これまでに著者らは2基のハイドロフォンアレイを用いた複数のを対象とする位置推定手法を提案した。この手法は,鳴音の到達時間差による到来方向推定時に,その到来方向をもとに鳴音をクラス分けすることで,複数のの位置を推定する。本論文ではこの手法を改良し,途切れたクラスを直線近似を用いて結合するアルゴリズムを提案・実装し,これを評価する。また,解析により得られた5頭のに関して,ICI(Inter Click Interval)から推測される鳴音のターゲットレンジとクジラ間の距離について考察する。

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Bio-logging is an effective ecological survey method performed by attaching a recording device to an animal. This method is used for various animals, one of which is sperm whale. The sperm whale eats a giant squid in the deep sea, but the predation scene has not been recorded yet. In order to take the scene, biologists have attached a logger using a long pole. However, this conventional method requires experts and includes a risk of injury. To tackle the problem, we have proposed a logger attaching system using drone. In this paper, we performed field experiments to confirm feasibility of the system.

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Recently, bio-logging science has been conducted all over the world. The bio-logging is a method of observing ecology of animal with a small mounting equipment called a logger. Sperm whale is one of the target. The sperm whale fights against giant squid in the deep sea, but the scene has not been taken yet. Therefore, zoologists want to record the scene. So far the logger has been attached by using a long pole from shipboard. However, this approach requires several skilled operators and includes danger of injury. To tackle the problem, we propose a camera logger attaching system with a drone.

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A technique called bio-logging is utilized for investigation of sperm whales. zoologists conventionally attach a data-logger to only the back of a sperm whale. However, no one ever watch the sperm whale's preying because of darkness of deep sea. To tackle the problem, we have developed an underwater drone to attach the data logger at mouth area of sperm whales. The underwater drone has 6 thrusters for 6-DOF motions in water. Moreover, it is designed with a maximum speed of 1.2 m/s to chase the sperm whale whose speed is 1.1 m/s. It is tele-operated by an operator on a ship through a cable.

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大型の鯨類の骨格配置は十分に理解されておらず，それぞれの交連骨格によって配置は異なる．しかし近年，プラスティネーション技術を用いた標本の制作工程が報告された．この標本は軟組織が保存されているため，再現性の高い骨格配置であると考えられる．本研究では，その標本の外側観の画像を使い，フォトグラメトリーで得られた足寄動物化石博物館所蔵のの骨格の3Dモデルを重ねて骨格配置を立体で再現し，ほかの交連骨格と比較した．その結果，胸椎のカーブや肩甲骨の位置，椎骨に対する骨盤骨の位置に違いが確認され，骨格から得られた知見や現生の小型ハクジラ類のCTにより得られた画像とも整合的であった．しかしながらプラスティネーション化された標本は，標本化の際に多少のずれが生じている可能性もある．今後，漂着個体を解体しつつ3Dモデル化することで上記のポイントを重点的に調べる必要がある．また本研究では，この再現された骨格配置をもとに3Dモデルとして外部形態を再現し，体積を計測したところ22.77 m³（体長12.85 m）で，既存の研究と一致した．このことから，骨格の3Dモデル化を通じた体積推定は有効な手法であることが示された．

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オスの

(Physeter macrocephalus)は，性成熟前に出自集団を離れてオスだけの群れを形成する．商業捕鯨期には独身オス群と呼ばれる密集したオスの群れについて度々報告がなされたが，近年の調査でオスは一日の大半の時間散開して採餌しており，密集した群れ(クラスター)は滅多に形成しないことが明らかになっている．2019年9月16日，北海道根室海峡にの大群が来遊した．およそ1海里（1852m）の範囲内にいる約30頭が5分程度の潜水と浮上を繰り返しながら同調的に移動し，浮上時には様々なサイズのクラスターを形成した．この日確認された最大のクラスターは18頭で，根室海峡で調査を開始した2006年以降に目撃されたものの中で最大であった．この日観察した個体はいずれも体長10 m前後で，通常この海域で見られる個体よりも小さく，子連れの個体が見られなかったことから，性成熟前のワカオスだと考えられた．また船上からの観察中，この集団は一般的な水平移動速度よりも速い速度で移動し，メスの群れが捕食者に襲われた際にとるマーガレットフォーメーションに似た陣形を二度に渡って組んだ．今回のように大規模で密集したオスの群れやその行動についてはこれまでに観察例がなく，オスの社会構造を理解する上で重要な知見であると考えられる．

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Sperm whales are known to prey on giant squids, but no one has ever seen the moment of predation because of behavior in the deep sea. To capture the predation scene, we are developing the whale rover expected to walk on the body surface. Until now, the seventh prototype achieved absorption on the whale for a period of time, but we had no way to know if the rover had walked. In this paper, we proposed a system that can count steps by measuring the number of rotations of the propeller. We applied the developed system to the results of field experiments in Ogasawara, and showed that the rover achieved adsorption walking on the body surface.

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Sperm whales are known to have high diving ability and to prey on giant squid. Until now, several data (ex. diving depth, diving duration) have been obtained by bio-logging. However, it is difficult to photograph sperm whales preying on giant squid because loggers can adsorb only on their back. So far, we have developed a whale rover that can move in the head direction after adsorption. We have also developed a system to transport and adsorb the whale rover using a drone. In this paper, the results of field experiment using the developed system are described.

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Sperm whales are known to prey on mesopelagic cephalopods such as giant squid. However, their predatory behavior has not yet been recorded as photographs or videos. If such images can be captured, it will be a valuable clue to clarify the predatory behavior. Therefore, we are developing the “whale rover” that is attached to the back of the whale and moves to the vicinity of the mouth. In this paper, the improvement of the whale rover and the results of field experiments are described.

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大型の鯨類の骨格構造，特に肩甲骨の位置については，いまだ十分に理解されていない．本研究では，2024年に北海道浦幌町で漂着したの解剖標本をフォトグラメトリーで3Dモデル化し，2021年に北海道苫小牧市で収集された骨格標本と比較して，骨格構造の検討を行った．その結果，肩甲骨は頸椎の外側に位置することが示された．本研究は，解剖標本のフォトグラメトリーが鯨類の骨格構造の研究において有効な手法であることを示すとともに，骨格構造に 特化した写真撮影によるさらなるデータ収集の必要性を示している．

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There is a hypothesis that insists that sperm whales melt and congeal sperm oil in their head to adjust their buoyancy. This paper describes an underwater robot with a buoyancy adjusting system based on the sperm oil hypothesis. First of all, we chose paraffin wax as a substitute of real sperm oil and measured its buoyancy increase between liquid and solid states. Paraffin wax's melting point is relatively low and its volume difference between liquid and solid states is large. Then, we designed and developed an underwater robot. Six syringes filled with paraffin wax were installed in the robot and the wax was heated by nichrome wire to melt it. We measured robot's buoyancy increase and succeeded in making the robot surface and change its posture.

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In sites of the Okhotsk culture, bone, tooth and antler pierced disks were excavated. Some archaeologists used these disks for research on the transition of patterns from the Okhotsk culture to the Ainu culture. And they thought these disks were ornaments of belts referring to ornaments of belts for use by the Kuril Ainu women. Now, a compilation of these disks has advanced. We need to reexamination of these disks from the perspective of patterns, techniques for making materials, and so on. This paper takes up 7 disks excavated in the Kawanishi site of the Okhotsk culture, Yubetsu, Hokkaido. And I also introduce a whale tooth cut in half excavated in the same site. This material is an important archaeological fact indicating a process of making whale tooth goods. As a result, it is turned out that pierced disks excavated in the Kawanishi site were made of whale ribs, whale teeth, Hokkaido deer antlers and these disks were standardized.

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Sperm whales prey on giant squid. However, the predation scene has not recorded on video. Bio-logging is useful for surveying animals that live in inaccessible area. In contrast, it is not easy to mount a camera to sperm whales. To tackle the problem, we have developed both an attaching system with a drone and a dropping-type adsorption logger. It is desirable that the logger can be attached not only to the horizontal body surface but also to the sloped body side surface. In this paper, we clear the effects of center of gravity for adsorption capability for the slope.

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