Strawberry squid is one of the most remarkable squid species known today. It stands out at first glance because its eyes are notably unequal in size and appearance. One eye is smaller and blue, while the other is larger and yellow. The larger eye likely helps it spot objects in the faint light near the surface, whereas the smaller eye seems tuned to survey the darker seafloor below.
Another striking feature is the color of its skin. The squid earns its common name from its deep red pigmentation and the presence of light-producing organs called photophores woven through its body, giving it a vivid, strawberry-like look.
This species inhabits the mesopelagic zone of the ocean and can be found along the Pacific’s California Current and Humboldt Current. Details about its feeding and mating behaviors remain limited, but it is known to be prey for larger predators such as certain sharks and sperm whales, which helps illustrate its place in the wider food web.
The two eyes of the squid are often noted for their dramatic contrast, a feature that has sparked curiosity among researchers and enthusiasts alike. In recent observations, it has been described as a living example of adaptation to two very different environments in the open ocean.
Although strawberry squid (Histioteuthis heteropsis) has been recognized by science for decades, a recent expedition to Ascension Island and Saint Helena brought back specimens with striking ultraviolet illumination. When exposed to ultraviolet light, the squid’s small body glowed with ruby-red spots, creating a stunning bioluminescent display.
Researchers quote that once a squid measures about 15 centimeters in length, the red glow becomes especially intense; the closer the observer gets, the stronger the color appears. This observation has contributed to a broader appreciation of how deep-sea creatures can respond to different wavelengths of light in their environment.
There is a notable lack of prior attempts to illuminate deep-sea animals with ultraviolet light, making these findings particularly exciting. Some related species, such as jewel squid and viperfish, display bright red photophores, while others like certain anglerfish do not exhibit the same trait, underscoring the diversity of bioluminescence strategies in the ocean.
Emits light from the body
The photophores of Histioteuthis heteropsis serve two primary purposes: counter-illumination and environmental adaptation. The squid emits blue light so that, when viewed from above, its silhouette blends with the downwelling sunlight, effectively masking its presence from predators. This continuous bioluminescence helps the animal stay inconspicuous in the open water. When escape becomes necessary, the squid can produce abrupt bursts of bright light, a rapid flashing that can confuse pursuers and create a chance to flee.
In the wild, H. heteropsis plays a role in the diets of several marine predators, including tuna, dolphins, blue sharks, sperm whales, elephant seals, and albatrosses. While detailed stomach-content analyses are scarce, available assessments suggest the squid feeds on smaller fish, crustaceans, and other cephalopods, contributing to the nutrient flux within its ecosystem.
In historical records, Berry first described the strawberry squid in 1913, recognizing it as part of the Histioteuthis family due to the abundance of photophores. Morphological features indicate close relationships within the genus, particularly among species such as Histioteuthis meleagro teuthis and Histioteuthis bonnellii, which share luminous traits and structural similarities.
Conservation assessments conducted by the International Union for Conservation of Nature (IUCN) classify the strawberry squid as Least Concern. There are currently no known major threats to the species, and population data are sparse. The IUCN emphasizes the need for further research to better understand its abundance, distribution, and ecological role within pelagic ecosystems.
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To learn more about the environment and research efforts related to this species, researchers and institutions continuously gather data on deep-sea cephalopods, including feeding habits, habitat preferences, and bioluminescent strategies. These studies contribute to broader knowledge of oceanic life and illuminate how deep-sea creatures adapt to the challenges of dim light and vast depths.
Note: This article draws on historical taxonomic work and contemporary field observations to present a cohesive profile of the strawberry squid, with careful attribution to scientists and museums that have contributed to understanding this unique animal.