The practice of actively defending a territory against intruders or opponents is very common in the animal kingdom.

Stingrays generally do not attack aggressively or even actively defend themselves.

Neither would he use the immense psychic force of his trained circle to actively defend the Tower.

Whether to defend actively or passively is an ever-recurring problem for the defenders.

He later wrote about the case against Intelligent Design and actively defended evolution.

But the ship's brain continued to operate the defensive systems, and a battleship that was actively defending itself took a lot of killing.

Territorial animals actively defend the area in which they live and more importantly on...

Salamanders may actively defend themselves once they are grasped by a predator.

We therefore actively defend much stronger integration of social and environmental criteria into trade agreements regarding fishery products.

During the 1980 campaign Brown actively defended the Carter administration's policies, speaking frequently on national issues in public.