Behaviour

Tomopteris planctonic polychaete worm. (uwe kils / Wikimedia / CC BY-SA 3.0)

Light in the Darkness: The Mystery of Bioluminescence

What is bioluminescence?

Bioluminescence is the ability of living organisms to produce light through a chemical reaction. In the ocean, it is everywhere—from microscopic plankton near the surface to bizarre fish that haunt the deepest trenches. It is estimated that over 75% of animals in the deep ocean are bioluminescent in some form. In this dark world, light is language, lure and lifeline.

A rig shark
A rig shark (mustelus lenticulatus) (Arnim Littek, CC BY 4.0)

Clicks from the Deep: Scientists Record First-Ever Shark Sounds

In a world-first, marine researchers in New Zealand have recorded rig sharks (Mustelus lenticulatus) producing clicking noises underwater. Their study documenting this remarkable behaviour by the small, bottom-dwelling shark, found around New Zealand’s coast, is making waves in the scientific community.

What's All the Clicking About?

Unlike many fish that use swim bladders to make sounds, sharks don't have that option. So how are these clicks happening?

Gray reef shark (Carcharhinus amblyrhynchos)

Some Sharks May Bite in Self-Defense Rather Than Aggression

Shark attacks are often sensationalized, reinforcing the perception of sharks as mindless predators. However, new research conducted in French Polynesia indicates that a small number of shark bites may be defensive reactions triggered by human behavior perceived as threatening. These findings challenge long-standing assumptions about shark motivations and call for a shift in how such incidents are interpreted.

DolphinGemma is an open-source AI model developed to analyse dolphin vocalisations.

DolphinGemma: Google’s AI Dives Into Dolphin Communication

Developed in partnership with the SETI Institute and marine biologists, the project aims to build the first systematic tool for analysing dolphin communication using a Large Language Model (LLM) architecture, similar to that used in human text-based AI systems.

Octopus Is Spotted Riding a Shark

The moment, captured on video by researchers from the Auckland University of Technology, has quickly attracted international attention.

While octopuses are known for their intelligence and problem-solving abilities, such behaviour is highly unusual. Researchers suggest the octopus may have been using the shark as cover, attempting to avoid predators or navigate more efficiently through the water. It is also possible the octopus was defending itself after an attempted predation by the shark.

Antarctic krill.
Antarctic krill.

Penguin Guano Sends Krill Into High Alert

A recent study has revealed that penguin guano in the water can significantly alter the swimming and feeding behaviour of Antarctic krill, a keystone species in the Southern Ocean. 

The research, published in Frontiers in Marine Science, shows how the presence of chemical cues in penguin guano can trigger an escape response in krill, potentially affecting the Antarctic food chain.

Orcas
Orcas (unknown author / CC BY-SA 4.0 via wikimedia commons)

Killer Whales' Specialized Attack on Whale Sharks

The study, which was led by Francesca Pancaldi, used photographic and video evidence to show how a pod of killer whales (Orcinus orca) employed a collaborative approach to target the whale sharks' pelvic area, including the claspers and pelvic fins. This strategy caused significant blood loss and allowed the killer whales access to the sharks’ lipid-rich livers, which is a highly nutritious part of the prey.