Generally, when we say "whiskers," we're talking about mammals.

Most mammals have whiskers, but some are more obvious than others. For example, cats' whiskers get a lot of attention. Whiskers are specialized hairs. If you could watch the early development of a cat, you would see that the same kind of cells that later make fur became whisker-making cells, they just developed a bit differently. Whiskers are a lot longer, more rigid, and have a lot more nerves attached than regular hairs.

Whiskers are good at sensing vibration and air movement. If you were a cat hunting at night, or a mouse trying to avoid predators at night, whiskers would help you to feel the movement of air that signals something is moving around you. Where I went to college there was a blind harbor seal that was fat and healthy. It used its whiskers to find fish in the water. If you see a harbor seal out of the water, their whiskers don't look helpful, but if you see them underwater, the whiskers are all spread out and sensing water movement.

Generally, when we say "antennas," we're talking about arthropods (arthro=joint, pod=foot), like insects and crustaceans (lobsters, shrimp, and such).

Antennas are not hairs. They have a hard outer shell--the exoskeleton. They also have a lot of nerves connected to them. Antennas have some of the same function as whiskers. They can sense movement in air or water. They can also sense chemicals in the air or water in many species. They act like our noses in that way. They can also help with balance like our inner ear.

Notice that both whiskers and antennas are on the head. Why do you think that is?

Great question! Whiskers are elongate, specialized hair. Hair is body covering (which is made of a protein called keratin) that only mammals have--helping to keep them warm (except for groups such as whales and humans which have secondarily reduced the amount of fur they have). The function of whiskers is debated, but they may be helpful in navigating in the dark--like a walking stick for the visually impaired.

Antennae are similar-looking structures seen in many animals with exoskeleton (skeletons on the outside of the body--as opposed to the internal skeleton you and I have--and all other animals with backbones). Antennae are common in arthropods--animals such as lobsters, shrimp, insects, spiders, all of which have exoskeletons. These structures sense touch, heat, sound, smell, etc.

So, although whiskers and antennae are superficially similar, they're fundamentally different structures.

Whiskers are a specialized type of hair found in mammals. These special hairs are very sensitive and let the animal have a sense of touch through the whisker.

Antennae are much more complicated, but are more similar to extra tiny arms and they are only found in arthropods, which includes insects and crustaceans. There are a wide variety of things that they can do, including taste, smell, touch, sense heat and sound, and even swim.

Whiskers are long hairs that animals use to sense things in their surroundings. Research has shown that whiskers help with locating things, detecting movement, discriminating textures and shapes, maintaining equilibrium, fighting, and so on, but mainly with the tactile (touching) sensations. Antennae are not hairs, but are a much more integral part of the body on arthropods (scorpions, spiders, crabs). In addition to helping with the sense of touch, antennae also help insects taste and smell (diamondback moth), orient their bodies (monarch butterfly), mating (African cotton leafworm), as well as other functions that we do not understand yet.

What antennae sense and how they sense are different for different animals, but to summarize, antennae have a wider range of functions than whiskers, and are connected directly to the nervous system of the animal whereas whiskers are connected indirectly (there are no nerves inside the whiskers themselves).

Whiskers and antennae are fundamentally different structures, though they can have similar functions. Whiskers are a specialized type of hair found on most mammals. Like other types of hair, whiskers grow from follicles embedded within the skin. However, whiskers are typically stiffer, have follicles which extend deeper into the skin, and have far more nerves surrounding their follicles. This makes whiskers highly sensitive to touch. Animals use their whiskers somewhat like humans would use hands and fingers to explore the world and help navigate; muscles around the follicles allow animals to move their whiskers and "feel" objects. In addition, whiskers are sensitive enough to detect vibrations in the surrounding air. This can help with hunting and catching prey.

Antennae are sensory appendages found on all insects and crustaceans (which actually have 2 sets of antennae). Antennae are made of 3 main parts: the scape (attaches the antenna to the head); the pedicel (a muscled section that permits additional control over antenna movement); and a flagellum made up of many flagellomeres which contain sensory cells. Note the significant structural differences that antennae have muscle connections within the appendage, not just at the base, and have specialized cells along the structure rather than surrounding the attachment point. Depending on the exact sensory cells, antennae can be used to sense touch (like whiskers), but also to temperature, smell, and taste. Many insects also use their antennae for locomotion (e.g., some moths in stabilizing flight or in certain crustaceans as an aid in swimming); navigation (monarch butterflies use their antennae to locate the sunduring their migration); and communication (colony insects like ants being one example).

Other types of animals have similar features. For example, a few species of birds have feathers which are used essentially the same way as whiskers. Likewise, some fish have whisker-like appendages known as barbels.

Whiskers are little hairs on the faces of mammals. Antennae, or 'feelers, are pairs of stiff jointed things sticking out of the heads of arthropods.

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Whiskers are little hairs that stick out on the faces of mammals. There are lots of nerves at the places where whiskers come out of the face.

My guinea pigs use their whiskers to feel if something is close to them.

From Wikipedia: Antennae, of 'feelers', are pairs of things that stick out on the heads of insects and spiders and crabs and lobsters and other arthropods.

Antennae always have at least 1 joint, or sometimes lots of joints, so they can bend. Antennae sense different things, such as touch, smell and taste. Antennae on some different types of arthropods sense different things, including also sound and heat.