That these crabs have a strong homing sense, or an affection for certain localities, was demonstrated some years ago. Two crab fishermen were following their occupation from the same boat, and each as he caught a crab cut upon its swimming claw a private mark so that they could be claimed by the rightful owners at the end of the day. The boat was overtaken by a storm and the crabs were tipped overboard five miles from where they were caught and lost. The following week the two men again began to fish in the original spot, and to their amazement began to catch the marked crabs, which had returned five miles alongshore to the locality of their choice.
The so-called green crab (Fig. 148) is an attractive and active creature, one that can easily be observed. Its quaint stalked eyes, which turn this way and that, and which can be stowed away in little depressions, and its singular method of walking, are very interesting features. When a crab walks on land it is usually endwise, and when it wishes to change its course it is not obliged to turn about but moves its legs in the opposite direction. It can also move directly ahead. These movements are all performed by six legs, which are pointed, the trail of this crab on the sand resembling pin marks on the hard beach. The two front claws are for tearing food and for general defense, while the last pair, widened out at the end in some, are paddles by which the crab swims when it ventures off the bottom.
Fig. 148.—The green crab.
At times the crabs appear to migrate. I have seen the bottom of a bay on the Virginian coast so covered that it was impossible to wade without stepping upon a crab. In the island of Jamaica certain land crabs march to the sea to deposit their eggs, at which time they appear more or less indifferent to danger, and move on, despite the attacks of birds and various animals, including man.
The crabs known as fiddlers (Fig. 149) are common up and down the Atlantic coast, especially in the warmer portions. A most interesting colony lived north of Fernandina, Florida. Some years ago a plank walk led across their domain, and one could stand and watch their ludicrous maneuvers. The fiddler is not over an inch in length. It is of a dark ivory hue, and its eyes are perched on long stalks, so that it can bury itself in the mud and thrust its eyes upward, and thus in perfect safety observe everything that is going on. The right claw of this crab is half as long again as its entire body—a colossal weapon framed for an animal five or ten times its size. Indeed, it is so large as to be almost useless, for a large amount of strength is required to operate so gigantic an implement. To emphasize the undue size of this claw, the left one is a dwarf, being too small to act as a defensive weapon. How so small a crab can use so strange a pair of weapons was a puzzle, until by watching them, I discovered that the crab uses its large claw as a bogy, brandishing it fiercely, which gives it a very ferocious appearance. The movement of the claw back and forth is called fiddling, hence the name of the crab, which appears to be constantly fiddling. Where hundreds are seen, all fiddling and menacing one another at the same time, the sight is laughable.
Fig. 149.—Fiddler crab.
Fig. 150.—Spider crab.