The ommastrephids are small to large squids, with mantle lengths ranging from that of the glass squid (Hyaloteuthis pelagica) at 9 cm (3.5 in), to the Humboldt squid (Dosidicus gigas) at 1.5 m (4.9 ft).
The mantle narrows towards the back and possesses large terminal fins.
The family is characterized by an inverted T-shaped funnel locking cartilage.
They have an easily recognizable, slender, feather-shaped gladius with a hollow cone structure (the primary conus).
Light organs (photophores) are present along the head and mantle of members of the subfamily Ommastrephinae.

Ommastrephid arms have a double series of suckers.
The enlarged tips (the clubs) of the tentacles have four rows of suckers, except in the genus Illex, which has eight.
Hooks are absent.
One of the ventral arms develops into a secondary sexual organ (the hectocotylus) in males.

All ommastrephids are active predators.
Their arms and tentacles bear sharp teeth and are used to grasp and bring prey to their beaked mouths.
They are very strong swimmers, and some species are known to glide out of water to escape predators.

Ommastrephid paralarvae are distinctive for having fused tentacles, looking like a single "proboscis".
It gradually splits into two as the paralarvae grow becoming completely separated once they reach mantle lengths of 5 to 10 mm (0.20 to 0.39 in).
The ommastrephids are small to large squids, with mantle lengths ranging from that of the glass squid (Hyaloteuthis pelagica) at 9 cm (3.5 in), to the Humboldt squid (Dosidicus gigas) at 1.5 m (4.9 ft). The mantle narrows towards the back and possesses large terminal fins. The family is characterized by an inverted T-shaped funnel locking cartilage. They have an easily recognizable, slender, feather-shaped gladius with a hollow cone structure (the primary conus). Light organs (photophores) are present along the head and mantle of members of the subfamily Ommastrephinae.
Ommastrephid arms have a double series of suckers. The enlarged tips (the clubs) of the tentacles have four rows of suckers, except in the genus Illex, which has eight. Hooks are absent. One of the ventral arms develops into a secondary sexual organ (the hectocotylus) in males.
All ommastrephids are active predators. Their arms and tentacles bear sharp teeth and are used to grasp and bring prey to their beaked mouths. They are very strong swimmers, and some species are known to glide out of water to escape predators.
Ommastrephid paralarvae are distinctive for having fused tentacles, looking like a single "proboscis". It gradually splits into two as the paralarvae grow becoming completely separated once they reach mantle lengths of 5 to 10 mm (0.20 to 0.39 in).
Ommastrephidae