Because of ethical reasons, most research has been carried out on rats and other mammals.

The impact on marine mammals by this system was certainly not a consideration.

In addition he did genetic research work on rare or endangered mammals.

They have been shown to cause a significant impact on ground nesting birds and small native mammals.

However, it may also prey on marine mammals such as seals.

Research on rats and other mammals had revealed similar patterns.

For a long time, biologists have been concerned about the effect of such noise on marine mammals.

Active at night, it feeds on worms and small mammals.

Some will feed on or near large mammals to find insects.

It seemed to have a worrisome effect on certain other mammals.