1.北海道長万部地方より採集した49例および北海道大学に所蔵されていた125例のエゾヒグマ標本について, 犬歯歯根セメント層に見られた年輪構造および歯根の発達程度を基準として年齢査定をおこなった。
2.エゾヒグマの永久犬歯歯根は0歳では未発達であり, セメント層の沈着は, 歯根の形成の進んだ1歳の夏に初めておこると考えられた。
3.毎年継続して一定地域で捕殺されてきた長万部標本, また不特定の時期および場所より集められた北大所蔵標本のいずれも年齢構成に顕著な性差は認められず, 全体として老年齢層が少なく, 若年齢層の多いピラミッド型が見られたが, 0～1歳は, 2～3歳より逆に少なくなっていることが認められた。
4.0～1歳の年齢層が, 2～3歳の年齢層より捕獲数が少ないことの理由として, 1.5歳までは母グマと共に行動し, 春, 冬眠穴から出てくるのがおそいため捕獲されにくいこと, 逆に2～3歳では分散期に入り動きが広くなり, また冬眠穴から出てくるのが早いという理由が考えられた。

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Effect of passage forests on sika (Cervus nippon) was examined by deer-trail mapping in Omote-Nikko, Tochigi Prefecture, from May 1973 to October 1974. The study area embraced about 80 ha. The passage forest was a striped larch (Larix leptolepis) forest less than 50m wide, remaining uncutted in clear-cut area. Deer-trail density was the highest in the edges between the middle-aged larch plantations and the young. The next highest density was in the passage forests. The lowest density was in the middle-aged larch plantations. Among the young-aged larch plantations, the density was not significantly different. Of three passage forests in the area, two were surrounded with a vehicle road, cliffs and steep slopes. In those passage forests with such interfering factors, deer-trail concentration was not clearly observed. However, after snowfall, deer footprints were abundantly appeared in the passage forests, the forest edges and the oak forests along a gully, but scarecely in the young- and the middle-aged larch plantation. Those high densities of deer-trail in the forest edges and the passage forests were seemingly caused by“edge-effect”.

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北海道石狩防風林において1966年および1967年の5-11.月に採集したエゾヤチネズミ764個体について齢査定を行ない, 個体群構成, 繁殖活動および胎仔数の変化を調べた。
1. 早春の個体群は主として越年個体からなり, 性比は雌の方が顕著に多かった。越年個体は8月まで急減し, 特に雄の減少が著しかった。当年個体は厳冬期から少数が現われ始め, 5月以降に増加し, 8月以後には個体群の80-90%以上となった。当年個体全体の性比はほぼ1: 1であった。
2. 越年個体は寿命直前のものを除き雌雄とも常に性成熟状態にあった。当年個体は雌雄とも繁殖期初期に生れたものの一部だけがその年の繁殖期に成熟したが, 成熟雄は雌の半数以下であった。各調査区とも成熟した当年と越年雄の合計数は雌のそれより著しく少なく, 通常半数以下であった。当年雌の成熟化に対する越年雌の存在の影響が示唆された。
3. 妊娠のピークは7月で, 出産期は7月に一回のピークをもつ2-10月と推定された。秋の繁殖活動は2年とも認められなかった。
4. 当年個体の成熟化の状況や秋繁殖の欠除などは, いずれも従来から知られている高密時の状況に合致するものである。
5. 約9-12ケ月齢の越年雌がもつ胎仔数は6月以前のもの (平均6.28) が7月以後のもの (平均4.77) より有意に大きかった。

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1) Clethrionomys rutilus mikado THOMAS, released in a population cage consisting 24 water tanks connected by wirenetting tubes, formed a breeding unit or a colony. 2) Nonpregnant adult females of the colony did not establish their own sub-territories, living at peace with other members of the colony. 3) About on the sixth or the seventh day of pregnancy female became aggressive, driving away other members of the colony from its proximity. 4) A few days before parturition female settled in a more carefully constructed nest for rearing offspring and she defended an area surrounding the nest against other members of the colony. 5) From the second through the forth day of offspring territorial characters of the nest and its surroundings were most firmly establishd. That is, other members of the colony strained every nerve in the vicinity of the nest and they kept a respectful distance from the nest. 6) On the fifth day of offspring mother became slightly less aggressive than before, though the territorial characters of an area around the nest, especially those of the nest itself were firmly maintained. 7) On the 15th or the 16th day, at which time the young began to actively move out on their own, mother became specially shy and considerably less aggressive. 8) Unless mother was pregnant, on the 17th or the 18th day, at which time the young became completely independent, mother became definitely inferior to adult males and she abandoned the nursing nest, building a simple sleeping nest. She again lived at peace with other members of the colony.

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The otters (presumed as Amblonyx cinerea) were observed nineteen times during the period from November 1974 to February 1975 in Padas bay, Sabah, Malaysia. All of these nineteen observations were done in daytime and at eleven out of them they formed a group consisting of 4 to 8 otters. And thier food habit, vocal sounds and other behaviors that we observed are reported.

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