Seahorses and sight: Seahorse eyes do not work in unison like human eyes do, so these fish can actually see in two different directions at the same time. With eyes moving independently of each other (one looking in front, one looking behind), the animal has a full 360-degree picture of its surroundings!
Because of their forward-facing position on the animal’s head, scientists believe that seahorse eyes enable binocular vision (which humans and many other species share). This type of vision is used to locate prey and assist with the small crustaceans that make up the bulk of their diet.
Frogs and hearing: It’s true that frogs do not have outside ears that direct sound inward to the eardrum as humans do. But most frogs do have an eardrum of sorts, an inner ear, and a middle ear. They hear with these structures and one more – their lungs! A frog has an unbroken air link from the lungs to the eardrums. Scientists think this link serves two purposes: to help the frog locate sound and possibly to protect its ears from its own raucous calls.
You can learn more about these remarkable life forms by visiting the Frogs! A Chorus of Color exhibit at the National Aquarium. Frogs are among the most visually stunning, vocally pleasing, and adaptive life forms on earth, but their chorus is fading due habitat destruction, climate change, and pollution. The beauty and elegance of frogs is often overlooked, but we invite you to take a closer look! And a good listen!
Damselfish and smell: Marine scientists working on Australia’s Great Barrier Reef have uncovered evidence that baby damselfish, only a centimeter long, manage to find the way to their home coral reef across miles of open sea by using their sense of smell!
In damsels and other fish, a pair of tiny nostril-like holes, called nares, open to a chamber lined with sensory pads. When water moves across these pads, chemical signals incite the fish to react. In baby damsels, the chemical makeup or “smell” of home (a rich mixture of the proteins and amino acids emitted by corals) encourages them to chose a current that leads to their original reef.
Sea anemones and touch: The sea anemone’s acute sense of touch has two very important roles – feeding and protection. Tentacles surround the end of the anemone’s body and mouth and each is lined with nematocysts, or stinging cells. Small sensory hairs on these cells can detect even the slightest touches and subtlest vibrations in the water. When the anemone senses prey – or a potential predator – it triggers the release of venom-laden, harpoon-like structures, paralyzing the food or enemy! Only the clownfish is immune to the sea anemone’s sting.
Catfish and taste: Imagine a big swimming tongue; in a way, that’s what a catfish is. The smooth scaleless skin of this fish is completely covered with taste buds – 250,000 cover a 6-inch-long catfish. (Humans, by contrast, have only 10,000!)
Most fish that have taste buds have only a few located in or near the mouth, but a catfish has dense concentrations of them in its mouth, as well as on its fins, back, belly, sides, and tail. Those covering the body detect chemicals to help locate food, even in dark, muddy water. The highest concentrations on the outside of the body are on its long, tapered whiskers, or barbels, which it uses as feelers to cautiously sample food before eating.