Basic information: Blanket octopus , its Latin name: Tremoctopus violaceus Classification status: Mollusctopus Cephalopoda Octopus Orphanaceae Water Polygonaceae Water Polygonaceae
Origin of the name: Unlike other members of the octopus family, blanket octopus stretches a layer of muscle membrane between tentacles. When they spread their arms, the whole body looks like a blanket, hence their name, Blanket Octopus.
The function of "blanket": These blanket-like structures are obviously not for keeping warm! Instead, they use this net as the first line of defense against predators. When threatened, blanket octopuses stretch their arms to form a large net that scares off predators. When this trick of deception doesn't work, they don't spray ink like other octopuses, but "breaking arms escape" like geckos, i.e. discard their own "blanket" structure to confuse predators.
Reproductive features: Male blanket octopus is almost less than 5cm long, while some female blanket octopus can grow to an amazing 2 meters long. The male is so small that it can easily enter the female's pupils. A male blanket octopus weighs only a little heavier than a walnut, while a female blanket octopus weighs almost 40,000 times that of a male. This type of sex-size dimorphism in size and weight is called sex-size dimorphic (Sexual Size‐dimorphic).
Gender dimorphism: Gender dimorphism refers to the difference between different genders of the same species . The most basic homosexual shaped is a reproductive structure ( first sexual characteristics ), but because all sex organisms have differences in reproductive structures; generally speaking, homosexual shaped shaped mainly refers to other characteristics that have no direct relationship with reproduction ( second sexual characteristics 4 ), including body shape, color, body organs used as courtship or fighting, such as decorative feathers, antlers, horns and fangs.
Although blanket octopus is not the only species with similar characteristics, such a huge gap is rare in the animal kingdom! Moreover, due to the huge difference in gender dimorphism of this species, it creates the disadvantages of male gender. Therefore, male blanket octopus has been looking for females all their lives and serves only for breeding offspring. Each male octopus has a forelimb for breeding, and they will wander in the sea to find females. When males meet females, they cut the sperm-filled tentacles inside the females. The females store it in the outer cavity to use this tentacle to fertilize the egg. (Generally during this process, females basically do not notice mating behavior) After that, the female will leave the male, and the male will float in the water and wait for death.
Why does such a large gender dimorphism occur?
Marine scientists and biologists believe that male blanket octopus gave up growing during evolution and devoted most of its energy to finding female partners. There are also opinions that males are small in order to quickly mature sexually to spread genes; while females grow up to facilitate finding, and can also accept many male octopuses at the same time to increase the diversity of genes in the species .
Living habits: , because they are hidden between corners and gaps, or in open seas, blanket octopus is not easy to find.
Figure 1: Female blanket octopus
Figure 2: Male blanket octopus
Source: Aquatic animal health assessment (compilation)
Source: blanket octopus_Baidu Encyclopedia (baidu.com)
bing.com/images
https://zhuanlan.zhihu.com/p/83682241
