Lymnaea stagnalis

Lymnaea stagnalis is a fresh water snail which is also known as the great pond snail. They are widely found in Britain, Canada and northern continents of the world. They belong to the family Lymnaeidae and are known to inhale oxygen from water.

Common Name

This snail is known by its common name Great Pond Snail.

Description

Here is a general description of how these snails look.

Color : The snails are yellowish grey. They have shells that are shiny yellowish brown in color.

Size : A full grown adult is 45 to 60mm tall. These pond snails have large heads.

Picture 1 – Lymnaea stagnalis

Shell : The shells are tall and slender being a bit pointed on top. The size of shells ranges between 4.5 to 6cm. The wall of the shell is soft and translucent. There are scattered marks on the shells with lines indicating span of growth. The shell surface is also dented at some points.

Tentacles : These snails have flattened tentacles.

Distribution

These species are only found in the northern continents of the world. They are native to the British Isles residing only in Great Britain and Ireland. They are largely scattered across Cambodia, Canada, Poland, Czech Republic, Ukraine, Sweden, Switzerland, Russia, Germany, Slovakia and Netherlands.

Habitat

These snails are largely freshwater animals. They also prefer living in waters that flow slowly and in stagnant water bodies.

Behavior

There are some interesting behavioural traits found in these snails.

• They are often called ‘large breathing’ as they inhale and exhale oxygen from water with the help of their lungs. This trait makes them adaptive in any type of environment poor in oxygen.
• They respond to any harmful stimulus by completely retracting itself inside the shell.
• At times they also expel blood from their internal pores when threatened by some external stimuli.
• It can turn cannibalistic at times and eat its peer snails.
• The snails leave eating marks after they have finished eating their food.
• Due to having a diet that includes animals, these snails can get into attacking mood at times.
• The snails often move up to the surface to inhale air.
• They prefer still water.

Diet

This species eat plants and animals. They mostly attack newts and small-sized fishes besides having a taste for water beetle larvae. They are often found to show cannibalistic behaviour, eating smaller snails in the ponds.

Picture 2 – Lymnaea stagnalis Image

Predator

Tests were carried out on these creatures which involved some of the species being reared in laboratories, that resulted in these snails responding to the scent of crayfishes. Increased sensitivity towards crayfish has proven the crustacean to be the only predator detected by these invertebrates.

Adaptation

There have been numerous adaptive behavioural traits found in Great Pond Snails. They grow larger in size in bigger ponds. When the ponds become icy or when these creatures move into deep water, they tend to inhale oxygen through their skin.

Mating

Lymnaea stagnalis reproduces as a hermaphrodite that is playing both male and female roles. A single copulation can have only one sexual role each timeto be performed. Sexual roles can be swapped after completion of each performance.

Reproduction

These creatures lay large-sized eggs that are gelatinous in form. Usually the eggs are laid on weeds and other pond objects. Egg masses are somewhere between 5 to 6 cm long and they contain about 50 to 120 eggs.

Picture 3 – Lymnaea stagnalis Eggs

Life Span

Some records suggest these animals reaching 6 or 7 years of age. However, very few of them tend to reach this age.

Sub-species

There are some subspecies of these creatures. Lymnaea stagnalis jugularis is one of the major subspecies of Great Pond Snail.

Lymnaea stagnalis as Pets

These invertebrates are often stored in aquariums. These snails are harmful in nature but still they make a great aquarium choice.

Care

They should not be brought near fishes and other snails. They can have lettuce and algae wafers while residing in an aquarium. The tanks must be cleaned every 3 weeks for better survival of the Great Pond Snails.

Conservation Status

The species has got a ‘Least Concern’ tag by the IUCN.

Interesting Facts

Here are few interesting facts to know about the snail.

• They have lungs that are able to inhale and exhale oxygen in large amounts.
• They breathe oxygen through skin when there is ice or they go down to live in deep waters.
• They eat small-sized great pond snails as they often act as cannibals.
• They vary in size depending on the water volume. Larger species are found in large ponds.
• They can perform both female and male roles in mating.
• Immature and young species have shells that are more translucent than the adults.
• The wide and flattened tentacles form an integral part of oxygen absorbing role in the snails. A hairy form covers the surface area of the tentacles, thus increasing the ability to inhale more air.

Pictures

Here are a few pictures of the great pond snail.

Picture 4 – Lymnaea stagnalis Photo

Picture 5 – Lymnaea stagnalis Picture