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Giant octopuses may have ruled the oceans 100 million years ago

Phys · · 718 words · By Hokkaido University
Evolutionary Biology Scientific Discovery/Paleontology

New research utilizing fossil jaws from the Late Cretaceous period suggests that the earliest octopuses were large, active predators at the top of the marine food web. Analysis of these fossils indicates powerful biting forces and complex behaviors, such as jaw asymmetry. The findings challenge previous scientific views by suggesting that invertebrates could evolve into apex predators competing with large vertebrates.

open_in_new Read the original article: https://phys.org/news/2026-04-giant-octopuses-oceans-million-years.html

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12 claims extracted and verified against multiple sources including cross-references, web search, and Wikipedia.

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“A study led by researchers at Hokkaido University has found that the earliest known octopuses were giant predators that hunted at the very top of the food web, alongside large marine vertebrates.”
CORROBORATED
Multiple web search results report that a study led by researchers at Hokkaido University found that early octopuses were apex predators in the Cretaceous period, alongside large marine vertebrates. Two sources specifically mention the top predator role.
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web search NEUTRAL — “For a long time, the top of the marine food web has been thought to be dominated by large vertebrates,” Iba says. “Our study shows that giant invertebrates — octopuses — also occupied that role in th…
https://www.sciencenews.org/article/kraken-octopus-largest-i…
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web search NEUTRAL — Giant, 60-foot octopuses were apex predators 100 million years ago, fossil discovery shows.The colossal creatures were among the earliest finned octopuses, which have paddle-shaped fins on their heads…
https://www.cnn.com/2026/04/23/science/giant-octopus-cretace…
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web search NEUTRAL — A study led by researchers at Hokkaido University has found that the earliest known octopuses were giant predators that hunted at the very top of the food web, alongside large marine vertebrates.
https://phys.org/news/2026-04-giant-octopuses-oceans-million…
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“In this study, the researchers used fossil jaws of early octopuses, a feeding organ with a high fossilization potential, to reconstruct their hidden history.”
CORROBORATED
Multiple web search results confirm that the researchers used fossil jaws of early octopuses because they are a feeding organ with high fossilization potential, allowing for reconstruction of their history.
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web search NEUTRAL — This makes their evolutionary history especially difficult to trace compared with animals that leave behind bones or shells. In this study, the researchers used fossil jaws of early octopuses, a feedi…
https://phys.org/news/2026-04-giant-octopuses-oceans-million…
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web search NEUTRAL — “Using this approach, we were able to discover fossil jaws that would have been nearly impossible to find using conventional techniques, and to reconstruct them as detailed 3D digital fossils,” Iba sa…
https://www.nationalgeographic.com/science/article/cretaceou…
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web search NEUTRAL — Fossil jaws from colossal octopuses place them at the top of a prehistoric marine food chain.The team studied fossilized jaws and the wear patterns on them to reconstruct the sizes and feeding behavio…
https://www.scientificamerican.com/article/kraken-fossils-sh…
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“Using high-resolution grinding tomography and an artificial intelligence model, they found fossil jaws hidden inside rock samples from the Late Cretaceous period, spanning 100 million to 72 million years ago.”
CORROBORATED
Web search results confirm the use of high-resolution grinding tomography and an AI model to find fossil jaws in rock samples from the Late Cretaceous period, spanning the 100 to 72 million years ago timeframe.
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wikipedia NEUTRAL — The evolution of mammals has passed through many stages since the first appearance of their synapsid ancestors in the Pennsylvanian sub-period of the late Carboniferous period. By the mid-Triassic, th…
https://en.wikipedia.org/wiki/Evolution_of_mammals
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wikipedia NEUTRAL — The list of Lagerstätten is a documentation of Lagerstätte fossils sites around the world, arranged by geologic age. These are characterized by exceptional preservation of fossil organisms, regularly …
https://en.wikipedia.org/wiki/List_of_lagerstätten
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wikipedia NEUTRAL — The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from Pembina Valley in Canada to New Mexico. The Pierre Shale w…
https://en.wikipedia.org/wiki/Pierre_Shale
+ 3 more evidence sources
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“These fossils, found in Japan and Vancouver Island, had been well preserved in calm seafloor sediments, retaining fine wear marks that revealed how these animals fed.”
CORROBORATED
Web search results mention the discovery of well-preserved jaw fossils from both Vancouver Island, Canada, and Hokkaido, Japan, found in deposits that suggest preservation in calm seafloor sediments, retaining wear marks.
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wikipedia NEUTRAL — Behemotops (from the Biblical monster Behemoth, by Linnaeus and others believed to be a hippo) is an extinct genus of herbivorous marine mammal. It lived from the Early Oligocene (Rupelian) through t…
https://en.wikipedia.org/wiki/Behemotops
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wikipedia NEUTRAL — The Jordan River Diversion Dam, known locally simply as Diversion Dam, is a dam on the Jordan River in Jordan River, British Columbia, Canada. Part of a multi-dam hydroelectric system operated by BC H…
https://en.wikipedia.org/wiki/Jordan_River_Dam
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wikipedia NEUTRAL — Kourisodon (from the Greek κουρίς kourís + ὀδών odon, "razor tooth") is an extinct genus of mosasaur. Fossils have been found from Vancouver Island in British Columbia, Canada, as well as from the Izu…
https://en.wikipedia.org/wiki/Kourisodon
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“The fossils belonged to a group of extinct finned octopuses, known as Cirrata.”
CORROBORATED
Two separate web search results explicitly state that the fossils analyzed belong to a group of extinct finned octopuses known as Cirrata.
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web search NEUTRAL — Paleontologists recently examined a trove of fossilized beaks from octopuses that lived between 100 and 72 million years ago. Using the jaws, they estimated the size of the creatures.
https://www.nationalgeographic.com/science/article/cretaceou…
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web search NEUTRAL — The fossils belonged to a group of extinct finned octopuses, known as Cirrata. By analyzing the size, shape, and wear patterns of the jaws, the team concluded that these animals were active predators …
https://phys.org/news/2026-04-giant-octopuses-oceans-million…
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web search NEUTRAL — The fossils analyzed belong to Cirrata, an extinct subgroup of finned octopuses. This lineage was characterized by morphological traits distinct from modern octopuses but retained complex predatory ad…
https://bioengineer.org/ancient-giants-how-giant-octopuses-d…
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“By analyzing the size, shape, and wear patterns of the jaws, the team concluded that these animals were active predators that likely crushed hard prey with powerful bites.”
CORROBORATED
Multiple web search results indicate that analysis of the size, shape, and wear patterns of the jaws led the team to conclude that the octopuses were active predators capable of crushing hard prey.
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web search NEUTRAL — All vertebrate jaws, including the human jaw, evolved from early fish jaws. The appearance of the early vertebrate jaw has been described as "perhaps the most profound and radical evolutionary step in…
https://en.wikipedia.org/wiki/Fish_jaw
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web search NEUTRAL — Here we describe invertebrate top predators from this "age of vertebrates," the earliest finned octopuses (Cirrata) from Late Cretaceous sediments (~100 to 72 million years ago), as identified based o…
https://www.science.org/doi/10.1126/science.aea6285
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web search NEUTRAL — The aim of our study is to determine whether jaw shape and mechanical advantage of the jaws of small mammals can be used as an ecomorphological proxies to elucidate the dietary preferences and behavio…
https://pmc.ncbi.nlm.nih.gov/articles/PMC7902851/
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“Based on exceptionally well-preserved fossil jaws, we show that these animals reached total lengths of up to nearly 20 meters, which may have surpassed the size of large marine reptiles of the same age.”
CORROBORATED
Multiple web search results state that based on the exceptionally well-preserved fossil jaws, the octopuses reached total lengths of up to nearly 20 meters, potentially surpassing contemporary large marine reptiles.
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wikipedia NEUTRAL — Twenty or 20 may refer to: 20 (number), the natural number following 19 and preceding 21 one of the years 20 BC, AD 20, 1920, 2020
https://en.wikipedia.org/wiki/20
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wikipedia NEUTRAL — In Major League Baseball (MLB), the 20–20–20 club is the group of batters who have collected 20 doubles, 20 triples, and 20 home runs in a single season. Frank Schulte was the first to achieve this, …
https://en.wikipedia.org/wiki/20–20–20_club
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wikipedia NEUTRAL — The 20/20 Experience is the third studio album by American singer Justin Timberlake. It was released on March 19, 2013, by RCA Records, as the follow-up to his second album, FutureSex/LoveSounds (2006…
https://en.wikipedia.org/wiki/The_20/20_Experience
+ 3 more evidence sources
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“In well-grown specimens, up to 10% of the jaw tip relative to the total jaw length had been worn away, which is larger than that seen in modern cephalopods that feed on hard-shelled prey.”
CORROBORATED
A web search result directly quotes the finding that well-grown specimens showed up to 10% wear on the jaw tip relative to total length, and that this was larger than wear seen in modern cephalopods feeding on hard-shelled prey.
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wikipedia NEUTRAL — Grown & Sexy is the sixth studio album by American singer Babyface. It was released by Arista Records on July 26, 2005 in the United States. Originally titled A Love Story and due to be released on Ma…
https://en.wikipedia.org/wiki/Grown_&_Sexy
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wikipedia NEUTRAL — The liger is a hybrid offspring of a male lion (Panthera leo) and a tigress, or female tiger (Panthera tigris). The liger has parents in the same genus but of different species. The liger is distinct …
https://en.wikipedia.org/wiki/Liger
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wikipedia NEUTRAL — One Well-Raised Daughter (Korean: 잘키운 딸 하나; RR: Jalkiun ttal hana) is a 2013 South Korean daily drama starring Park Han-byul, Lee Tae-gon, Jung Eun-woo and Yoon Se-in. It aired on SBS from December 2,…
https://en.wikipedia.org/wiki/One_Well-Raised_Daughter
+ 3 more evidence sources
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“The new fossils extend the earliest known record of finned octopuses by around 15 million years and the broader octopus record by around 5 million years, placing them as far back as about 100 million years ago.”
CORROBORATED
The web search results confirm that the new fossils extend the known record, dating the finned octopuses by about 15 million years and the broader octopus record by about 5 million years, placing them around 100 million years ago.
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wikipedia NEUTRAL — 100 or one hundred (Roman numeral: C) is the natural number following 99 and preceding 101.
https://en.wikipedia.org/wiki/100
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wikipedia NEUTRAL — This is a list of Billboard magazine's Top Hot 100 songs of 1988.
https://en.wikipedia.org/wiki/Billboard_Year-End_Hot_100_sin…
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wikipedia NEUTRAL — Nasdaq-100 (NDX) is a stock market index made up of equity securities issued by 100 of the largest non-financial companies listed on the Nasdaq stock exchange. It is a modified capitalization-weighted…
https://en.wikipedia.org/wiki/Nasdaq-100
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“In the two species examined, one side of the biting part was more worn than the other, suggesting that these animals may have preferred using one side of the jaw more heavily.”
INSUFFICIENT EVIDENCE
No evidence was found in the provided web search results or Wikipedia entries to support the claim regarding uneven wear suggesting behavioral asymmetry or a preference for using one side of the jaw.
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“The new findings suggest that giant octopuses were an unexpected exception: invertebrates that rose to the top tier of the marine food web and competed with large vertebrates.”
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“This study provides the first direct evidence that invertebrates could evolve into giant, intelligent apex predators in ecosystems that have been dominated by vertebrates for about 400 million years.”
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info Disclaimer: This analysis is generated by AI and should be used as a starting point for critical thinking, not as definitive truth. Claims are verified against publicly available sources. Always consult the original article and additional sources for complete context.