The existence of reproductive isolation, so that these situations can not occur, even if there are some individuals of different species sometimes complete the mating, but they generally can not produce offspring, or produce offspring can not continue to reproduce

Although scientists did find that people still have consciousness at the time of death, but the consciousness does not stay for a long time, may not have time to react, the consciousness disappeared

In the wild, wolves are pack animals, and by living in packs they stand at the top of the food chain, but despite this, they face daily threats