[2] This crustacean has a hard rounded-triangular shell, or carapace, that is covered in hair-like projections that vary in size.

[5] The seaweed crab is broadly dispersed across New Zealand shorelines on both the North and South Islands.

[5] The seaweed crab can be found along the coast amid rocks in tide pools and the intertidal zone.

[5] The female seaweed crab lays fertilized eggs from which larvae develop and break free.

The eggs are bright orange when freshly laid and turn brown as they approach time to hatch, and are approximately 0.75mm across.

[4] Crabs are typically scavengers, meaning that they eat whatever they can find, and as omnivores this includes both plants and other animals.

Other common foods included isopods, amphipods, and decapods (e.g. small fish, crayfish, other crabs).

Seaweed crabs use their claws to tear apart their food, and predation techniques vary based on the mobility of the prey.

[6] The types of algae for masking may also be chosen based on “calorific value or content of vitamins, nitrogen, or specific nutrients such as sugars and amino acids”.

[6] N. ursus uses its chelipeds to execute a wide variety of feeding techniques that it uses on those different types of prey.

Small arthropods, juvenile crayfish and polychaetes were obtained by probing around with opened chalae and quickly closing them when they contacted the prey.

Studies have shown a significant decrease in the predation experienced by decorated seaweed crabs compared to ones that had been cleaned.

They have teeth to break down the material they consume and setae, hair-like structures, to aid in the process.

Pappose setae might perform a range of functions such as chemoreceptors, mechanoreceptors, gap sealants, or scrapers.

[11] As mentioned in the diet section, decorating behavior of seaweed crabs is thought to be a method of food storage in addition to camouflage.