Resource: Anglerfish

Animals whose diets consist of other animals generally work much harder to obtain food than animals whose diets consist of plants. After all, plants cannot run away or resist, while prey animals must first be captured and subdued before they can be eaten -- and most try their hardest not to become a predator's next meal. In many cases, prey animals have evolved a heightened sense of awareness, speed and agility, or disguises, all of which help them to avoid predators. Keeping pace, many predators have evolved traits that make them more effective at catching their prey.

In general, carnivores use one of two different predatory strategies in their search for food. The more common of the two is called "active searching. " As the name implies, a predator using this strategy goes looking for food. Woodpeckers, for example, probe almost ceaselessly under flakes of bark in search of insects. Snakes slither into rodent burrows and other tight spaces in search of any animal that can be swallowed whole. Many other carnivorous mammals, including wolves and some species of cats, also go in active pursuit of prey. Typically, animals that use this strategy have physical or behavioral adaptations that make them more efficient pursuit predators. These include speed, endurance, cunning, and highly specialized sense organs or physical features for finding and capturing their prey.

The less common of the two predatory strategies is called "sit and wait. " Again, the strategy is as straightforward as its name. It involves no high-speed chases across the savanna -- nothing as physically demanding as that. Despite the apparent simplicity of this relatively lazy strategy, however, some of the animals that use it possess traits that are as fantastic as the turbo-charged speed of the cheetah. Mostly, sit-and-wait predators rely on very good camouflage to fool their prey into believing that no danger is near. Flounder and chameleons, for example, can change the color and pattern of their skin to perfectly match and blend in with their environment.

Ironically, a predator using the sit-and-wait strategy is often at the mercy of the prey animal. The predator can do nothing but wait for a creature to blunder into its grasp. In fact, it is not uncommon for some sit-and-wait predators to go several weeks between meals. However, the anglerfish seen in the video, as well as some types of snapping turtles, use a slightly more active approach. These creatures use parts of their bodies to lure curious fish and other creatures to within striking distance, dramatically improving the odds for success of an otherwise passive strategy.

Why do you think the butterfly fish didn't see the anglerfish?

Why do you think the anglerfish catches its prey so fast?

Can you think of two other predators that ambush their prey?