The Oldest Octopus Was a Giant Apex Predator
A joint research group including Hokkaido University and Morgenrot Inc. utilized an AI model to analyze ancient octopus jaw fossils, revealing they were highly intelligent, 19-meter-long apex predators.
📋 Article Processing Timeline
- 📰 Published: April 24, 2026 at 12:00
- 🔍 Collected: April 24, 2026 at 03:31
- 🤖 AI Analyzed: April 24, 2026 at 03:45 (13 min after Collected)
*This press release is a joint release by Hokkaido University, Osaka Metropolitan University, Niigata University, Chuo University, and Morgenrot Inc.
Points
- Successfully reconstructed detailed ecology by highly visualizing octopus jaw fossils using AI methods and analyzing surface traces.
- Revealed that octopuses from 100 million years ago reached up to 19 m in length and were ferocious carnivorous animals with high intelligence.
- Discovered that strong jaws and a flexible body were the key to evolving into an apex predator in the ocean.
Overview
A research group consisting of Associate Professor Yasuhiro Iba, Academic Researcher Shin Ikegami, and Master's student Kanta Sugiura from the Faculty of Science at Hokkaido University, Professor Jörg Mutterlose from Ruhr University, Researcher Yusuke Takeda from the Japan Synchrotron Radiation Research Institute, Mehmet Oguz Derin and Dr. Takahiro Harada from Morgenrot Inc., Lecturer Aya Kubota from the Graduate School of Science at Osaka Metropolitan University, Professor Kazuki Tainaka from the Brain Research Institute at Niigata University, and Professor Emeritus Harufumi Nishida from Chuo University, developed an AI model capable of visualizing large-scale 3D data. By analyzing the jaw fossils of octopuses from approximately 100 to 72 million years ago (Late Cretaceous), they meticulously reconstructed their body size and ecology.
In conventional research, it was believed that over the past 400 million years in the ocean, vertebrates controlled ecosystem changes as apex predators, while invertebrates evolved as small prey. In contrast, this study revealed that the earliest octopuses living in the Late Cretaceous evolved into some of the largest carnivorous animals in the Cretaceous oceans, becoming apex predators despite being invertebrates. The estimated total length from the fossils reached 7 to 19 m, indicating that they could be the largest invertebrates in Earth's history. Furthermore, the AI model developed in this study enabled high-definition visualization of wear traces on the jaw surface created when chewing prey. This revealed that they were ferocious predators that crushed hard shells and bones to consume their prey. Additionally, it was discovered that the degree of this wear differed significantly between the left and right sides, revealing they had a "handedness" that suggests high intelligence. These discoveries indicate that strong jaws and a flexible body without a hard external shell or bones—an evolution common to both vertebrates and octopuses—are necessary conditions for evolving into an apex predator in the ocean.
This research outcome is scheduled to be published online in the journal Science on Friday, April 24, 2026 (Japan time).
[Background]
Apex predators, located at the top of the food chain, affect the entire ecosystem through the surrounding organisms they prey upon. It has been thought that apex predators in the ocean over the past 400 million years have been exclusively vertebrates with massive bodies and high physical capabilities, such as sharks, ichthyosaurs, and whales. On the other hand, invertebrates have been considered small prey that evolved shells for defense. In contrast, cephalopods, the group including octopuses, improved their motor functions through an exceptional evolution for invertebrates—losing their shells—and now thrive as moderately intelligent middle-tier predators. Among the octopuses and their ancestral groups that diversified during the Mesozoic Era (about 251 to 66 million years ago), large species exceeding 2 m in length were known, and they may have been formidable predators. However, in such species, no evidence showing their diet (*1) such as stomach contents had been found, leaving their role in past ecosystems unknown. This study, however, focused on the wear traces on the jaw surface formed when octopuses crush hard shells and bones, as evidence of them being predators.
[Research Methods]
This study updated the digital fossil mining method (*2) developed at the Iba Laboratory, Faculty of Science, Hokkaido University, by incorporating an AI capable of processing massive datasets, developed primarily by Morgenrot Inc. This enabled detailed observation of wear traces using high-definition digital 3D models (see [Related Press Releases]).
Using this method, 12 newly discovered octopus jaw fossils, including previously unknown juveniles, were found. Adding 15 jaw fossils reported from Hokkaido and Vancouver, Canada in previous studies, the classification, body size, and ecology of large Late Cretaceous octopuses (about 100 to 72 million years ago) were examined. For body size reconstruction, an equation was created to highly accurately reverse-calculate body size from jaw size based on measurements of 12 closely related extant species.
[Research Results]
As a result of the classification, five species, including those previously thought not to be octopuses, were consolidated into two species of the suborder Cirrina (*3). Additionally, the new specimens include the oldest record of octopuses, about 5 million years older than previously known. Body size estimations suggested that the older species reached a maximum total length of about 3 to 8 m, while the newer species reached about 7 to 19 m (Figure 1).
Points
- Successfully reconstructed detailed ecology by highly visualizing octopus jaw fossils using AI methods and analyzing surface traces.
- Revealed that octopuses from 100 million years ago reached up to 19 m in length and were ferocious carnivorous animals with high intelligence.
- Discovered that strong jaws and a flexible body were the key to evolving into an apex predator in the ocean.
Overview
A research group consisting of Associate Professor Yasuhiro Iba, Academic Researcher Shin Ikegami, and Master's student Kanta Sugiura from the Faculty of Science at Hokkaido University, Professor Jörg Mutterlose from Ruhr University, Researcher Yusuke Takeda from the Japan Synchrotron Radiation Research Institute, Mehmet Oguz Derin and Dr. Takahiro Harada from Morgenrot Inc., Lecturer Aya Kubota from the Graduate School of Science at Osaka Metropolitan University, Professor Kazuki Tainaka from the Brain Research Institute at Niigata University, and Professor Emeritus Harufumi Nishida from Chuo University, developed an AI model capable of visualizing large-scale 3D data. By analyzing the jaw fossils of octopuses from approximately 100 to 72 million years ago (Late Cretaceous), they meticulously reconstructed their body size and ecology.
In conventional research, it was believed that over the past 400 million years in the ocean, vertebrates controlled ecosystem changes as apex predators, while invertebrates evolved as small prey. In contrast, this study revealed that the earliest octopuses living in the Late Cretaceous evolved into some of the largest carnivorous animals in the Cretaceous oceans, becoming apex predators despite being invertebrates. The estimated total length from the fossils reached 7 to 19 m, indicating that they could be the largest invertebrates in Earth's history. Furthermore, the AI model developed in this study enabled high-definition visualization of wear traces on the jaw surface created when chewing prey. This revealed that they were ferocious predators that crushed hard shells and bones to consume their prey. Additionally, it was discovered that the degree of this wear differed significantly between the left and right sides, revealing they had a "handedness" that suggests high intelligence. These discoveries indicate that strong jaws and a flexible body without a hard external shell or bones—an evolution common to both vertebrates and octopuses—are necessary conditions for evolving into an apex predator in the ocean.
This research outcome is scheduled to be published online in the journal Science on Friday, April 24, 2026 (Japan time).
[Background]
Apex predators, located at the top of the food chain, affect the entire ecosystem through the surrounding organisms they prey upon. It has been thought that apex predators in the ocean over the past 400 million years have been exclusively vertebrates with massive bodies and high physical capabilities, such as sharks, ichthyosaurs, and whales. On the other hand, invertebrates have been considered small prey that evolved shells for defense. In contrast, cephalopods, the group including octopuses, improved their motor functions through an exceptional evolution for invertebrates—losing their shells—and now thrive as moderately intelligent middle-tier predators. Among the octopuses and their ancestral groups that diversified during the Mesozoic Era (about 251 to 66 million years ago), large species exceeding 2 m in length were known, and they may have been formidable predators. However, in such species, no evidence showing their diet (*1) such as stomach contents had been found, leaving their role in past ecosystems unknown. This study, however, focused on the wear traces on the jaw surface formed when octopuses crush hard shells and bones, as evidence of them being predators.
[Research Methods]
This study updated the digital fossil mining method (*2) developed at the Iba Laboratory, Faculty of Science, Hokkaido University, by incorporating an AI capable of processing massive datasets, developed primarily by Morgenrot Inc. This enabled detailed observation of wear traces using high-definition digital 3D models (see [Related Press Releases]).
Using this method, 12 newly discovered octopus jaw fossils, including previously unknown juveniles, were found. Adding 15 jaw fossils reported from Hokkaido and Vancouver, Canada in previous studies, the classification, body size, and ecology of large Late Cretaceous octopuses (about 100 to 72 million years ago) were examined. For body size reconstruction, an equation was created to highly accurately reverse-calculate body size from jaw size based on measurements of 12 closely related extant species.
[Research Results]
As a result of the classification, five species, including those previously thought not to be octopuses, were consolidated into two species of the suborder Cirrina (*3). Additionally, the new specimens include the oldest record of octopuses, about 5 million years older than previously known. Body size estimations suggested that the older species reached a maximum total length of about 3 to 8 m, while the newer species reached about 7 to 19 m (Figure 1).