It's a War Out There
The enemy prowls the night skies, searching. But its would-be victims may have sensitive sonar detectors, allowing them to flee before detection. If the prey is spotted on sonar, the prey has counter measures, even jamming the enemy's sonar.
No, this is not a scene from some modern battlefield. Rather, it is a description of things going on all around us. Many insects – including moths, beetles and katydids – have sensors that can detect a bat's sonar before they are spotted and targeted by the bat. When targeted, moths will either fold their wings and drop to the ground, or they will spiral upward erratically. The bat never knows what to expect. Other moths will send out high-pitched squeaks that some scientists think disrupt the bat's sonar.
While most fish cannot hear at the frequency of the dolphin's sonar, the American shad can. Lab tests have shown that the shad will move away from sounds that simulate foraging dolphins. If the sound becomes louder, the shad will form themselves into a tight ball at the opposite end of the tank, making any single fish less likely to be the dolphin's victim.
Our greatest enemies – sin and its results – are not so easily evaded. But thank God that we can flee to the wounds of Christ for forgiveness of our sin so we may know God's love.