Easy to overlook at first glance, the mantis shrimp flickers in and out of view, its body painted in iridescent greens, blues and reds. But behind those colours lies something far stranger. It does not see the world as we do. It sees a world we cannot even imagine.

Independent eyes 

Each of the mantis shrimp’s eyes sits on a stalk, moving independently. One eye can look forward, while the other scans behind. Each eye alone can judge depth, something humans need two eyes to achieve. 

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.

Mantis shrimp are equipped with hammer-like dactyl clubs capable of storing and releasing immense energy in an instant. The clubs propel forward with explosive force, shattering mollusk shells and even cracking aquarium glass. A new study led by Northwestern University has discovered that it doesn’t just rely on toughness—it also uses advanced shockwave filtering mechanisms to protect itself.

For most people, the word “crustacean” brings to mind images of crabs, shrimp, lobsters, even krill. Crayfish is usually not in this list unless one is a chef or lives in Louisiana, where the state crustacean is the crayfish.

Crayfish are a keystone species, engineering habitats and serving as essential links in the food chain. However, habitat destruction, pollution and invasive species have left many species struggling to survive. In contrast, some species exported to Europe have flourished to the point that they compete with the native species and spread diseases.

A new species of hermit crab, distinguished by its striking crimson claws, has been described by scientists at Queensland Museum. 

The discovery was described by Queensland Museum Honorary Peter Davie and Queensland Museum Collection Manager Dr. Marissa McNamara. It places the hermit crab in relatively deep waters, between 120 and 260 meters, off southeastern Queensland. 

Behavioural innovation is thought to play an important role in enabling animals to cope with environmental change. Research on animal innovation has focused on terrestrial and freshwater vertebrates, but few animals face environmental variation as extreme as those living in littoral zones, where physical and social conditions change dramatically from moment to moment.

The aim of this thesis was to study the chemical communication involved in aggressive and reproductive behaviours in the European lobster (Homarus gammarus). Both male and female H. gammarus established and maintained dominance, but the sexes used different strategies for dominance maintenance.

Male losers recognised individual fight opponents and avoided them but fought actively against unfamiliar dominants. In contrast, female losers avoided both familiar and unfamiliar dominants, indicating that they react to the dominance status of the opponent.

In ancient China crabs were smashed open and thrust into wounds in battles because chitosan is antimicrobial, meaning it heals and kills bacteria.

Chitosan's properties allow it to rapidly clot blood and promote hemostasis (stops bleeding). Chitosan bonds with platelets and red blood cells to form a gel-like clot which seals a bleeding vessel.

Last September, ecologist David Johnson and his colleagues were at a Virginia salt marsh at low tide. There, they observed some unexpected behaviour by an aquatic predator.

They witnessed blue crabs waiting in shallow, water-filled pits, stalking and ambushing fiddler crabs above land, at low tide.

After capturing their prey, they would carry it back to the pit to consume it, then discard the large claws of the fiddler crab at the edge of the pit.