Manatees are intriguing and marvelous aquatic mammals. They typically live in shallow rivers, bays and coastal areas, preferring water that’s not deeper than 10 feet (3 meters). But on any day, they swim slowly and clumsily through the water eating underwater vegetation, such as water hyacinth, hydrilla, eelgrass and water lettuce. Then they come to the surface every four or so minutes to breathe in air. However, because they tend to swim closer to the surface, this places them at a huge risk of collision with watercrafts, a fact that has necessitated the enactment of manatee protection policies including no-entry zones and restricted speed zones in various waterways to protect the animals.

So can manatees see underwater?

Manatees have a profound eyesight. These animals can normally see a long way ahead of them. However, because manatees always reside in dimly lit habitats they are used to not relying often on clear vision for their daily life. Actually their vision only helps them make sense of the general shapes in the water and avoid colliding with things, and not more than that. Manatee eyeballs are positioned far back on the head and are about half as big as human eyeballs. This, coupled with the fact that their body length is about 2 meters (9.8 feet) and they weigh 362-544 kilograms (800-1,200 pounds), means their eyes are too tiny to meaningfully aid them.

In terms of structure, manatee eyeballs have rod and cone cells just like human eyes. The rod cells help the animals see in low light while the cone cells help them differentiate colors and contrast details. But even with such cells in their eyes, manatees are not able to discern much with their limited vision. The sea cows are only able to discern blue and green light pigments, but can’t recognize many other pigments. Manatee eyesight is categorized as poor, quite close to nearsightedness. And if they took human eye tests, they’d actually be classified as blind.

How do they manage it in the water with their poor eyesight?

The poor vision of manatees doesn’t hinder them from thriving in their aquatic habitats. While they do not discern much underwater, they actually do not require clear, keen vision to spot food and their poor eyesight is just enough for them to navigate the sometimes murky waters and locate tasty sea grass, algae and other aquatic plant life. Moreover, their bodies feature whisker-like hairs, referred to as vibrissae. These hairs are anchored in blood-filled follicles connected to approximately 50 nerves. When there are alterations in pressure due to surrounding motion, these follicles stimulate nerve impulses. This mechanism aids the animals in navigating their habitats.

When surrounding motion exerts higher pressure, these follicles initiate nerve impulses. This process resembles how a fish’s lateral line converts water movement into electrical energy through nerve impulses. So the vibrissae act as a sixth sense, enabling manatees to move easily in dimly lit environments. They are also very sensitive and can feel vibrations as low as a millionth of a meter. In addition to body hairs (vibrissae), manatees employ ultrasound frequencies for communication. They possess a kinesthetic sense for detecting low-frequency sounds, aiding them in adapting to their surroundings. Manatees lack natural predators, resulting in no heightened risk of predation due to their limited eyesight.

You’d likely be interested in discovering more intriguing facts about manatees. That’s why Captain Mike’s provides organized manatee tours, facilitating tourists in observing and swimming with these gentle creatures. At Captain Mike’s, skilled and knowledgeable captains will guide you. You’ll use stable, comfortable, and safe boats to explore manatee hideouts. You can interact with these fascinating mammals and gain insights into their behavior and thriving in their habitats. For more information on manatees, manatee tours and boat rentals in Crystal River, visit the “Captain Mike’s Swimming With The Manatees” site.