Octopuses, jellies and other invertebrates

Explore shells, arms, life cycles, molting and photosynthetic partnerships in octopuses, nautiluses, crustaceans, jellies, clams and coral animals.

1. Animal profiles

   Giant Pacific octopuses: camouflage, suckers and a short reproductive life ↗

   The giant Pacific octopus combines color-changing skin, texture changes and sensory suckers to navigate and blend into its surroundings. Females guard egg strings while fasting; hatchlings enter a planktonic stage, and the species’ typical lifespan estimate is three to five years.

2. Animal profiles

   Nautiluses: chambered shells, buoyancy and slow reproduction ↗

   A nautilus’s shell compartments help regulate buoyancy, while a separate jet propels it. Its anatomy, lensless eyes and slow reproductive pace distinguish it from familiar cephalopods and help explain its vulnerability to collection.

3. Animal profiles

   Blue crabs: molting, migration and life in an estuary ↗

   Blue crabs grow by shedding a rigid exoskeleton, and their life cycle shifts among estuarine habitats. Paddling legs, sex-specific abdominal shapes, larval stages and a North Carolina tagging study help explain how to read their biology and movement evidence.

4. Animal profiles

   American lobsters: molting, claws and lifespan myths ↗

   American lobsters grow by molting, use their differently shaped claws for different tasks, and carry eggs beneath the tail. Their age is difficult to establish, so size and possible longevity estimates should not be mistaken for a known birthday or lifespan.

5. Animal profiles

   Moon jellies: a life cycle beyond the familiar bell ↗

   A moon jelly’s familiar bell is only its swimming adult stage. Across the genus Aurelia, sexual reproduction, settling larvae, attached polyps, budding and strobilation connect that visible medusa to less visible stages that can produce many young jellies.

6. Animal profiles

   Giant clams: photosynthetic partners and life on a reef ↗

   Giant clams combine suspension feeding with nutritional support from photosynthetic dinoflagellates living in mantle tubules. Their size, shell form and reef habitat vary by species; the largest, Tridacna gigas, faces documented harvest pressure across much of its range.

7. Animal profiles

   Coral animals: polyps, skeletons and reef-building partnerships ↗

   Corals are animals built from solitary or colonial polyps, and some stony corals add calcium carbonate skeleton that forms reef framework. Shallow reef corals may host photosynthetic algae, while deep-water corals feed without sunlight-dependent partners.

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