Reader question – Rubens Camargo, Jataizinho, PR
DARK CURTAIN
The ink serves to confuse predators. The octopus measures the amount ejected in case it gets into more than one mess a day. A small animal, measuring around 20 cm, stores around 1 ml of ink while a large octopus, measuring over 2 m, produces around 20 ml, enough to create a dark cloud in the water.
JET ESCAPE
To escape danger, the siphon, an internal funnel-shaped muscle, comes into action. When it senses threat, the animal chooses a route to escape. Then, the siphon sucks sea water into the octopus and expels it with force, giving it an impetus for escape. Depending on the danger, it releases ink with the squirt to confuse the predator.
RAW COLOR
The production rolls in the ink gland and the storage in the bag. The raw material of ink is melanin, the same pigment that gives color to our skin. The difference is that it is very concentrated (giving it a black or dark brown color). The dark liquid is reserved for emergencies.
MILD POISON
In addition to melanin, which darkens water, the ink also contains tyrosinase, lysine and aspartic acid, enzymes that irritate and stun predators. After emptying the bag, it starts to synthesize the substance again and fills it up in a few hours – at most a day later.
Some species of octopus confuse predators by changing color. In addition to camouflage, this also warns others of the species of danger of attack.
Consultancy Teodoro Vaske, oceanographer specializing in cephalopods at the São Paulo State University (Unesp)