“FLAMBOYANT” CUTTLEFISH

This new post augments one I did on August, 2019. This update focuses on two examples of exotic/very colorful examples of so-called "flamboyant" cuttlefish.

First, however, a few summary comments about cuttlefish. They are marine mollusks (sepiids) related to squids and octopus. Cuttlefish can change color and texture in an instant in order to provide camouflage or to communicate. They live in tropical, shallow-marine waters (mainly the western Pacific Ocean) where coral reefs and sea grasses are present. They are absent from the Americas.

Cuttlefish are mostly small (rarely exceed 0.5 m in length) and have flattish bodies. Their bodies are flat, and they have large eyes with W-shaped pupils. They have 10 appendages: eight arms (with suckers) near the head and also two much longer tentacles, which extend along the sides of their body. Their eyes are large and have W-shaped pupils. They also have a sharp, parrot-like beak. They use their fins for swimming and for jet propulsion (i.e., they expel water from their interior mantle area). They can also release dark colored ink to confuse predators.

They have internal shell, called the cuttlebone-[note: pet stores sell these cuttlebones for  caged birds to gnaw on, thereby keeping their bird beaks sharp.] The cuttlebone, which consists of porous aragonite [calcium carbonate], is a unique internal gas-filled chamber that provides buoyancy for the cuttlefish.

Cuttlefish have a sharp beak (they can bite you!); thus they eat small mollusks, crabs, shrimp, fish, octopus, worms and other cuttlefish. In turn, cuttlefish are eaten by dolphins, sharks, other large fish, seals, and seabirds. Cuttlefish have a lifespan of about two years. They are born as mini-adults with no larval stage. 

Cuttlefish are eaten by dolphins, sharks, seals, and seabirds.

Almost all cuttlefish are venomous! Their venom is mostly mild, except for the “flamboyant cuttlefish,” [see two examples shown in Figures 2 and 3, below]. The venom of these flamboyant cuttlefish is as seriously lethal as that of the blue-ringed octopus!

There are about 120 known species of cuttlefish. They are up to 30 inches (75 cm) in length. They have one of the brain-to-body size ratio of all invertebrates. Thus, they are highly intelligent. Another interesting fact is that they can change their body color in an instant. The largest cuttlefish can weigh up to 23 pounds!

  Classification (note: they are neither a squid nor an octopus)

Kingdom Animalia

Phylum Mollusca

Class Cephalopoda

Order Sepiidae

Family Sepiidae

Genus Sepia (there are about 12 extant extant genera)

Type Species Sepia officinalis

The geologic time range of cuttlefish is Miocene to Recent. 

Figure 1. Sepia swimming:

Figure 2. A camouflaged, venomous “flamboyant” cuttlefish:

Figure 3. Another venomous example of a “flamboyant” cuttlefish:

All the images are from picryl.com [=public domain].

REFERENCES:

G. Ross (editor). 1998. Family Sepiidae, pp. 505-509. In Mollusca The Southern Synthesis. Part A. Fauna of Australia Volume 5. Chapter 13, pp. 504-508. 

 WIKIPEDIA, 2026