Stoloteuthis leucoptera

Geographic Range

Stoloteuthis leucoptera, also known as the butterfly bobtail squid is found in large oceanic waters like the Atlantic and Indian Oceans, and the Mediterranean Sea. The butterfly bobtail squid is also found in shoals off of the Straits of Florida, the Gulf of Maine, and Cape Cod, Massachusetts. (Groenenberg, et al., 2009; Steimle Jr and Terranova, 1988; Stillman, 1909; Stillman, 1912; Stillman, 1920; Villanueva and Sanchez, 1993)


Stoloteuthis leucoptera is most commonly found swimming freely in shoals around the shelf or slope around the upper bathyal area at 175 to 340 meters deep, although it has been seen coming up to mesopelagic zone during daytime hours. (Groenenberg, et al., 2009; Relini and Massi, 1991; Stillman, 1909; Stillman, 1912; Stillman, 1920; Villanueva and Sanchez, 1993)

  • Range depth
    175 to 340 m
    574.15 to 1115.49 ft

Physical Description

The butterfly bobtail squid is a small cephalopod with eight short appendages with 12 to 14 rows of suckers that are webbed together near the base. Two larger tentacles extend on both sides that are covered in suckers near the tip and form a club shape. The tentacles attach to the large mantle of the animal that has two semicircle fins extending from the anterior of the squid’s body for swimming. At either side of the head are the spherical eyes containing a small round pupil that allow the animal to reflect light, lower is where the light organs are located that contain Vibrio fischeri, a bacteria that lives inside of the sac that produces light for Stoloteuthis leucoptera. Sexual dimorphism is present in the species as males tend to be smaller, 17 mm in mantle length and contain modified tentacles for mating purposes. Females do not have specialized tentacles, but are larger in the mantle length at 18 mm. (Benli, et al., 2002; Fanelli, et al., 2012; Lindgren, 2010; Relini and Massi, 1991; Stillman, 1909; Stillman, 1912; Vecchionea and Galbraithb, 2001)

  • Sexual Dimorphism
  • female larger
  • Range length
    17 to 18 mm
    0.67 to 0.71 in


Not much is known about the butterfly bobtail squid's development other than most of the development happens in the egg and they hatch as tiny adults with their complicated systems already developed. Symbiosis with Vibrio fischeri begins immediately after hatching. (Benli, et al., 2002; Relini and Massi, 1991; Roeleveld, 1998; Steimle Jr and Terranova, 1988; Önsoy, et al., 1844)


Stoloteuthis leucoptera males fight each other to fertilize the females. To do so, the male inserts a specialized tentacle that carries a specialized ink sac containing the sperm into the funnel of the female. Females may hold onto these sacs from many mates before fertilizing its eggs. (Fanelli, et al., 2012; Groenenberg, et al., 2009; Stillman, 1909; Stillman, 1912; Stillman, 1920; Önsoy, et al., 1844)

A female can hold onto many different ink sacs from several matings with different males. They hold onto these ink sacs until fertilization happens in which the female will lay from 1 to 400 eggs, buried in the deep ocean sands. The parents die soon after. (Benli, et al., 2002; Cherel, et al., 2011; Fanelli, et al., 2012; Stillman, 1909; Stillman, 1912; Stillman, 1920; Önsoy, et al., 1844)

  • Breeding interval
    Butterfly bobtail squids breed only once in their lives.
  • Range number of offspring
    1 to 400

Females of Stoloteuthis leucoptera bury their eggs in the ocean sand, likely protecting them from predators. They likely also provide provisioning in the eggs for development. There is no further parental investment, as the adults die shortly after mating. (Groenenberg, et al., 2009; Stillman, 1909; Stillman, 1912; Stillman, 1920; Önsoy, et al., 1844)

  • Parental Investment
  • pre-hatching/birth
    • provisioning


No information can be found about the lifespan of Stoloteuthis leucoptera. The closest relatives to the butterfly bobtail squid, the cuttlefish (Order Sepiida), have a life span of one to two years. (Stillman, 1909; Stillman, 1920)


Stoloteuthis leucoptera normally travels in schools of other butterfly bobtail squid. It hides from predators through the coloration of its clear-bluish skin blending with the ocean water and light organs located below the eye that blend with light entering the ocean from above. (Benli, et al., 2002; Cherel, et al., 2011; Lindgren, 2010; Quetglas, et al., 2013; Roeleveld, 1998; Vecchionea and Galbraithb, 2001; Villanueva and Sanchez, 1993; Önsoy, et al., 1844)

Communication and Perception

Stoloteuthis leucoptera has two light producing organs under its eyes that contain Vibrio fischeri, a strain of bio-luminescent bacteria. The purpose of this organ is that it allows the butterfly bobtail squid to mask its presence among prey and predators by matching the light that comes from above. Its blue-ish coloration and transparency allow it to blend in with the environment below it. Stoloteuthis leucoptera also has large eyes that reflect light. (Relini and Massi, 1991; Roeleveld, 1998; Stillman, 1912; Villanueva and Sanchez, 1993)

  • Communication Channels
  • visual

Food Habits

Stoloteuthis leucoptera is a carnivore that typically hunts at night, consuming many types of small bony fish, crustaceans, and even smaller squids. (Benli, et al., 2002; Cherel, et al., 2011; Roeleveld, 1998; Stillman, 1920; Önsoy, et al., 1844)

  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans


Stoloteuthis leucoptera is consumed by mainly marine mammals and large bony fish that can dive deep enough to find them. In defense the butterfly bobtail squid uses its coloration to hide from predators with its clear-bluish body blending with the deep waters when looking down and light organs below its eye to match the light pouring in from above the ocean when looked from below. Stoloteuthis leucoptera is also locally fished by humans for food. (Benli, et al., 2002; Quetglas, et al., 2013; Relini and Massi, 1991; Roeleveld, 1998; Steimle Jr and Terranova, 1988; Vecchionea and Galbraithb, 2001; Villanueva and Sanchez, 1993)

  • Anti-predator Adaptations
  • cryptic
  • Known Predators
    • marine mammals
    • bony fish, Osteichthyes
    • humans Homo sapiens

Ecosystem Roles

Stoloteuthis leucoptera primary controls the populations of many small crustaceans and squids by consuming them. In return is also a part of the food chain for many oceanic mammals and large bony fish. Stoloteuthis leucoptera also has a mutualistic relationship with Vibrio fischeri, a strain of bio-luminescent bacteria. The bacteria live in two pockets on the squid, producing light and helping to camouflage the squid in the water. (Relini and Massi, 1991; Stillman, 1912)

Mutualist Species
  • bacteria, Vibrio fischeri

Economic Importance for Humans: Positive

Stoloteuthis leucoptera is fished and used as food and nourishment for local villages near the waters they inhabit. Research is also being done on its ability to produce light along with many other benthic organisms that live in the deep oceans. (Benli, et al., 2002; Cuccu, et al., 2010; Groenenberg, et al., 2009; Relini and Massi, 1991; Roeleveld, 1998)

  • Positive Impacts
  • food
  • research and education

Economic Importance for Humans: Negative

There are no known adverse effects of Stoloteuthis leucoptera on humans.

Conservation Status

Conservation status of Stoloteuthis leucoptera as listed in the IUCN red list is data deficient. Very little is known about this species, making it difficult to assess its conservation status. ("IUCN Red List of Threatened Species", 2013)


Benjamin Ousley (author), Radford University, Karen Powers (editor), Radford University, Angela Miner (editor), Animal Diversity Web Staff.


Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

World Map


Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


an animal that mainly eats meat


the nearshore aquatic habitats near a coast, or shoreline.


used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.


having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature


union of egg and spermatozoan


A substance that provides both nutrients and energy to a living thing.


having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

internal fertilization

fertilization takes place within the female's body


eats mollusks, members of Phylum Mollusca


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


active during the night


reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).


generates and uses light to communicate


an animal that mainly eats fish

polarized light

light waves that are oriented in particular direction. For example, light reflected off of water has waves vibrating horizontally. Some animals, such as bees, can detect which way light is polarized and use that information. People cannot, unless they use special equipment.


the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.


offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.


reproduction that includes combining the genetic contribution of two individuals, a male and a female


that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


uses sight to communicate


2013. "IUCN Red List of Threatened Species" (On-line). Accessed April 03, 2014 at

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