Japanese eel, Anguilla japonica
If creationism’s putative intelligent [sic] designer set out to show how stupid it can be, it would be hard pressed to come up with something as bizarre as designing a fish to eat eels, then designing eels to be able to escape from the stomach of the predators designed to eat them.
And yet creationists must believe that's exactly what their hyper-intelligent, omniscient god has done, according to the discovery of a team of researchers from the Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Japan.
According to their report in the Cell Press journal Current Biology, juvenile Japanese eels, Anguilla japonica, can escape from the stomach of the predatory fish Odontobutis obscura by travelling back up the fish's oesophagus and out through a gill slit.
Researchers have shown how juvenile Japanese eels, Anguilla japonica, can escape from the stomach of a predatory fish, Odontobutis obscura* Are there any other examples of prey escaping after being swallowed by predators? Yes, there are several fascinating examples of prey escaping after being swallowed by predators across different species in the animal kingdom. Here are some notable cases:This is not the only example of creationism's putative designer pulling off this stunning example of design stupidity as the AI panel on the right shows.
- Northern Leopard Frog (Lithobates pipiens)
- Predator: Garter snakes (Thamnophis spp.)
- Escape Mechanism: Northern leopard frogs have been observed escaping from the stomachs of garter snakes after being swallowed. The frogs use their legs to kick and push against the snake’s stomach, sometimes managing to force themselves back out through the mouth.
- Asian Swamp Eel (Monopterus albus)
- Predator: Various birds and fish
- Escape Mechanism: Asian swamp eels are known for their slippery bodies and agility. They have been documented escaping from predators, including birds, by wriggling out of the predator's mouth or throat. Their slimy coating and powerful muscles help them squeeze out of tight spaces.
- Horned Lizard (Phrynosoma spp.)
- Predator: Snakes, particularly coachwhip snakes (Masticophis spp.)
- Escape Mechanism: Horned lizards can sometimes escape after being swallowed by using their sharp scales to irritate the predator’s digestive tract. In some cases, they may also inflate their bodies or contort themselves in ways that induce regurgitation.
- Cuttlefish and Octopuses (Various Species)
- Predator: Marine fish
- Escape Mechanism: Some cuttlefish and octopuses have been documented escaping from the stomachs of predators by expelling large amounts of ink or mucus. This can cause confusion or irritation, leading the predator to regurgitate the prey.
- Crucian Carp (Carassius carassius)
- Predator: Pike (Esox lucius)
- Escape Mechanism: Crucian carp have been observed escaping from the stomach of pike by swimming forcefully and leveraging their slippery scales. In some cases, they may also inflate their bodies, making them difficult to swallow and causing the pike to regurgitate.
- Earthworms (Various Species)
- Predator: Birds and other small predators
- Escape Mechanism: Earthworms are known for their ability to survive in extreme conditions. They can sometimes escape from the stomachs of predators, such as birds, by wriggling through the digestive tract or inducing regurgitation by irritating the predator's throat.
- Bombardier Beetles (Brachininae subfamily)
- Predator: Frogs and toads
- Escape Mechanism: Bombardier beetles have a unique defense mechanism where they eject a hot, noxious chemical spray from their abdomens. This can cause severe discomfort to a predator, leading to regurgitation even after the beetle has been swallowed.
These examples highlight the diverse adaptations prey species have evolved to escape predation, even after being ingested.
How the team captured this escape technique is the subject of information made available ahead of publication by Cell Press and reported in ScienceDaily:
How Japanese eels escape from their predator's stomach
Many prey species have defensive tactics to escape being eaten by their would-be predators. But a study in the Cell Press journal Current Biology on September 9, 2024 has taken it to another level by offering the first video evidence of juvenile Japanese eels escaping after being swallowed into the stomachs of their fish predators. With the aid of X-ray videography, they found that the eels back their way out, first inserting the tips of their tails through the esophagus and gills before pulling their heads free.
We have discovered a unique defensive tactic of juvenile Japanese eels using an X-ray video system: they escape from the predator's stomach by moving back up the digestive tract towards the gills after being captured by the predatory fish. This study is the first to observe the behavioral patterns and escape processes of prey within the digestive tract of predators.
Yuuki Kawabata, co-corresponding author
Graduate School of Fisheries and Environmental Sciences
Nagasaki University, Bunkyo, Nagasaki, Japan.
In an earlier study, the researchers including Kawabata and Yuha Hasegawa had shown that Japanese eels can escape from the gill of their predator after capture. What they didn't know was how.
We had no understanding of their escape routes and behavioral patterns during the escape because it occurred inside the predator's body.
Yuha Hasegawa, lead author
Graduate School of Fisheries and Environmental Sciences
Nagasaki University, Bunkyo, Nagasaki, Japan.
In the new study, they found a way to see inside the predatory fish (Odontobutis obscura) using an X-ray videography device. To visualize the eel after it had been eaten, they had to first inject them with a contrast agent. It still took the team a year to capture convincing video evidence showing the escape process involved.
Their videos show that all 32 captured eels had at least part of their bodies swallowed into the stomach of their fish predators. After being swallowed, all but four tried to escape by going back through the digestive tract toward the esophagus and gills, they report. Of those, 13 managed to get their tails out the fish gill, and nine successfully escaped through the gills. On average, it took the escaping eels about 56 seconds to free themselves from the predator's gills.
The most surprising moment in this study was when we observed the first footage of eels escaping by going back up the digestive tract toward the gill of the predatory fish. At the beginning of the experiment, we speculated that eels would escape directly from the predator's mouth to the gill. However, contrary to our expectations, witnessing the eels' desperate escape from the predator's stomach to the gills was truly astonishing for us.
Yuuki Kawabata.
Further study found that, despite the similarities, the eels didn't always rely on the same escape route through the gill cleft. Some of them also circled along the stomach, seemingly in search of a way out. The findings are the first to show that the eel Anguilla japonica can use a specific behavior to escape from the stomach and gill of its predator after being eaten. It's also the first time any study has captured the behaviors of any prey inside the digestive tract of its predator, according to the researchers.
The researchers say that the X-ray methods used in the study can now be applied to observations of other predator-prey behaviors. In future work, they hope to learn more about the characteristics that make for a successful escape by the eels.
SummaryTo make matters worse for creationists, there isn't even an excuse to try the 'Michael J. Behe' apologetic of citing the scientifically nonsensical notion of 'genetic entropy' and 'devolution' [sic] because evolving the ability to escape being digested by a predator is not in any sense of the word detrimental. In fact, this is classic arms race-driven evolved behaviour on the part of the eels, for which the predatory fish has yet to evolve a counter measure. It highlights the different strength of evolutionary selectors where the eel stands to lose its life, whereas the fish stands only to lose a meal.
Predation shapes diversity in the defensive tactics of prey. One specialized defensive tactic is to escape the digestive system of the predator after capture1,2,3,4,5,6,7,8. While most of these defensive tactics involve passive ejection alive from predators’ mouths and vents1,2,3,4,5, active escape from the digestive tracts of predators has recently been observed in certain invertebrate species6,7 and fish8. However, no study has yet uncovered the behavioral patterns and escape routes of the prey within a predator’s digestive tract. Here, we report the sequential escape processes of the Japanese eel Anguilla japonica from capture to escape via the gills of predatory fish Odontobutis obscura using an X-ray video system. All captured eels had at least one portion of their bodies swallowed into the stomach of the predator. Surprisingly, after being swallowed, most individuals attempted to escape by going back up the digestive tract towards the esophagus and gill, and some of them succeeded in escaping via the predator’s gill. Some eels, whose entire bodies were completely inside the stomach, exhibited circling behavior along the stomach, seemingly searching for possible escape routes. An electro-anesthetization experiment revealed that eels utilize various escape routes through gill clefts, rather than just one.
Main text
The experiment was initiated by injecting barium sulfate into the abdominal cavity and tail of A. japonica juveniles (elvers and yellow eels, 68.1 ± 6.0 mm, n = 104) that were reared in laboratory conditions. Subsequently, one A. japonica was introduced into the experimental tank with one O. obscura (145.4 ± 15.6 mm, n = 11) and the predator–prey interactions following capture were recorded using an X-ray video system (see Supplemental information for details of the experimental procedure). Of the 32 individuals captured, 13 (13/32; 40.6%) had their tails emerge from the gill of the predators, and of those, nine (9/13; 69.2%) completed their escape. These results suggest that the period until the tails emerge from the predator’s gill is particularly crucial for successful escape. The behavioral sequence of A. japonica observed within the digestive tract of O. obscura was modeled using the transition probabilities of a Markov chain (Figure 1A).
The most typical behavioral transition observed during the escape process involved initial tail-insertion towards the esophagus, followed by tail escape through the gill, which ultimately concluded with A. japonica pulling its head out from the gill (Figure 1B–D and Video S1). Eleven individuals (11/32; 34.4%, 15 observations) that were completely swallowed into the predator’s stomach exhibited circling behavior along the stomach wall (Figure 1E and Video S2). Five out of the 11 individuals were able to transition to tail-insertion behavior (5/11; 45.4%, 7/15 observations). Two individuals inserted their tails in the direction of the vent rather than toward the esophagus, resulting in failed escape attempts. During the final phase of escape, when most of the body had already emerged, six individuals were observed coiling their bodies in order to extract their remaining head from the predator’s gill, and five of them completed the escape. Many piscivorous fishes swallow the prey headfirst by manipulating them after catching them9. The elongated body of A. japonica would increase the likelihood of the tail remaining in the esophagus when being swallowed by the predator headfirst, which might facilitate their escape.
Figure 1 Escape behavior of Japanese eel A. japonica juveniles through the predator’s digestive tract after being captured.
(A) Behavioral transitions of A. japonica during the escape, determined by Markov chain modeling. The probability of each state transition is calculated from the relative frequency of behavioral changes from the previous state. Consequently, the total probability (indicated by the arrows) extending from one state always amounts to 100%. The width of the lines shows the probability of each transition. The photographs and drawings (B–E) show X-ray images (left) and corresponding sketches (right) of the characteristic behavior during the escape. The red dashed box represents the filming range of the X-ray images. (B) Tail-insertion behavior into the predator’s esophagus using the tip of the tail. (C) Emerging through the predator’s gill. (D) Pulling the head from the predator’s gill by coiling their bodies. (B–D) are in Video S1. (E) Circling along the stomach wall as if searching for possible escape routes from the predator’s stomach. (E) is in Video S2.Many predatory fishes including O. obscura swallow their prey whole with surrounding water by rapidly opening their mouths10. Consequently, the prey is directed into the digestive tract of the predator, where it is killed by the highly acidic and anaerobic environment. Once swallowed into the digestive tract of the predator, A. japonica gradually reduced its activity and ceased all movements (i.e., death) within 211.9 seconds on average. There was a correlation between the duration of activity within the digestive tract and the weight of A. japonica (generalized linear mixed model: df = 1, χ2 = 5.21, p < 0.05). Additionally, there was a significant effect of the body weight of A. japonica on their escape probability (generalized linear mixed model: df = 1, χ2 = 4.26, p < 0.05). Therefore, it is probably essential for eels to develop muscle strength and locomotory performance to quickly escape from an anaerobic and highly acidic environment as well as tolerate such a lethal environment. Further experiments involving prey–predator interactions with various sizes of A. japonica, while measuring their locomotory performance and tolerance to severe environments, are necessary to identify the specific factors that enable successful escape.Video S1. Escaping behavior of Japanese eel Anguilla japonica juveniles through the predator’s digestive tract after being captured
The video on the right is captured by the X-ray video system, while the video on the left is captured by the conventional video camera. The large white area and two black dots represent the air bladder and otolith of O. obscura, respectively. The A. japonica is captured by the predatory fish and swallowed into its stomach (00:13:13-00:30:23). The A. japonica inserts its tail through the esophagus and the gill of the predator (00:14:27-). The tail emerges from the predator’s gill opening (01:10:01). The A. japonica pulls its remaining head from the predator’s gill by coiling its body (01:19:05-01:27:00). The A. japonica completes the escape and swims away from the predator (01:27:01-).
Video S2. Circling behavior of Japanese eel Anguilla japonica along the stomach wall of the predator
Some invertebrates have the ability to escape from the digestive systems of predators by either navigating backward6, similar to eels, or by moving forward towards the vent7. The X-ray method used in our study is applicable for observing the behaviors of these prey inside a predator and identifying the specific organs that pose challenges for their passage. Such knowledge will provide valuable insights into the kinematic, physiological, and behavioral traits that are crucial for successful escapes, thereby offering new insights into the evolution of post-capture anti-predator tactics in prey.
By rejecting the evolution explanation and claiming all this was the work of a single supernatural designer (as if!) creationists are left with claiming this ludicrous state of affairs is the work of an incompetent idiot who couldn't be trusted to design a functional wooden spoon.
The Unintelligent Designer: Refuting The Intelligent Design Hoax
ID is not a problem for science; rather science is a problem for ID. This book shows why. It exposes the fallacy of Intelligent Design by showing that, when examined in detail, biological systems are anything but intelligently designed. They show no signs of a plan and are quite ludicrously complex for whatever can be described as a purpose. The Intelligent Design movement relies on almost total ignorance of biological science and seemingly limitless credulity in its target marks. Its only real appeal appears to be to those who find science too difficult or too much trouble to learn yet want their opinions to be regarded as at least as important as those of scientists and experts in their fields.
Available in Hardcover, Paperback or ebook for Kindle
The Malevolent Designer: Why Nature's God is Not Good
This book presents the reader with multiple examples of why, even if we accept Creationism's putative intelligent designer, any such entity can only be regarded as malevolent, designing ever-more ingenious ways to make life difficult for living things, including humans, for no other reason than the sheer pleasure of doing so. This putative creator has also given other creatures much better things like immune systems, eyesight and ability to regenerate limbs that it could have given to all its creation, including humans, but chose not to. This book will leave creationists with the dilemma of explaining why evolution by natural selection is the only plausible explanation for so many nasty little parasites that doesn't leave their creator looking like an ingenious, sadistic, misanthropic, malevolence finding ever more ways to increase pain and suffering in the world, and not the omnibenevolent, maximally good god that Creationists of all Abrahamic religions believe created everything. As with a previous book by this author, "The Unintelligent Designer: Refuting the Intelligent Design Hoax", this book comprehensively refutes any notion of intelligent design by anything resembling a loving, intelligent and maximally good god. Such evil could not exist in a universe created by such a god. Evil exists, therefore a maximally good, all-knowing, all-loving god does not.
Illustrated by Catherine Webber-Hounslow.
Available in Hardcover, Paperback or ebook for Kindle
Illustrated by Catherine Webber-Hounslow.
No comments :
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.