ANIMAL PARTNERSHIPS.

Star (Christchurch), Issue 17027, 28 April 1923, Page 9

ANIMAL PARTNERSHIPS.

STRANGE HAPPENINGS IN NATURE. Animals (writes Professor J. Arthur Thomson in ‘‘John o’ London’s Weekly ’) are always looking out lor some new niche of opportunity; they are always sending out what might be called tentative tendrils. Thus we find a spider living inside a pitcher plant, an earthworm up a- tree, brine shrimps in the Great Salt Lake of Utah, barnacles on the tail of a. sea sngke, a score of animals in a. coal pit, a dozen in a hocspring, water snails browsing on stones just on the verge of the Niagara Cataract, and thousands of animals in the eternal night of the Deep Sea. Or, again, we find all sorts of strange experiments in the quest for food—a woodpecker tapping th e sweet sap of the sugar maple, the Kea parrat attacking living sheep, a dog-whelk browsing on acorn shells, ants nicking green flies, th e medicinal leech sucking blood, the leaf-cutter ants growing a palatable mould on a green paste made of chewed leaves, the crocodile-bird entering the reptile’s mouth, and picking its teeth, and so on through a very long list. Hermit-crabs have, as everyone knows, a soft and vulnerable tail. They have learned to protect this by ensconcing themselves in a borrowed shell, usually that ot some sea-snail—-such as perriwinkle or wlielk. Rut there ar e some of them which go much further, for they fix sea-anemones on the back of the shell they have borrowed. The result is a small mutual benefit society. The hermit-crab is benefited, for his partners mask his real nature, and then they carry batteries of stinging cells. The sea-anemones—-there may be three or four, or only one —must also have their reward, for, unlike their fellows that are fixed to the rocks, they are always being carried about, and then they get crumbs from their partner’s table. When the her-mit-crab has grown so big that he must change his house, he lias been seen shifting the sea-anemones to the new shell. This suggests not only that the partnership is very useful, but that the hermit-crab is aware of the fact. In some cases a sea-anemone is fixed near the end of the great claws of the crab, and is evidently used as a weapon.