Révélations sur Le Monde de Némo : le cannibalisme intra-utérin

09.10.2015 | par Loïc Mangin | Articles & Billets

En 2003 sortait l’un des dessins animés Pixar qui a eu le plus de succès, Le Monde de Némo. La bande-annonce pour les nostalgiques :

Et l’on nous prépare la suite, Le Monde de Dory, (l’histoire du chirurgien bleu Paracanthurus hepatus à la mémoire défaillante) qui sera sur nos écrans le 29 juin 2016. Succès mérité, certes, mais sans doute pas en raison de son réalisme zoologique, nous en avons parlé ici. Pour rappel, le vrai destin de Némo aurait dû être l’inceste transgenre ou l’infanticide par son père. Il a peut-être eu de la chance d’être enlevé par un plongeur

Aujourd’hui, nous allons nous attarder sur quelques-uns des personnages remarquables du film, les trois requins végétariens.

Certains ont des pratiques, comment dire… vous verrez par vous-mêmes comment les définir. D’abord, voyons de quelles espèces sont les trois membres des Mangeurs de Poissons Anonymes.

Bruce est un grand requin blanc Carcharodon carcharias. Selon la légende, Bruce était le nom que donnait Steven Spielberg au requin mécanique utilisé lors du tournage des Dents de la mer.

Bruce © Pixar

Bruce © Pixar

Un grand requin blanc Carcharodon carcharias. © P. Kobeh.

Un grand requin blanc Carcharodon carcharias. © P. Kobeh.

Chumy est un requin mako Isurus oxyrinchus, ou requin taupe.

Chumy © Pixar

Chumy © Pixar

Un requin mako Isurus oxyrinchus . © © M. Conlin, SWFSC Large Pelagics Program

Un requin mako Isurus oxyrinchus . © © M. Conlin, SWFSC Large Pelagics Program

Et enfin, Enclume est un… requin marteau Sphyrna mokarran.

Enclume © Pixar

Enclume © Pixar

Un requin marteau Sphyrna mokarran . © C.J. Crooks

Un requin marteau Sphyrna mokarran . © C.J. Crooks

Ici, c’est leur mode de reproduction qui va nous intéresser. Et là, c’est le bazar…

Au début, tout est simple. Chez toutes les espèces, la fécondation est interne, le mâle introduisant ses spermatozoïdes à l'intérieur de la femelle. Simple ? Enfin, presque, car les requins ont deux pénis, ou plutôt des ptérygopodes. Ces organes résultent de la mutation de la nageoire pelvienne en un tuyau articulé pouvant être muni d'une épine. De leur côté, les femelles ont deux utérus.

Un requin mâle, à gauche, reconnaissable à ses deux ptérygopodes (dans l’ellipse rouge) et une femelle, à droite. © NOAA.

Un requin mâle, à gauche, reconnaissable à ses deux ptérygopodes (dans l’ellipse rouge) et une femelle, à droite. © NOAA.

Peut-on alors déterminer le sexe de Bruce, Chumy et Enclume ? Oui, et en image !

Qui est un mâle ? Qui est une femelle ? © Pixar/Cooney

Qui est un mâle ? Qui est une femelle ? © Pixar/Cooney

Après l’accouplement et la fécondation, toutes les combinaisons sont possibles. Certaines espèces sont ovipares, c’est-à-dire qu’elles pondent des œufs, le plus souvent dans des endroits calmes.

Un œuf de requin dormeur cornu Heterodontus francisci.

Un œuf de requin dormeur cornu Heterodontus francisci.

Un œuf de requin de Port Jackson Heterodontus portusjacksoni. © K. Bunke

Un œuf de requin de Port Jackson Heterodontus portusjacksoni. © K. Bunke

09- Un œuf de la petite roussette Scyliorhinus canicula. © Sander van der Wel

09- Un œuf de la petite roussette Scyliorhinus canicula. © Sander van der Wel

La plupart des requins sont vivipares : les œufs se développent dans l’utérus et les petits sont libérés au moment de l’éclosion. Dans deux familles, les Carcharinidae et les Sphyrnidae, le requin marteau Enclume faisant partie de cette dernière, une sorte de placenta se met en place qui permet aux jeunes d’être nourris par leur mère : ce sont presque des mammifères !

Plus étonnant, on a montré que plusieurs naissances de requin-marteau, par exemple dans un zoo du Nebraska aux États-Unis, résultaient d’une parthénogenèse, c’est-à-dire que l’ovule s’est développé sans fécondation par un spermatozoïde !

Enfin, quelques espèces sont ovovivipares. Les embryons se développent dans les œufs à l'intérieur des voies génitales femelles où ils éclosent, mais ils y restent jusqu’à leur naissance proprement dite. Leur subsistance est assurée par les réserves d’un organe particulier, le vitellus. C’est le cas du grand requin blanc (Bruce) et du mako (Chumy), mais aussi du requin taureau, du requin taupe…

Là où l’affaire se corse et tourne au cauchemar, c’est que dans le ventre de leur mère, les petits requins ne sont pas à l’abri de tout danger… ils sont menacés par leurs propres frères et sœurs. Plus précisément, le premier des petits requins qui éclot dans un des utérus dévore les embryons de ses frères et sœurs voisins pour mieux grandir. En fin de compte, un seul requin plus gros et plus fort naît de chaque utérus.

Un bébé requin taureau Carcharias taurus nouveau-né (H) un embryon (E) dans le même utérus. © D. Chapman/Biology Letters

Un bébé requin taureau Carcharias taurus nouveau-né (H) et un embryon (E) prélevés dans le même utérus. © D. Chapman/Biology Letters

Les embryons sont déjà bien équipés en dents pour dévorer leur fratrie ! © Nat. Geo. Wild

Les embryons sont déjà bien équipés en dents pour dévorer leur fratrie ! © Nat. Geo. Wild

D’ailleurs, c’est bien plus parlant en vidéo ! Voir un embryon de requin croquer ses frères et sœurs, ça ne va pas aider à améliorer la réputation des squales !

Cette pratique de cannibalisme intra-utérin est nommée l’adelphophagie. Lorsque ce sont les œufs qui servent de repas, on parle d'oophagie. J’espère que le scénario du Monde de Dory tiendra compte de ce comportement, ce sera du meilleur effet avec une réplique du genre : « Les poissons sont nos amis on y touche plus ! Mon frère m’est resté sur l’estomac. » Après les dents de la mère, les dents du frangin !

Pour en savoir plus.


57 commentaires pour “Révélations sur Le Monde de Némo : le cannibalisme intra-utérin”

  1. Bruno Répondre | Permalink

    euh ... petite nuance: la consommation des embryons dans les voies génitales, c'est l'adelphophagie, donc des embryons et oeufs en cours de développement

    l'oophagie, c'est la consommation des oeufs/ovules, fécondés ou pas

    les deux cas existent chez les requins

  2. office.com/setup Répondre | Permalink

    I am really very happy to visit your blog. Now I am found which I actually want. Thanks a lot for sharing a piece of wonderful information which I am looking for a longer period of time.

  3. Mcafee.com/activate Répondre | Permalink

    I just wanted to say that I love every time visiting your wonderful post! Very powerful and have true and fresh information. Thanks for the post and effort! Please keep sharing more such a blog.

  4. Norton.com/setup Répondre | Permalink

    This is really an amazing article.Thanks a lot for sharing a piece of wonderful information keep it up and best of luck for your future article and posts.

  5. Mcafee.com/activate Répondre | Permalink

    Thank you for sharing your info. I really appreciate your efforts and Thanks a lot for sharing a piece of wonderful information which I am looking for a longer period of time.

  6. Mcafee.com/activate Répondre | Permalink

    It’s truly a great and useful piece of info. I’m happy that you just shared this useful information with us. Please keep us up to date like this. Thanks for sharing.

  7. McAfee vs Norton Répondre | Permalink

    It’s truly a great and useful piece of info. I’m happy that you just shared this useful information with us. Please keep us up to date like this. Thanks for sharing.

  8. Cash app create account Répondre | Permalink

    I am very enjoyed for this blog. It's an informative topic. It helps me very much to solve some problems. Thanks for the valuable information and insights you have so provided here.

  9. Block emails on AOL Mail Répondre | Permalink

    I really impressed after read this because of some quality work and informative thoughts. I just wanna say thanks to the writer and wish you all the best for coming!.

  10. McAfee Removal Tool Répondre | Permalink

    Wonderful article, thanks for putting this together! This is obviously one great post. Thanks for the kindness in sharing your expertise with us.

  11. Lucy jhonson Répondre | Permalink

    I really enjoy this blog which is on fish, it's extremely and informative keep it up
    Mcafee antivirus is one of the best to keep your device safe and secure weather PC laptop or smartphones it's free to use and easy to handle.
    Install McAfee Total Protection [url = https://e-mcafee.com install-mcafee-total-protection/]McAfee Total Protection[/url]

  12. Norton Login Répondre | Permalink

    Enjoyed reading the blog, it is very interesting.Thank you and good luck for the upcoming blogs.

  13. AOL Mail Répondre | Permalink

    Very interesting blog, good work and thanks for sharing such a good post. Keep posting such blogs.

  14. Sbcglobal Login Répondre | Permalink

    Found your post interesting to read. This article is really very captivating. I can't wait to see your post soon. Good Luck for the upcoming posts.

  15. travel tips Répondre | Permalink

    Very interesting blog, good work and thanks for sharing such a good post. Keep posting such blogs.

  16. Apple airport router Répondre | Permalink

    To make a soft reset to your Apple airport router, you need to press and hold the reset button for 1 second and then release the button. From the Wi-Fi status menu, choose the Wi-Fi network and open AirPort Utility, then click from the pop-up menu. You can now change the password or reconfigure the base station as needed. Finally, click Update to save settings.

  17. sparklesflippant Répondre | Permalink

    The vast majority of bank accounts in France will require an initial financial outlay to secure account opening. This value differs from bank to bank and also depends on variable rates of currency exchange. An international finance expert will help to navigate these conversions as well as the assorted fees and minimums involved in sustaining a bank account. Be sure to understand interest and growth rates associated with any potential international bank account so that you are able to maximize your earnings while minimizing risk.

  18. Cash App bank account Répondre | Permalink

    If you haven’t added your debit card details during the Cash App sign-up process, you will need to link a bank account later on in order to process any transactions via Cash App. To link a Cash App bank account, you should go to the “Banking” tab on the main screen and choose “Link Bank.” After this, you need to provide your debit card details and you’re done.

  19. Brother Printer offline error Répondre | Permalink

    While using your Brother printing machine, you may come across different errors and one such error is the offline error. However, to fix the Brother Printer offline error you do not need to input much effort. Just check the network connectivity and also check if your printer is set as the default printer or not. Else, try to disable the offline usage feature.

  20. QuickBooks online desktop app not working Répondre | Permalink

    If the desktop application of QuickBooks does not open or hangs on your pc, then the most common reason for the same is an outdated app. To fix QuickBooks online desktop app not working issue, reinstall the app or clear the cache and browser cookies from your device. You can also check that your desktop is connected to a network or not to make sure the app works fine.

  21. reset Bellsouth email password Répondre | Permalink

    While entering your password on the Bellsouth login page, you may see an incorrect password error. Thus, to reset Bellsouth email password, tap on the “Forgot password” link and complete the identity verification process. After this, you will be provided with the reset link on which you have to click and follow the prompts to set a new Bellsouth email password.

  22. Lily Acer Répondre | Permalink

    Nice post. If you have any issue regarding Norton Antivirus error visit this website.

  23. Godox Répondre | Permalink

    thank you for sharing this post I am glad to be here and read this post is really make my day thanks

  24. Traunch Répondre | Permalink

    The investor will make money in two ways from a deal like this. First, the profit made from the sale of one of many bonds will be divided into portions or parts of a single large bond. Second, the value of this single large bond will increase over time, allowing you to earn a nice return on your initial investment while the company makes its profits. In this way, a good portion of your initial investment will be returned to you as a result of Traunch.

  25. What are the metalloids Répondre | Permalink

    What are the metalloids? When you are a student of science or engineering and you want to know what are the metalloids, you will need to learn what all the different types of metalloids are and what they are made of. You will find that there are many different types of metalloids and all the different types have their own characteristics as well as properties. Some of these metalloids include iron, tin, aluminum, magnesium, boron, phosphorus, silicon, mercury, ruthenium, bromine, sulfur and manganese all of which have different physical, chemical and electrical properties depending on what is in which they are mixed with other materials.

  26. What does shorting a stock mean Répondre | Permalink

    What does shorting a stock mean? If you are new to trading or simply looking to diversify your portfolio, then you need to know what does shorting a stock mean. In Forex trading, shorting a stock is buying the stock at its current low and selling it for a profit before the price goes down any lower. Many new traders get into the market with this concept in mind, only to find that they lose their money quickly and without diversification. This article will discuss shorting a stock, the reasons why it is bad to short a stock, and how to become a successful short seller instead of a short buyer.

  27. How much does twitch streamers make Répondre | Permalink

    How much does twitch streamers make? When a twitch user gets started they do not want to make a lot of money right away. Instead, they want to work their way up the ladder of success. Once they have built up a decent amount of followers they can then look to monetize their account. Many individuals use this method as a means of teaching aspiring swifiers how to make a living off of something that they actually enjoy. There are many options available to those that are interested in becoming streamers, so make sure that you take your time deciding which option is best for you!

  28. What does cc mean in email Répondre | Permalink

    In effect, the CC field in an email allows the sender to send a “carbon copy” of the email to someone apart from the recipient in the To: field of the email. The CC field in email lets you keep recipients in the loop.

  29. What is short selling Répondre | Permalink

    What is short selling? It is a process of selling a stock through a broker or dealer that purchases the stock for less than you paid. The reason that you are selling your stock for less than you paid is because the price of the stock has dropped to less than what you paid. What is short selling to a broker is that they make a profit by buying the stock at this price and then selling it to you for a higher price. You do not actually get a "short" trade, but instead you are buying stock from another company at a price that is a bit more than you paid.

  30. Tiffin service Répondre | Permalink

    Are you looking for tiffin service? Maas Best provides the high quality of tiffin service delivery at affordable prices to his customers. Maas Best is one of best tiffin service provider where provides the indian tiffin service london delivery in the United Kingdom. You can now order food online, all your favourite dishes, and many more delicious options.

  31. tiffin service near me Répondre | Permalink

    Are you looking for tiffin service near me. Maas Best provides the high quality of tiffin service at affordable prices to his customers. Maas Best is one of best tiffin service provider where provides the tiffin service near me, Indian tiffin service, and tiffin food delivery in the United Kingdom. You can now order food online, all your favourite dishes, and many more delicious options.

  32. indian food near me Répondre | Permalink

    Are you looking for indian food near me? Maas Best provides the high quality of indian food, tiffin home delivery, and Indian tiffin delivery at affordable prices to his customers. Maas Best is one of best tiffin service provider where provides the home-cooked Indian food, Indian tiffin service, and tiffin food delivery in the United Kingdom. You can now order food online, all your favourite dishes, and many more delicious options.

  33. www.mcafee.com/activate Répondre | Permalink

    McAfee.com/activate is a Multinational American multinational computer security software company offering threat intelligence, endpoint protection, and security information services.

  34. www norton com setup Répondre | Permalink

    Norton is a leading antivirus software company that has been around for over 30 years. Norton provides a 24/7 support team that’s available to assist customers with security and technical issues. Additionally, they have a live chat feature that allows users to communicate with the technicians during off-hours as well as an online chat platform.

    Norton Security Setup is a comprehensive security platform that helps you protect your desktop or mobile device from viruses, hackers, spyware and other threats. When it comes to improving your device's security settings, Norton Security Setup can be a valuable tool for helping prevent a phishing website from stealing your personal information and passwords.

    Norton offers free tools such as Norton Safe Connect, which provides secure communication over VPN and Norton Identity Safe, which helps you create strong passwords and keep your identity confidential.

    Norton.com/setup Activate is a feature that allows people to activate their Norton subscription automatically after a certain period of time. This way it becomes a renewable subscription, not requiring the user to renew every year.

    This feature is designed for people who can't remember to renew their subscription on time. The automatic renewal also means that you'll continue to be protected from malware and hackers.

    Norton provides 8 important tips to help customers protect their electronics and avoid getting hacked. These include:

    1. Smartphones need to be updated

    2. Keep your laptop powered off when not in use

    3. Keep your anti-virus software up to date

    4. Enable two-factor authentication on all your accounts that support it

    5. Use data encryption

    6. If you’re unsure about whether an app is safe, look for reviews online

    7. Keep your mobile device firmware up to date

    8. Only install apps from trusted sources like the app store

    Norton activation hacks are not just limited to the Norton products. They also work with other software products that are classified as “single-use”.

    Norton activation hacks are used to provide better value by offering a discount for the first time use of the product. It is important to note that these activations usually require a unique code that can be found in the user manual or product packaging.

    www norton com setup is designed to work with other antivirus software that you already use.

    This setup provides protection for your computer against any threats that might exist on the web, but it does not replace your existing antivirus software.

    Company's Norton Security Suite combines three of the most powerful security tools - antivirus, firewall, and spyware protection - in one product for PC users.

  35. Kale Johnson Répondre | Permalink

    To learn how to connect Canon Printer to computer by following simple steps. Firstly, you need to complete the physical connection process using a USB cable. Then, you need to add your printer to the computer. For this, you need to go to Devices and Printers option from Hardware and Sound menu. Go to Add a printer option and then select local printer. Choose Canon printer from available printer options. Now, you can set your Canon printer as the default printer if you like.

  36. Canon.com/ijsetup/mg2522 Répondre | Permalink

    Canon Pixma MG 2522 inkjet printer is a wireless printer available with a 4-Color Cartridge Hybrid Ink System in XL that will see a less of replacement.

  37. Microsoft 365/setup Répondre | Permalink

    Sign in with Microsoft 365 login account if you already are using Microsoft’s other services like Outlookcom, Xbox Live, Skype, or OneDrive, it means you can use this account for Microsoft Office 365 login.

  38. ij.start.canon Répondre | Permalink

    It allows you to download, install, and configure canon ij setup on your PC, Mac and smartphones as well. Canon ij setup is the software to install Canon printer wirelessly.

  39. http://ij.start.canon Répondre | Permalink

    The wireless and wired models require drivers and software; therefore, each has to undergo one important installation process. If your printer model isn’t set up yet, you can get started now.

  40. ij.start.canon Répondre | Permalink

    ij.start canon is the manufacturer site to download Canon printer drivers. Install and set up Canon Printer from https: //ij.start.canon and obtain high-quality printing documents straightforwardly.

  41. Canon IJ Network Tool Répondre | Permalink

    Canon IJ Network Tool is a toolkit software with the options to keep a check on most of your Canon printer network settings and adjust them according to your requirements.

  42. Canon IJ Printer Utility Répondre | Permalink

    Canon IJ Printer Utility is a complete software package meant to adjust and modify the configurations of your printer device as per the requirement. It is one of the essential utility software offered by Canon to ease your printer configuration alteration using a few clicks.

  43. My CC Pay Répondre | Permalink

    Young Investigators’ Meeting brings together an eclectic mix of India’s bestearly-career life science researchers, postdoctoralfellows, reputedIndian and international scientists,administrators of institutions, funding agencyrepresentatives and science policy makers for 5 daysof discussions and interactions focusing on scienceand careers in science.

Publier un commentaire