Escargot géant solitaire ou grégaire?

Giant African Snails : Solitary or Gregarious ?

Giant African Snails: Solitary or Gregarious?

Following numerous debates and controversies on this topic, it is legitimate to ask the question: “Are giant African snails solitary or gregarious?” Many keepers have wondered, and a great deal can be read on the subject without any supporting evidence. “I’ve observed that they do better in pairs.” “My snail has been less active since being alone.” “Would you enjoy spending your life alone?” “A snail is clearly solitary.” “My snail has been thriving since it was separated.” It is important to remember that in science, observations are valuable for forming hypotheses, but they are by no means proof.

So what is the reality? To answer this question, we will first look at the definitions of these terms, review what current studies say, discuss how to set up a proper housing arrangement, explore observed behaviours, and then draw an initial conclusion.

I would like to remind you that in science, nothing is set in stone, nothing is definitively proven. We can only support or challenge a hypothesis under very specific given circumstances. We will do our best to answer this question using the tools available to us.

Solitary, Gregarious — What Do These Actually Mean?

What is a solitary or gregarious species? Let’s start with the definitions:

Gregarious (adjective): Relating to animals that live in groups without necessarily having a highly developed social organisation.

Solitary (adjective): Living alone, in isolation.

Another term that comes up regularly is aggregate:

Aggregate (noun): A gathering of a large number of heterogeneous elements.

In animal behaviour, we speak of an aggregate when a solitary species gathers in the same place either:

  • For protection (strength in numbers!)
  • Because survival conditions are ideal (food, temperature, etc.)
  • Due to overpopulation

What Do the Studies Say?

First Study

According to Fischer M. et al. — 2012, snails of the species A. fulica (Lissachatina fulica according to Mead — 1994) are gregarious in their juvenile stage (hatchlings), particularly at night, as a strategy to reduce predation and increase survival rates. The grouping of newly hatched snails is referred to as a naissain (brood). However, adults prefer isolation and tend toward a solitary life.

“The sample consisted of 3,623 specimens that had shown a preference for isolation, illustrating the fact that aggregation is not a set pattern for this species, but rather a strategy that varies depending on the site, the season, the maturity of the animal and the substrate. This suggests that there is a link between aggregation and factors such as protection, reproduction and overpopulation.” — Fischer M. et al. — 2012

The fact that snails group together in our terrariums would therefore be, according to this study, merely a strategy in response to a problem arising from either husbandry conditions, overpopulation, a perceived threat, or the drive to reproduce. It is worth remembering that this is a highly invasive species, capable of behavioural adaptability in order to reproduce as prolifically as possible. It does not in any way reflect boredom or any other form of anthropomorphism. Let us not forget that a wild or non-domesticated animal — such as our giant snails — operates with species survival as its primary drive.

This study was conducted on both free-ranging and terrarium-kept animals.

The University of Michigan Museum of Zoology

According to the University of Michigan Museum of Zoology, A. fulica is solitary and does not influence the behaviour of its offspring.

“Achatina fulica is a solitary species. The parents do not have an impact in their offsprings’ lives once the eggs are hatched, so the solitary behavior is intact from the beginning.” — https://animaldiversity.org/accounts/Achatina_fulica/

A Note on Territorial Competition and Interspecies Pressure

Some keepers believe that housing two snails of different species together would resolve issues of territorial competition and unwanted breeding.

To date, nothing has proven the existence of self-fertilisation or parthenogenesis, although the presence of the ovotestis does seem to suggest a possibility — though this information has been disputed. Furthermore, some keepers have encountered this very situation, which leads us to say that keeping an individual alone does not guarantee the absence of egg-laying.

Additionally, hybridisation is entirely possible between certain species.

Territorial competition between two species can cause stress and therefore distress. One may dominate the other. One only needs to look at the wild, where Archachatina bicarinata is endangered due to invasion by Archachatina marginata. You can support the Forest Giants project.

Setting Up a Proper Housing Arrangement

Ideally, for a breeding setup, you would want a terrarium large enough to accommodate the individual territories and living space of two snails. The question is: what floor space does a snail actually need?

If we take data from commercial farming into account, the estimates are as follows per square metre (10,000 cm²):

  • 200 individuals at 25g → 50 cm²/individual
  • 100 individuals at 50g → 100 cm²/individual
  • 50 individuals at 100g → 200 cm²/individual
  • 25 individuals at 200g → 400 cm²/individual
  • etc.

However, if we refer to petsnails.co.uk, the figures are:

  • For L. fulica: 600 cm² per individual (approx. 12 cm, average weight 100g)
  • For A. marginata: 750 cm² per individual (approx. 15 cm, average weight 400g)

Decoration and dish surfaces should be added to these figures to arrive at the ideal terrarium size. Personally, I account for 1/3 of the terrarium floor area for decorations.

My personal recommendation would be 800 cm² per individual (12 cm / 100g, e.g. L. fulica, L. immaculata) to ensure comfort, and 1,200 cm² per individual for Archachatina / Achatina species.

For example, an Exo Terra 60×45×45 cm terrarium could accommodate 900 cm² of decoration (1/3 of the floor area) and two adult L. fulica / L. immaculata individuals. If you have any doubts about the right terrarium size or equipment to choose, you can consult the beginner’s kit article.

For hobby keeping, I recommend one terrarium per species, ideally housing one individual — and if your floor space is large enough, you may keep two.

Snail Behaviours Explained

Why does my snail seem less active since being on its own?

As we know, the strategy used by giant snails to find a mate is tracking — carried out by detecting chemical signals left in mucus. Snails housed together as adults will constantly be searching for a sexual partner, spending their time pursuing one another. According to the University of Michigan Museum of Zoology, the reproductive period can occur at any time of year. As a result, an animal that suddenly finds itself alone will no longer detect the chemical signals of its companions. It will no longer be driven to track them for reproduction. One might also wonder how it processes this disappearance — could it perceive it as a predator?

Chemical communication between snails should not be underestimated, and it can be taxing for individuals.

Some snails may go into aestivation. Their capacity to adapt to different situations suggests this is not boredom. Also be mindful of husbandry parameters and endogenous rhythms linked to the seasons.

Why is my snail always stuck to its companions?

  • It may indicate an area perceived as ideal — or at least the most suitable spot in the terrarium — in terms of temperature, humidity, pressure, substrate, etc.
  • It may be a grouping strategy in response to feeling threatened — by another species, vibrations, etc. — what we call an aggregate.
  • They may also have grouped together for the purpose of reproduction.

Conclusion: Giant Snails — Solitary or Gregarious?

It is difficult to give a clear-cut answer to the question “Are giant snails solitary or gregarious?”, but we can say that Lissachatina fulica is solitary once adult, although it can adapt by grouping with its companions for survival purposes. In hobby keeping, let us not forget that our responsibility is to provide comfort and wellbeing — not conditions that trigger survival instincts.

The behaviour of hatchlings, however, does follow an aggregate strategy, so it is important to respect the integrity of the brood.

For keepers, I recommend respecting the recommended terrarium sizes for each individual. For hobby keeping, the ideal is one individual per terrarium.

Do not be misled by “I observed that…” — it is easy to observe a behaviour and interpret it through a human lens. But truly understanding an animal is another matter entirely.

A telling example is the Madagascar lemur: videos of these animals being tickled have circulated widely online. Many humans find them cute or funny — but for the lemurs, it is in reality a form of genuine torture.

Stay curious, think critically about information you encounter, and don’t hesitate to question what you know.

If you have additional studies or information on this very controversial topic, I would be delighted to read them and update this article accordingly.

See you soon!

Sources

Definitions:

Studies:

The Forest Giants Project:

Additional Data:

Articles que vous pourriez aimer :

En tête La gestion des pontes et l'oeufIn-Depth Egg-Laying Management: From Beginner to Specialist Escargot géant solitaire ou grégaire?Les escargots géants d’Afrique, Solitaires ou Grégaires?

Published by Kaori

Leave a Reply