Identification
Known as terrestrial gastropod mollusks with shells. Not to be confused with sea snails or freshwater snails. Slugs are without shells. N. America has about 500 native species of land snails.
The majority of land snails are pulmonates meaning they have a lung and breathe air. Others have a gill.
They have a mantle(the flesh that essentially holds everything inside their body and attaches to the shell) with one or two pairs of tentacles on their head.
The eyes are typically carried on the first or upper set of tentacles. Not great vision though. Mostly blurry lights and darks.
The second or lower set act as a nose. Both sets are retractable.
The shell grows with them in size by the process of secreting calcium carbonate along the open edge and on the inner side for extra strength. The size and weight of the shell keeps them from growing extremely large, and is used to determine age.
Habitat
snails live where they can find moisture and darkness. marshes, woodlands, pond margins, flower and vegetable gardens, under leaves, mulch, rocks, logs, in cracks and crevices, and flowerpots and other yard fixtures. Snails can travel from place to place slowly if they need to. Mostly, snails are moved through flooding and streams
Nesting
The land snails with lungs have a full set of reproductive organs of both sexes and most lay clutches of eggs in the soil.
Behavior
They have a strong muscular foot and use mucus to enable them to crawl over rough or sharp surfaces and keep them from drying out. The motion happens through succeeding waves of muscular contractions that move down the foot. They move at the speed of 1mm/sec
The mucus lives a shiny slime trail behind them that can be visible for hours after they’re passed.
If conditions get too dry, they estivate (a stage of “sleep” that’s not quite as deep as hibernation) and stay that way until it rains. In winter, many species hibernate, in which their heart slows down from about thirty-six beats per minute to only three or four, and oxygen use is reduced to one-fiftieth of normal.
Offspring
The age of sexual maturity varies depending on the species of snail, ranging from as little as 6 weeks to 5 years. Adverse environmental conditions may delay sexual maturity in some snail species.
Most pulmonate air-breathing land snails perform courtship behaviors before mating. The courtship may last anywhere between two and twelve hours.
Each brood may consist of up to 100 eggs. Can lay eggs as often as once a month.After 2-4 weeks of favorable weather the eggs hatch.
Tiny snails hatch from the egg with a small shell in place. The shell grows spirally as the soft parts gradually increase in size. Most have shells that are right-handed in coiling or clockwise if you start at the center of the shell.
Most land snails live only a year but some larger species may live longer. There have been records of a snail in the wild living 10 years. In captivity, some have lived up to 25 years.
Predators
Lots of animals prey on snails, and they are used as food by humans in various cultures. Almost every group of land vertebrates preys on snails. Some invertebrates also prey on them like leeches, flatworms, and some caterpillars.
The most common enemies of land snails are small vertebrates, invertebrates, birds, and mammals. They are not usually victims of large animals. Among the predators are flies, mites, nematodes, millipedes, centipedes, some caterpillars and fireflies, leeches, beetles and their larvae, rats, mice, weasels, squirrels, toads, salamanders, turtles, blackbirds, wild turkeys and other Birds of the subfamily Tetraoninae.
And they also eat each other. Certain species such as the Rumina conch shell enjoy eating other relatives, usually garden snails (Helix aspersa). Haplotrema concavum is an American carnivorous predator snail that, in addition to worms, enjoys eating other snails that may be of the same species. Many of the smaller species of snails end up eaten by larger ones like the Decollate snail, which is a voracious predator that feeds on garden snails and slugs as well as their eggs.
Predators attack snails according to their size and capabilities. For the smaller ones, like nematodes or larvae, it is relatively easy to enter by the opening of the shell and begin eating the snail. The bigger ones can crush them or make a hole in the shell to extract the soft body.
In some cases, snails are victims of predators introduced into their habitat, that is, animals that do not belong to their natural environment which can be very dangerous for them. This has happened to the snail species Pseudocharopa whiteleggei, highly vulnerable to the black rat (Rattus rattus) introduced in Australia in the early twentieth century. This black rat has been key to the decline of the population of this species of snail.
In residential areas, pets can be predators for snails as well. They include cats and dogs. They may not need to consume them as food, but they are often curious as well as territorial. Some may eat them, but others simply kill them or just play with them.
How do snails defend themselves?
They may not look the most ferocious, but they are not completely defenseless against their predators either. To do this, they can use strategies such as the following:
– They retract into their shells.
As we know, they are not fast; Then, when they feel danger nearby, they lock themselves into their shell and cover the opening with a layer of mucus called epiphragm.
– They secrete extra mucus.
When an animal attacks a snail, it releases large amounts of mucus, perhaps to confuse or stifle the attacker. So far, it is not confirmed if the secretions of land snails contain toxic substances.
– They hide beneath the ground.
It is always effective to disappear from the sight of your predator.
– Live in areas with places to hide like rocks and plants.
Some dwell in places difficult to access like cracks or crevices or in the ceilings of some structures.
– Cryptic coloring.
The shell of most snails is brown or light brown, which sometimes makes them hard to see on the ground or in the trunks of trees.
– Flee!
Some snails prefer to escape from a direct attack. They can move swiftly if another snail is on top of them. Some manage to do it without their attacker noticing.
Their consumption is common, and millions are captured and consumed for food annually.
Human Danger
Humans are a huge threat to some snail species. Their consumption is common, and millions are captured and consumed for food annually. However, most snails used for food grow on farms, so the wild population isn’t threatened.
With so many predators you may wonder how the snails continue to survive. The fact that they can mate several times per year is very helpful; they can lay up to 100 eggs at a time which is another advantage. Even though they have a high mortality rate, their reproduction ratio is adequate to keep the number of snails suitable for survival.
Many experts feel that the abundance of snails helps to keep other types of animals thriving as well. As you can see from the list of predators above, there are a lot of animals that can benefit from eating these mollusks.
Diet
Need a strong source of calcium in their diet and environment to produce a strong shell. They eat leaves, stems, soft bark, fruit, vegetables, fungi, and algae. They feed primarily at night on decaying organic matter.
Fun Facts
Snails are grown on farms in some places for use as food.
The largest land snail is the Giant African Snail which can measure 7- 12 inches.
The smallest is the Acmella nana which can fit through the eye of a needle at .7mm this variety is extinct in the wild.
Roman soldiers used to carry snails for food.
The mucus of garden snails is used to treat wrinkles, spots, and scars on the skin
Snails host several types of parasites that, while may not kill them, they are capable of affecting or killing their predators or animals that eat the snails. Even humans who eat poorly cooked snails can become seriously ill.
Snail JOKEs
Why do the French eat snails? – They don’t like fast food
How do snails fight? – They slug it out.