艾虎对不同猎物的选择性

在室内条件下,将高原鼢鼠(Myospalaxbaileyi)、高原鼠兔(Ochotonacurzoniae)和根田鼠(Microtusoeconomus)作为艾虎(Mustelaeversmanni)的猎物选择对象,研究艾虎对猎物的选择性及艾虎捕杀猎物的行为时间分配。实验结果表明:艾虎对三种猎物的搜寻时间和搜寻频次基本一致,在搜寻猎物的过程中并非已知洞道系统中所存在的食物信息,是一种机会主义的捕食者;艾虎除了具有典型鼬科动物捕杀猎物的方法外,能够根据猎物的大小、活动性和反捕食能力采用不同的捕杀方法,在捕杀猎物的过程中首先捕杀高原鼢鼠,其致死部位全部为头部,其次捕杀高原鼠兔,其致死部位除了头部外,明显增加了颈部的比例,最后捕杀根田鼠,其致死部位主要是头部和胸部;艾虎在捕杀猎物的过程中,追击根田鼠的时间最多,追击鼢鼠的时间最少,而用于捕杀根田鼠的时间最少,用于捕杀鼢鼠的时间最多,艾虎捕杀高原鼠兔后单位时间内获得的能量值最大,其次为捕杀高原鼢鼠,而捕杀根田鼠后单位时间内活动的能量值最小。因此,在室内条件下艾虎对猎物的选择性主要依赖于其本身处理猎物的行为时间分配和猎物的反捕食行为,使单位时间内获得的能量值最大.

Prey selection by the steppe polecat Mustela eversmanni

Prey selection and foraging behaviour of the steppe polecat Mustela eversmanni were investigated with plateau zokors Myospalax baileyi, plateau pikas Ochotona curzoniae and root voles Mirotus oeconomus offered as preys for paired comparisons in the laboratory. The time and frequency of the polecat searching different preys and burrows were nearly the same. The polecat attacked virtually all prey offered and thus exhibited opportunistic foraging behaviour. However, it did not captured all prey with equal sequence. It first captured the zokor, then the pika and last for the root vole. In addition to using the typical musteline killing method of biting the nape of the neck, the polecat evolved a variety of killing methods suited to a range of prey types depending on the activity, size and anti-predation ability of prey. The zokor was bitten on the head, whereas the pika was killed by bites to the head or throat and the root vole was killed by bites to the head or chest. The time polecats pursued the root vole was the longest, followed by that used in pursuing the pika and the zokor. However, the time of the polecat used to kill prey was reversed for the three prey species. So the polecat depended on its prey handling time and behaviours of prey to select the prey and get the largest net food value.