Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that o...Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that of Neophocaena 0.2--0.5 sec. In Lipotes,a short divewould take 10--20 sec and a long dive up to 1--2 min (average value being 31 sec). InNeophocaena a long dive would reach a maximum of 65 sec with an average of 17.5 sec.Lipotes has a pair of functional eyes. The selective secondary atrophy of a number of eyemuscles and nerves and the position of the eyes in the head correspond with the physical con-ditions of the environments so that the field of vision is directed forwards and upwards. When pursued by motor boat, both species react with a long dive and a change of direc-tion under water. With the Baiji this would occasionally cause fatal injuries by thepropeller of the ship. Such a case seems much less often with Neophocaena. The populationof Lipotes is at present very small.In the stretch of the river (between Nanjing andTaiyangzhou) under exploration, we found scarcely more than one dolphin per 4 km. Thecause for its scarcity is mostly due to accidents or wounds caused by propellers.展开更多
From August 25,2006 to August 15,2007 in the open water of Tongling Freshwater Porpoise National Nature Reserve,the diurnal behavior and time budget of a pregnant Yangtze finless female porpoise(Neophocaena phocaenoid...From August 25,2006 to August 15,2007 in the open water of Tongling Freshwater Porpoise National Nature Reserve,the diurnal behavior and time budget of a pregnant Yangtze finless female porpoise(Neophocaena phocaenoides asiaeorientalis)was observed using focal-animal and continuous sampling methods.The results indicated that:1)the female predominantly invested its time in feeding(66.0±1.1%,Mean±SE),followed by traveling(11.5±0.3%),resting(10.5±0.5%),socializing(9.8±1.1%)and other(2.1±0.1%),2)among different months,it showed significant differences for each of the above behaviors except traveling,3)each of the five behaviors was significantly different among the 11 periods of the day,and 4)significant differences were observed for each of the five behaviors across the five zones of the water.展开更多
文摘Lipotes usually occurs in pairs or in small loose groups. The calves are born in March-April.The Finless porpoises are usually seen in groups of five or six individuals.The blowof Lipotes lasts 0.2--0.6 sec and that of Neophocaena 0.2--0.5 sec. In Lipotes,a short divewould take 10--20 sec and a long dive up to 1--2 min (average value being 31 sec). InNeophocaena a long dive would reach a maximum of 65 sec with an average of 17.5 sec.Lipotes has a pair of functional eyes. The selective secondary atrophy of a number of eyemuscles and nerves and the position of the eyes in the head correspond with the physical con-ditions of the environments so that the field of vision is directed forwards and upwards. When pursued by motor boat, both species react with a long dive and a change of direc-tion under water. With the Baiji this would occasionally cause fatal injuries by thepropeller of the ship. Such a case seems much less often with Neophocaena. The populationof Lipotes is at present very small.In the stretch of the river (between Nanjing andTaiyangzhou) under exploration, we found scarcely more than one dolphin per 4 km. Thecause for its scarcity is mostly due to accidents or wounds caused by propellers.
文摘From August 25,2006 to August 15,2007 in the open water of Tongling Freshwater Porpoise National Nature Reserve,the diurnal behavior and time budget of a pregnant Yangtze finless female porpoise(Neophocaena phocaenoides asiaeorientalis)was observed using focal-animal and continuous sampling methods.The results indicated that:1)the female predominantly invested its time in feeding(66.0±1.1%,Mean±SE),followed by traveling(11.5±0.3%),resting(10.5±0.5%),socializing(9.8±1.1%)and other(2.1±0.1%),2)among different months,it showed significant differences for each of the above behaviors except traveling,3)each of the five behaviors was significantly different among the 11 periods of the day,and 4)significant differences were observed for each of the five behaviors across the five zones of the water.
