Here are the 9 amazing facts about snail eyes. In this article, we have explained the types of eyes in snails and how their vision works.
Do Aquarium Snails Have Eyes? Yes, aquarium snails have a pair of eyes located on the top or base of their long antennas known as tentacles. Their exact location depends upon the types of snails. Some snails contain primitive eyes with the common feature of seeing the object shadow like a sense presence, while another has vesicular eyes with better vision properties.
- 1 Do Aquarium Snails Have Eyes?
- 1.1 Types of Eyes in snails
- 1.2 Carnivorous Snails Have Developed Eyes than Herbivorous Snails
- 1.3 Functions of Eyes in snails
- 1.4 Eyes location
- 1.5 Different snails have a different number of eyes
- 1.6 Snail vision quality
- 1.7 Can snail differentiate color variation?
- 1.8 Snails Rely on Sense of Smell and Touch for Navigation
- 1.9 Do snails regenerate their eyes?
Do Aquarium Snails Have Eyes?
Snails are tiny and strange kind creature that can present both on land and in water. Around 150,000 different snail species living in a range of habitats and have sensory cells ranging from primitive to more advanced ones with better sensing properties.
One of such organs is the eyes. There are a pair of eyes in every species of snails. However, their exact location depends on the type and natural habitat of snails.
They are located on the base of their stalking tentacles in aquariums’ snail while antennae for land snails at top.
The eyes of the snails contain the evolutionary process various species develop the best vision associated with features.
In this article, we will discuss different eye types, functions, and other snail features.
Types of Eyes in snails
Snail’s eyes look like black dots on top of their tentacles or the top of their heads. They are in the shapes of cups.
The eyes of different snails are divided into two major categories, like primitive eyes similar to pinhole cameras to differentiate between light and dark vesicular ones evolve, contain function almost the same as those of human beings.
These simple cup-shaped develop by stress on the snail skin and light-sensing cell on the end of that pit. These eyes can only differentiate between light and dark.
They can also determine the direction of light and plan their response accordingly. They cannot distinguish between object shapes and therefore cannot see the pictures. These eyes present in slow-moving herbivorous snails.
The evolution of the primitive eyes results in the deepening of cups and narrow field of view. It results in a still darker image due to the small amount of light but with sharper boundaries.
The next improvement is the presence of reflective gel-type secretions in the internal cavity of the eye. It breaks the incoming light rays and makes the image brighter.
They have developed eye parts as a result of improvement on a need basis. Improved portions are the pupil and a transparent layer for eye protection.
A round bubble in place of reflective secretions results in better image and quality of vision improved.
Most refined eye having visible quality comparable to the fish found in palmonite snails such as Roman snails. They widely find as aquarium snails because of their improved quality.
Light Sense Cells
Snails also have light-sensitive cells all over their body to detect light variation in their surrounding. They plan their response as soon as any shadow falls on them and try to hide in their shells. With help, they can see in the dark.
Carnivorous Snails Have Developed Eyes than Herbivorous Snails
Improvement in eye function depends on their use, diet, and environmental conditions. Herbivorous snails remain immobile most of the time and take their food from stationary sources. Therefore they contain less develop or primitive eyes.
Carnivorous snails assess and locate the prey and therefore improve eye parts as a result of evolution. Some of the species have even developed versions of vesicular eyes.
Functions of Eyes in snails
Eyes are present on the tentacle top or at the base, and the tentacle also has the sensory and olfactory organs which use to sense smell and touch.
Eyes with different shapes in various snails have many functions like they can differentiate color shades, and some are color blind face difficulty to see the color picture.
It is also useful to find out their prey, and the target gets their way. Some snail eyes provide clear vision, while others give blur vision. In the blur vision case, snail also uses the sensory organs which help them.
Snail belongs to the phylum Mollusca in which those animals are available having no vertebrates. Snails have sensory organs, which are known as tentacles.
It holds two common pairs known as ocular tentacles because it contains eyes present at their tips and large. These also consider as the upper pair.
Some of them contain these pairs at their lower side, known as the oral tentacle, and identify the odor with sensory organs.
Some carry only one pair of tentacles like they have the absence of ocular tentacles. Such type of snail species contains the eyes which are present at the base.
Different snails have a different number of eyes
Some of your aquatic snails consider as blind snails because they contain no eye pair or do not see the image. Such types of snails use tentacles because of the eye’s absence.
These snail lack eyes, do not stick to one thing, use their senses to identify different objects do their activities with the help of various senses like odor and touch.
It includes the blind snail species like the Subterraneous groups in which Cecilioides acicula and Roman snail also includes in this type with no eyes.
Different snail species contain a different number of eyes. Aquarium snails commonly hold 2-tentacles pair means 4-tentacles at their base while the land snail contains 1-tentacle pair it indicates that they have only 1-eye like the Grapevine snail.
They can navigate their food with chemosensory organs like they can use the touch, odor sense to find out their food and reach toward their destination.
Snails contain various eye types and structures consist of pinhole type eye, while vesicular eyes have the same functioning like the human eye.
Snail vision quality
Your snail has the best, and improper vision quality depends upon the snail types and their food. Each snail has its ability of vision like the herbivores and carnivores snail.
In this case, carnivores have the best vision ability compare to the herbivores snail and detect their prey and target with ease.
Can snail differentiate color variation?
You can see the snail cannot do color variations because the retina does not contain the photosensors.
Some of your aquatic pets, like the Apple snails, cannot differentiate the color shades because of the absence of sensitive color cells.
These are known as a color-blind snail. Some snail has cup-shaped eyes, which can define the color shades and identify the light source. But these types are not able to see any object.
While marine snails with cup-shaped eyes contain the best vision ability and can see the image, but the light source is not the best picture appears dark and limited. It includes some species with such properties are the Ormers and Trochidae.
Differentiation of prey and target
Your snail also contains the light-sensitive cells which present all over their body. It also indicates the shadow reflex in which shadow falls and shows the presence of the predator.
Many aquarist snail species like the marine and freshwater include the Apple snail of Ampullaria species.
It contains the vesicular eye with the best visual properties and recognizes its prey, but most of them still depend on the prey’s smell, which attracts them and makes them hunt the prey.
Snails can also rely on the sense organ in which different senses use like touch, smell. You observe that the sense organ carries or detects the surrounding information and sends it in the form of an impulse to the nervous system.
These cells are present in its tentacles and other parts of the body like the head and lips. For your aquatic pet breeding, snail relies on the smell and touch sensors to navigates its partner, and visual capacity is not suitable and has the hearing issue, sense the vibration by the sensory cell.
They find their partner by the smell of hormones. Snails have the olfactory neurons at the tentacle top, find the food with the sense of smell and touch, and find their direction.
Do snails regenerate their eyes?
You find that aquarium snails can regenerate their eyes, like the Mystery snail, pulmonate snail, and Helix aspersa can regenerate their eyes and the tentacles with ease.
They can regenerate with inner tentacles, release some secretory substances, develop the outer tentacle epithelium sheath and eye development.