Recently, if a friend diving in the shallow water of Blairgowrie in Port Phillip Bay, Victoria, be careful to be surprised by the "live carpet" under your feet!
Yes, the annual spider-crab migration is coming again!
They are vast, they are in droves, on their way of migration, everything is floating clouds!
Whoever gets in my way, I'll climb over! If I can't climb through it, I'll get around it!
The last video let everyone feel this tenacious will.
http://mp.weixin.qq.com/s?src=3×tamp=1488412463&ver=1&signature=YZLXW4QsecwhHgJJV4VE1*ChCcIYY4aQ1dD5tDYVS3CBoLnJXpWpeZ7iM2zKIXqMelIyvUJ0e5u2HCFZib8lBg6ARoneOpadU1mMOgA39rIOJonnlxbK1*b*NRstvrOhc0viEjEdp5Q28iDmA*QFK3iSeb7Hn1DVPmuMnBGfSQI=
This animal is a special spider crab in Victoria, is a kind of sea crab, because it looks like a spider, so it is named spider crab.
They live in the sea all the year round, and we usually can't see it.
But every autumn, the crabs shed their shells. Exuviate the old shell and grow a new, harder shell.
That is, once a year, "exchange old for new", so that they can more valiantly fight in the sea floor, bravely predator!
Spider crab has the name of "undersea killer"!
They are usually waving big pliers, all kinds of hand squid in the words!
Deciduous spider crabs also use crab pliers to clamp their eyes.
It's not a habit of self-harm, it's about releasing hormones that molt.
The annual molting period is in fact the weakest period of the year for spider crabs.
At this time, there are a lot of spider crabs "fans" will take advantage of the empty, swallow them into the abdomen.
For example, stingray, sharks, dolphins, seabirds, can like to eat molted shell spider crab.
It turns out that not only do we humans like to shell and eat crabs.
PS: checked it out. Spiders and crabs are non-toxic and edible.
So, every time the spider crabs shed their shells, they gather away from the powerful hunters in the deep sea and migrate to safer shoals.
When they migrate, they support each other and stack together! Up to a dozen meters! Like a moving submarine pyramid!
The question is, scientists still can't explain why spider crabs shed their shells together.
Isn't this huge team more likely to attract predators?
Xiao Wei guessed, they must be hoping to kill the enemy by sacrificing their outsider companions! So that other members can escape safely.
In the past year, spider crab migration day should be in May-June, I do not know why the end of February this year all moved to the shoals. Two months ahead of time! This is the first time in history that spider crabs begin to migrate so early.
Victoria's chief animal conservation scientist, Mark Norman, could not explain either, but said they did not begin to shed their shells early, though they had moved early.
Taken on Feb. 27, spider crabs have thick old shells.
So maybe the migration of spider crabs has nothing to do with molting? Is it for breeding?
There are still a lot of mysteries unsolved about this annual migration event.
We have to wait for the scientists to study and explore and solve these mysteries for us.
Finally, small friendship remind, even if spider crabs look delicious, we should not at will catch oh.
Let them migrate and molt quietly.