, yawn. Here, we report underwater yawn-like behavior in three captive common bottlenose dolphins, inf...
Article
This study aimed to assess the prey species and foraging behaviour of Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island, a small oceanic island ~200 km south of Tokyo, Japan, using underwater observations and stomach content analysis of eight individuals to determine the feeding ecology of this population. Our results suggest...
Article
Full-text available
In riverine ‘soundscapes’, complex interactions between sound, substrate type, and depth create difficulties in assessing impacts of anthropogenic noise pollution on freshwater fauna. Underwater noise from vessels can negatively affect endangered Ganges river dolphins (Platanista gangetica), which are ‘almost blind’ and rely entirely on high-freque...
Chapter
The behavioral ecology of Tursiops aduncus (Indo-Pacific bottlenose dolphin) is usually reviewed alongside the much more widely studied T. truncatus (common bottlenose dolphin). However, the smaller, typically shallow water T. aduncus has been closely scrutinized in Australian and Japanese waters. As a result, there now exists a robust body of info...
Article
Pacific white-sided dolphins are a group-living species and appear to exchange “contact calls” to maintain group cohesion. The aim of this study was to find and characterize their contact calls. Calls were recorded from two females at Osaka Aquarium KAIYUKAN (OAK) and three females at Izu-Mito Sea Paradise (IMSP). Because they often produced pulsed...
Article
Previous studies have suggested that belugas (Delphinapterus leucas) use pulsed calls both with and without tone-like components for contact calls. However, call classification differs among researchers, and the definition of contact calls remains ambiguous. The objective of this study is to organize and integrate this information to redefine the c...
Article
• Limited visual perception in aquatic environments has driven the evolution of diverse sensory modalities in aquatic mammals. Dolphins largely use echolocation for prey capture in the face of limited visual and olfactory cues. Multiple foraging modes exist, although an understanding of how sensory systems are adapted to environmental and prey char...
Article
Emigration of individual animals is an important biological phenomenon that depends on both populations and ecosystem attributes. Off Mikura Island, a long-term identification survey of individual Indo-Pacific bottlenose dolphins has been conducted since 1994 using an underwater video system. Between 1994 and 2014, 277 individual dolphins were iden...
Article
Full-text available
The finless porpoise has characteristic tubercles on its dorsal ridge. These tubercles are supposed to have biological and mechanical functions. In the former, specific nerve endings and fibers exist in the tubercles indicating its function as a sensory organ. In the latter, tubercles provide fluid dynamic functions such as underwater drag reductio...
Article
Fluid dynamic effects between adjacent streamline bodies have a conspicuous role in drag reduction. One typical example is a dolphin drafting. When two dolphins such as a mother and a calf swim side by side, the calf seldom flaps its tail fin, indicating the calf utilizes the fluid dynamic force between the two bodies as a thrust. This force is gen...
Article
Full-text available
Alloparental behaviour and adoption have been reported in many mammals and birds. Such behaviours are energetically costly, and their causes and functions remain unclear. We observed the adoption behaviour of a wild Indo-Pacific bottlenose dolphin (Tursiops aduncus) near Mikura Island, Japan. A calf was seen with its mother on six observation days....
Article
This paper shows how simple, non-invasive measurement method is important for conserving large animals living underwater. We have studied freeranging wild Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island, Japan for about 15 years. We usually observe dolphin behavior and record acoustics underwater including photo-identificat...
Article
Full-text available
Introduction: Species with fission-fusion social systems tend to exchange individualized contact calls to maintain group cohesion. Signature whistles by bottlenose dolphins are unique compared to the contact calls of other non-human animals in that they include identity information independent of voice cues. Further, dolphins copy the signatures o...
Article
Full-text available
Post-conflict affiliation between former opponents or between one of the former opponents and bystanders might have the function of conflict management, which reduces the costs associated with aggressions. One of the suggested functions of post-conflict affiliation is decreased renewed aggressions directed from aggressors to victims. However, the e...
Article
Full-text available
Knowledge for the distribution pattern of an animal species is fundamental for our understanding and conservation of the animal. Since researchers cannot conduct visual surveys during night, the nighttime distribution pattern of the dolphins which can hunt prey in a dark condition is difficult to study. Here we describe the detection of the nightti...
Article
Belugas often exchange one type of broadband pulsed sounds (termed PS1 calls) which possibly functions as a contact calls (Morisaka et al., 2013). Here we investigate how belugas embed their signature information into the PS1 calls. PS1 calls were recorded from each of five belugas including both sexes and various ages at the Port of Nagoya Public...
Article
Full-text available
Several terrestrial animals and delphinids manipulate objects in a tactile manner, using parts of their bodies, such as their mouths or hands. In this paper, we report that bottlenose dolphins (Tursiops truncatus) manipulate objects not by direct bodily contact, but by spontaneous water flow. Three of four dolphins at Suma Aqualife Park performed o...
Article
Full-text available
Common bottlenose dolphins (Tursiops truncatus) use individually distinctive signature whistles which are highly stereotyped and function as contact calls. Here we investigate whether Indo-Pacific bottlenose dolphins (T. aduncus) use signature whistles. The frequency trace of whistle contours recorded from three genetically distinct free-ranging po...
Article
This paper proposes a novel method for contact-free measurement of an object's length with non-rigid deformation using a 3D Bézier curve. This technique is developed to measure body size of the free-ranging wild dolphins without touching them. Body size is the most basic and important information to measure the health condition of an animal populat...
Article
Full-text available
Mother–calf interactions and the behaviors of mothers during separation from their calves were examined in four Commerson’s dolphin (Cephalorhynchus commersonii) mother–calf pairs. Four infants were observed: 56.8 h over 30 days from birth to 263 days of age, 36.9 h over 20 days from birth to 149 days of age, 10.4 h over 3 days from birth to 2 days...
Article
Full-text available
Spontaneous ejaculation, which is defined as the release of seminal fluids without apparent sexual stimulation, has been documented in boreoeutherian mammals. Here we report spontaneous ejaculation in a wild Indo-Pacific bottlenose dolphin (Tursiops aduncus), and present a video of this rare behavior. This is the first report of spontaneous ejacula...
Data
Spontaneous ejaculation by a wild Indo-Pacific bottlenose dolphin ( Tursiops aduncus ) off Mikura Island. (MP4)
Article
Full-text available
Belugas (Delphinapterus leucas) produce echolocation clicks, burst pulses, and whistles. The sounds of 3 captive belugas were recorded using 2 hydrophones at the Port of Nagoya Public Aquarium. There were stable individual differences in the pulse patterning of one type of pulsed sounds (PS1 call), suggesting that belugas use these as “signature” c...
Article
Full-text available
The evolutional pathway of communication sounds (i.e., whistles) in odontocetes is reviewed using recent acoustic and phylogenetic studies. The common ancestor of Ziphiidae, Inioidea, and Delphinoidea acquired the ability to whistle in the early Oligocene. Subsequently, Pontoporiidae, Phocoenidae, and the genus Cephalorhynchus lost the ability to w...
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The observed reactions of dolphins indicate that this tagging approach has negligible impacts on the dolphin behaviour and Heaviside's dolphins might be tagged with suction cup tags without adverse affects.
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Field recordings of echolocation signals produced by Heaviside's dolphins (Cephalorhynchus heavisidii) were made off the coast of South Africa using a hydrophone array system. The system consisted of three hydrophones and an A-tag (miniature stereo acoustic data-logger). The mean centroid frequency was 125 kHz, with a -3 dB bandwidth of 15 kHz and...
Article
Full-text available
Recent technological advances have allowed researchers to acquire a vast amount of information on wild cetaceans, much of which had previously been inaccessible. However, despite these new technologies, existing studies on cetaceans in captivity remain valuable. In this article, we review the recent research conducted on captive cetaceans in Japan...
Article
Bottlenose dolphins live in social groups characterized by long-term relationships between individuals. Previous studies have reported a variety of aggressive behaviors such as chasing, head-butting, biting, etc. in both captive and wild dolphins. An affiliative body contact among dolphins may repair deteriorated relationships or reduce tension wit...
Article
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We quantitatively analysed synchronous breathing for dyads in Indo-Pacific bottlenose dolphins at Mikura Island, Tokyo, Japan. For most cases, we observed dyads swimming in the same direction (97%), in close proximity (i.e., less than 1.5m) and with their body axes parallel as they breathed synchronously. Moreover, the pairs engaged in identical be...
Article
Dolphins live in aquatic environments that differ greatly from our terrestrial environments. Several studies have demonstrated that dolphins have complex cognitive abilities comparable to those of great apes. No comparative cognitive studies of dolphins were conducted in Japan until the mid-1990s, but several pioneering works on dolphin comparative...
Article
Full-text available
Male Bengalese Finches Lonchura striata var. domestica sing syntactically complex songs. A previous study suggested that complex songs elicit more reproductive behavior in female Bengalese Finches than do simple songs. Since the study measured passive reactions to stimulus songs, it is not clear if female birds actively choose complex songs. Here w...
Article
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Twelve Bengalese finches (Lonchura striata var. domestica) were trained to discriminate between a conspecific and a heterospecific song in a go/no-go operant task. Training the birds to go for the conspecifics song or to go for the heterospecific song required the same number of training sessions. Nine possible cognitive tactics could be used to so...
Article
A disparate selection of toothed whales (Odontoceti) share striking features of their acoustic repertoires including the absence of whistles and high frequency but weak (low peak-to-peak source level) clicks that have a relatively long duration and a narrow bandwidth. The non-whistling, high frequency click species include members of the family Pho...
Article
Full-text available
Cetaceans, including whales, dolphins, and porpoises, are mammals that live in aquatic environments far different from those of our terrestrial world. Recent studies have revealed that cetaceans have complex societies and cognitive abilities, comparable to those of “rational” terrestrial animals such as apes and humans. The positive correlation bet...
Article
Bottlenose dolphins exhibit complex social affiliations that may be shaped by interactions among individuals. Affiliative body contact among dolphins may repair deteriorated relationships or reduce tension within the group following aggressive interactions. We investigated the time-series association between one type of contact behavior (flipper-ru...
Article
Full-text available
Bottlenose dolphins (Tursiops truncatus) commu- nicate using various acoustic signals, including whistles and pulsed sounds. Many studies have been conducted on dolphin whistle development over a long span, but little research has been done on sounds produced by neonatal dolphins just after birth. For this reason, we studied the acoustic characteri...
Article
Full-text available
Neonatal bottlenose dolphins (Tursiops trunca- tus) produce many sounds just after birth, includ- ing whistles and pulsed sounds. Herein, we report the possible function of the sounds produced by two captive-born, neonatal bottlenose dolphin as revealed by behavioural observations. Typical sucking sounds were observed during 71 to 81% of all suckli...
Article
Whistles of Indo-Pacific bottlenose dolphins from three populations in Japan were collected and analyzed quantitatively. Geographic variations in the whistles among populations were found. Significant differences in the whistles among years within each population were also found, but those differences could not explain whole differences among popul...
Article
Communication among animals should use signals that are most efficient in their particular habitat. Here, we report data from 3 populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Japan that produce whistles transmitted efficiently through environmental ambient noise. We compared the characteristics of the ambient noise in the dol...
Article
Full-text available
Communication among animals should use signals that are most efficient in their particular habitat. Here, we report data from 3 populations of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Japan that produce whistles transmitted efficiently through environmental ambient noise. We compared the characteristics of the ambient noise in the dol...
Article
Animals should communicate each other with the most efficient signals in their habitats. Here we report the Indo-Pacific bottlenose dolphins (Tursiops aduncus) produce the whistles which travel efficiently under the environmental ambient noise in their habitat. The dolphins in the high ambient noise environment produced the whistles which have litt...

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