All about snails - 6

How do Land Snails Reproduce?

If you are entering into the world of snails, you will also begin to notice that the way in which they are built has allowed for their survival through centuries.  One of the ways in which this has continued to build is through the abilities to reproduce by these creatures.  The different features in which they can do this also provide them with the capacity to keep slugging on the land.

Reproduction of Snails

Snails will be able to reproduce differently than almost any other type of creature.  This begins with the build that all snails have.  Snails are considered to be hermaphrodites.  This means that every snail will have both male and female reproductive organs.  Most terrestrial gastropods are hermaphrodites. The only snails that have not adapted this attribute are some freshwater and marine species, specifically including Apple Snails and periwinkles.  These two types of snails still have separate male and female individuals.

The land snails will be considered sexually mature from one month and a half to 5 years, depending on species. This is because the life span of most land species does not last for more than five to seven years, allowing for a faster growth rate of the species.  The make-up of the snails will include their reproductive organs on the bottom of their body.  This is close to the front of their body as well, allowing for easier abilities to mate.

The mating practices of snails allow them to deliver eggs for new snails to be brought into life at a consistent rate.  Snails will go through a complete mating ritual with each other, usually which will communicate to the other snail for an average of two to twelve hours.  At the end of this ritual, the pair will fertilize the eggs in the other, so both of them will deliver eggs.  It is known that a snail can carry up to 100 eggs at a time.

When the eggs are fertilized, they will go through a process of growth inside the snail, until they are ready to be delivered. After that, both snails lay their eggs and bury them into separate places inside a small hole made in the topsoil in a cool place. This will allow the eggs to develop without being harmed.

It will typically take a snail egg two to four weeks in order to develop. (1) As soon as they hatch, they will immediately move into a survival mode.  This is because their shells will still be in a weak form.  Their reaction is to find calcium as soon as they hatch by either eating their own egg or eating other eggs in order to get the extra nutrients.  It will take around three months for the snails to completely form and look like a miniature version of an adult snail of their species.  While this takes place, they will stay in a nest that has been built for them, with the transformations being seen through a change in color, from a clear color into a blue then into the adult form that is representative of the species. After the snails are completely developed, they will detach from their parents.

The mating procedure of snails is one that moves through a specific process that helps the species to grow and survive.  This process start from the beginning of sexual maturity, followed by finding the right mate, locating and creating a place to deliver the eggs, hatching of the eggs and ending with the develop of small snails.
1- http://scienceline.ucsb.edu/getkey.php?key=2578

All about snails - 5

Snail Dangers and Predators

One of the main reasons why snails die is due to becoming a meal for other animals. We all know that snails are extremely slow creatures so they definitely aren’t going to be able to out run other animals in the wild. Many of the smaller species of snails end up being consumed by larger ones like the Decollate snail, which is a voracious predator that feeds from garden snails and slugs as well as their eggs. Other common predators include leeches, beetles, and caterpillars.

There is a sort of invertebrate predators of land snails, including beetles, flies, mites, and other snails, while shrews, mice, amphibians, reptiles and birds are the main vertebrate predators.

They have some other predators too that are much larger than these. Depending on where they live they may be eaten by frogs, toads, snakes, and a variety of different birds. Most of them find the snail to be very simple prey and since they are small, eating large numbers of them isn’t uncommon.

In some areas ducks and geese will feed on snails too. Many parks have small ponds where these types of birds reside. They will likely have lots of trees to which provide the shade for the snails as well. Even though these ducks and geese often get lots of food from visitors they still have a natural instinct to find various types of prey including snails out there in the wild.

In many areas domestic 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 of them may eat them but others simply kill them or just play with them. During some types of the year field mice may be out and they tend to consume snails as well.

Defense Mechanisms

Snails really don’t have much they can do but to hide from predators. The coloring of their bodies offers them a great way to hide. In fact, if you have a garden you may have lots of snails but you don’t see them unless you are actively looking for them. Their only real defense from some predators is the chance to put their entire body inside of the shell. However, many predators are able to break through it anyway.

Thickened shells have been another way to defend from predators as well as an increased secretion of mucus.

Human Danger

Humans are a huge threat to some species of snails. The consumption of them as a type of delicacy is very popular, especially among the upper class. Millions of them are captured and consumed for food annually. However, the majority of snails used for food are grown on snail farms so the actual overall wild population of them isn’t bothered.

This also helps to ensure that healthy snails are the ones that are being available for people to consume. When they are harvested then they are actually fed a special type of diet. This ensures that they will have a better taste than those that you just end up finding in the wild. Of course you will pay more for this type of snail as a food but most people find it to be delicious and well worth it.

With so many predators you may wonder how the snails continue to survive. The fact that they can mate several times per year though is very helpful. The fact that they can also lay up to 100 eggs at a time is another benefit. Even though they have a high mortality rate there are enough of them to help keep the number of snails out there at a decent level.

Many experts feel that the abundance of snails helps to keep other types of animals thriving as well. As you can tell from the list above, there is no shortage of animals that are able to benefit from the consumption of such small forms of life out there.

http://www.carnegiemnh.org/science/default.aspx?id=16822

All about snails - 4

Basic Land Snail Anatomy

The anatomy of a land snail is very different from many other animals in the world. Some people find them to be fascinating while others think they are pretty ugly. When you start to break down all of the parts of the body though they definitely have an interesting anatomy and physiology.

The shell of a land snail can be very different in size and shape depending on the species of snail it is. Some of them are coned while others are flatter. However, all of them have a spiral design to them, caused by the way land snails produce and growth their shells.

Shells serve as a way to protect snails from the environment and even from predators in some cases. However, many predators are able to bite through the hard shells with powerful teeth and jaws.

The shell of a land snail is made up of calcium carbonate. The shell becomes very strong and remains that way as long as the snail consumes a diet that is full of calcium. Without it the shell will start to crack. Since the rest of the body is very soft and slimy, they must have a hard shell if they are going to survive the elements in the world around them.

While moving, snails they leave behind a trail of mucus. This mucus acts as a powerful lubricant to reduce friction against the surface. This is why they are able to move upside down, around corners, and other situations.

Body parts of a land snail.

It is a myth that this mucus is going to make humans ill. Many people worry that snails being in their garden will ruin the foods grown there and make them unfit for consumption but that is all false.

They shell is a safe haven for the snails to reside in. When they sense danger around them, putting the whole body into the shell is their line of defense. You will also find that snails spend a great deal of time in their shell when the weather is very hot and dry. Otherwise their moist bodies will dry out.

Image under GNU license.

Author Original by Wikimedia Commons User Al2, English captions and other edits by Jeff Dahl

Snails have one or two sets of tentacles that are on top of the head. The number of pairs will depend on the species you are describing. For species with both sets of tentacles, you will find that the eyes are present on the longer set and smell in the shorter set. You may not always see these tentacles though as all land snails have the ability to retract them.

The snail has a very small cerebral ganglion that is known to have four distinct sections on it. Although this is a rudimentary brain, they have more ability for associative thinking than most people give them credit for. Some research shows that they do take part in associative thinking, which is based on conditioning and experiences that they take part in. (1)

The mouth of a snail is found at the bottom of the head, in close proximity to the tentacles.

Most land snails have a lung, so they breathe air. To do it, they breathe through a cavity called the visceral. There are many blood vessels here and the function is the same as what our lungs are able to do for us.

There is a foot on land snails, which allow them to move forward. There is contracting and expanding in this muscle that allow them to have movement. To make this movement smoother and to avoid injuries, land snails produce mucus to help the foot slide.

Beautiful Snail Shell

A gland in the foot produces the mucus that they glide along. Without this mucus under them, the environment would be too hard for their soft bodies to move along without injury.

Covering the foot and some internal organs there is a protective layer called the mantle. In some cases, it is also found around the shell to offer it additional protection. The mantle make the shell grow by delivering the secretions that will add to the shell.

If you watch how a snail looks before moving you will notice what appear to be spasms through them and then they inch forward. These are the muscles in the foot working. Even though they do move slowly there is a rhythm to it that they will follow over and over again. This can be fascinating to watch.

(1) http://www.telegraph.co.uk/lifestyle/9433231/Germaine-Greer-Snails-deserve-our-attention.html

(2) https://insects.tamu.edu/extension/publications/epubs/eee_00026.cfm

All about snails - 3

Life cycle of a Land Snail

The life cycle of any animal is the period involving the succession of one generation to the next by means of reproduction.

The reproduction process of the snail is one that has some unique patterns when compared to that of other land animals.

In other ways though the process is the same as what you would expect. In brief, mating, gestation period, egg dropping, egg hatching, maturing period and new snails are the main stages of this cycle.

The age of sexual maturity is variable from 6 weeks to 5 years, depending on species of snail.

Land snails engage in various types of courting rituals to attract mates. They can last mating from a couple of hours to half a day.

They don’t make sounds to call out to each other like many types of animals do because snails don’t have the ability to hear. So they use touching as a way of courting. They may cover each other in mucus that they produce from their bodies before mating.

It is believed this mucus also makes it easier for them to engage in the actual mating process. Once they have done so they will go their separate directions.

What is interesting is that each snail has the reproduction organs of both sexes. Even though, snails need to mate, they do not fertilize themselves. However, after the mating, both snails are able to deliver a set of eggs.

During the mating process both snails will conceive around 100 eggs and some of species up to 400. These eggs are extremely small and they will be deposited into the moist soil and covered. It can take up to four weeks for them to emerge.

Many land snails mate regularly as long as their living conditions are adequate for survival. These eggs will be deposited in moist ground where there is plenty of shade. They are under the top layers of soil but if you dig a bit you will be able to find them.

Even with so many eggs being deposited, only a fraction of these snails make it to maturity. Many of the eggs are washed away by rain and water people use in their yards and gardens or eaten by predators.

Once born, predators also attack young snails, because they are slow, they are plentiful and their shell is not hard enough to deter the attack of some predators.

When they offspring emerge from their eggs, they immediately need to get calcium into their bodies. They are born with a shell but it is in a fragile state. The calcium will help it to quickly harden up which offers them plenty of protection. The first thing they will instinctively consume after hatching is the shell of the very egg they came from, which is rich source of calcium. The shell continues to grow with the snail over the course of its life. The part of the shell it is born will end up in the middle of it when they are fully grown.

Snails grow rings inside of the shell as they grow. This is how scientists and researchers are able to get a good idea of how old they are. For the most part it seems that snails live a life that is slow paced and very basic. You can tell if a snail is full grown or not by looking at the part of the shell that opens up to the rest of the body. If there is a small lip on it then the snail won’t grow anymore. If it is missing then the snail still will continue to get bigger.

All about Snails - 2

Interesting facts about Snails

1. Some snails Hibernate.

Some species of snails actually hibernate during the colder months of the year. They cover their bodies with a thin layer of mucus, which prevents them from drying out. Sometimes snails are also able to hibernate in the summer to survive if they are faced with a severe drought. They live off of the stored up fat during this time of year. This process is one of the many reasons why they have been able to survive for million years.

2. Snails can have a long life.

The life span for snails depends on their habitat and the species. Some of them only live for about 5 years. However, others in the wild are believed to be up to 25 years old in unusual occasions.

3. There are huge snails.

The largest land snail recorded was 12 inches long and weighed near 2 pounds. It belonged to the Giant African Land Snail species. Other species are extremely small being only a few centimeters long when they are adults and weighing just a couple of ounces.

4. Snail Moving.

While moving, snails they leave behind a trail of mucus. This mucus acts as a powerful lubricant to reduce friction against the surface. This is why they are able to move upside down, around corners, and other situations.

5. Snail Mucus.

It is a myth that this mucus is going to make humans ill. Many people worry that snails being in their garden will ruin the foods grown there and make them unfit for consumption but that is all false.

6. Living with no rush.

Garden snails (helix apersa) a top speed of 50 yards per hour, this is about 1.3 cm. per second. While they don’t move fast, they do move at a very steady pace. The snails are one of the slowest creatures on the entire Earth.

7. Snails are Hermaphrodites.

Snails have the reproductive organs of both, males and females, which categorize them as hermaphrodites. However, they cannot create offspring on their own. They must mate with another and then both of them will have the ability to lay eggs.

8. Snail can see and hear.

Most land snails have two set of tentacles, the upper one carry the eyes, while the lower one has the olfactory organs.

9. Snails are nocturnal

They are nocturnal animals, which means most of their movements take place at night.

Snails don’t like the brightness of sunlight, which is why you will find them out more on cloudy days. If you keep on in an aquarium you want to make sure that too much sunlight doesn’t filter into the room. This can cause the snail to stop eating and to spend most of its time inside of the shell.

10. Get your size.

Snails range in size from a few centimeters to 12 inches in length.

11. Snail Care.

Snails will die if you put salt on them. Make sure you don’t offer these types of items to them when you see them or when you have one in captivity because their body can´t process these items.

12. Very Hungry.

The Giant African Land Snail is known to eat more than 500 different types of plants.

13. Small, not weak.

Snails are very strong and can lift up to 10 times their own body weight in a vertical position.

14. Big family.

It is believed that there are at least 200,000 species of mollusks out there including snails. Although only 50,000 have been classified.

1. http://www.in.gov/dnr/kids/5878.htm

2. http://www.ucmp.berkeley.edu/taxa/inverts/mollusca/mollusca.php

All about snails

What do Land Snails Eat?

Snails tend to feed on a variety of items found in their natural habitat. What they will actually consume depends on where they live and the species of snail that they are. Some common items for their diet include plants, fruits, vegetables, and algae. Plants that are decaying are often a good meal for them. Seeking for calcium to get a thicker shell, snails usually will eat the dirt.

Most snail species are herbivores, which means they have only a plant diet, but some species are carnivores or omnivores. You will likely find snails around your garden as this offers them plenty of fresh plants and leaves to eat. If you use herbicides or pesticides on your plants you may be causing the death of many snails without even realizing it.

Snails as pests

Large numbers of snails though in a garden or even where farmers are growing crops can quickly become a serious problem. They will consume enough of what it growing to ruin the hard work that has been put into the area. If you are talking about a location where someone is growing food to eat or to sell then their livelihood is also being compromised. This is why people do all they can to prevent snails from consuming the agricultural crops that they are growing.

To be more humane, many that have gardens or farms strive to trap the snails that are in the vicinity rather than killing them. They either release them back into new environments or they will sell them as a source of food. Some of the easiest ways to trap them is to place lids from jars with beer in them in the garden.

For farmers that have too much land to do this, they have come up with another way to prevent damage to their crops. This involves placing 6 inch screens of copper that is placed in the ground. The slime from the snails doesn’t seem to mix very well with the copper and that means they will stay away from the foods that are growing. This process has been very successful.

Snails have to feed on foods that include large amounts of calcium. This is necessary to keep their shell hard and protective like it should be. When looking for food they use their powerful sense of smell to find their food. Snails can breathe through their skin and through an opening called the pneumostome visible on the right side of their bodies. (1) Snails have very poor vision so they can’t see what may be very close to them, but that is compensated with an excellent sense of smell.

Snails are nocturnal so they will be looking for sources of food during the night or during the very early morning hours. (2) They will consume more food at the colder months ahead come. This is so they can store up fat reserves to live on while some they hibernate during the winter.

When food sources are very low in the summer or spring months, they may voluntarily put their body into a state of hibernation as well. This allows them to conserve energy and not need to forage for additional food. This is a mechanism that allows them to be able to survive in difficult conditions of drought. (3)

They have a tongue that is very rough and the technical term for it is radula. They have rows of very small teeth that they use to scrap against the foods they want to consume. When you have snails as pets you want to pay close attention to their diet. If you feed them anything containing salt or sugar they will die.

They are often said to be very noisy eaters. However, the sounds you hear aren’t them consuming the food. Instead it is a part of the body called the radula which is tearing on what has been swallowed so it can find its way to the digestive tract.

(1)    http://www.pbs.org/kcet/shapeoflife/resources/snail.html

(2)    http://pss.uvm.edu/ppp/pubs/el14.htm

(3)    http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7427.html

Empresa de Helicicultura Biojogral (Reportagem RTP2)

Uma reportagem bastante interessante acerca da constituição e do funcionamento da empresa Biojogral, dedicada à helicicultura e com uma vertente para prestação de formação nessa área.