But some scientists say they could make a run for global ascendancy if humans, as many biologists fear, precipitate a mass annihilation of less adaptable creatures.

Some biologists fear to disagree with him for fear of a thunderbolt impugning their intelligence or sanity.

In the next few years, as the parasite grows in number, as biologists fear, even greater damage could take place.

Just one of them had ever succeeded in rearing pups, and biologists feared that inbreeding had caused the isolated wolf population to stagnate.

And some biologists fear that as the bite of natural selection is relaxed by medical advances, the mutational baggage could become more significant in the centuries ahead.

The demise was so complete that up until the late 1980's biologists feared the extinction of this native fish.

Thousands of birds and marine mammals have been killed by the oil that spilled from the tanker, and biologists fear many more will die.

Humans may now be precipitating an extinction of comparable scale, many biologists fear.

Some biologists and hunters fear that the white tail may ultimately displace the mule deer in shared habitats.

Some biologists have also feared that this name would be offensive to some Native American tribes involved in the conservation effort.