摘要
白鱀豚的体色较为单纯,背部青灰色,腹部为白色,但颈部及尾部有较为明显的斑纹。用牙齿作为鉴定年龄的材料,牙齿的外形和髓腔的大小可以判别属幼年、成年或老年豚。白鱀豚的成熟年龄,雄性为4龄以上,雌性为6龄以上,生殖交配期可能在4—5月份。白鱀豚在长江中游是以淡水经济鱼类为食。营集群生活,对流速有明显的选择性,群体巡游前进时,顺流游速为7.5—9.7公里/时,顶流游速为2.7—4.9公里/时。提出了白鱀豚年龄与体长的关系式及体重、体长和体围的相关式,可供有关研究工作者参考。
This paper embodies preliminary biological research of Lipotes vexillifer, including body color, age, growth, diet, and reproduction behavior, Specimens were caught from the middle reaches of the Changjiang River in 1979 and thereafter.
The body color of Lipotes is rather simple, being light gray dorasally and white ventrally. However, there are conspicuous decorative marks on its neck and tail. Teeth of Lipotes have been used for the determination of the age. Based on the outline and the pulp of the teeth, youngs, adults and old individuals are distinguishable. The relationship between age and body-length are as follows:
In general, females are larger than males of the same age, and, statistically, six morphological parameters are significantly different between both sexes. To describe the relations among various bodily indices, the formula W=aL^(b_1)S^(b_2)(W, L and S denote weight, length and girth, respectively) is more authentic, and W=0.003418 L^(1.2681) S(1.1949) is available to calculate the weight of an animal during field survey or whenever the animal is unable to be weighed.
The mature age of male dolphines is over 4 years, of females is 6 years. Copulation probably takes place from April to May. Lipotes feed on freshwater fish and live in groups. Their preference for certain water velocity is obvious. Their cruising speed is 7.5—9.7 km/hr. when following the water current, 2.7—4.9 km/hr. when again st the current.
Lipotes is mild in nature, causing no harm to other aquatic mammals and human being. In the Changjiang River, they were found to live with Neophocaena in same habitat.
