iles of
trackless waste to their birthplace, where they breed. When they reach
the Antarctic shore they walk with determination to a suitable site,
often at the top of a steep cliff. Some species waddle 130 steps per
minute, 6 inches per step, two-thirds of a mile per hour.]

The Mind of a Minnow

To find solid ground on which to base an appreciation of the behaviour
of fishes, it is necessary to experiment, and we may refer to Miss
Gertrude White's interesting work on American minnows and sticklebacks.
After the fishes had become quite at home in their artificial
surroundings, their lessons began. Cloth packets, one of which contained
meat and the other cotton, were suspended at opposite ends of the
aquarium. The mud-minnows did not show that they perceived either
packet, though they swam close by them; the sticklebacks were intrigued
at once. Those that went towards the packet containing meat darted
furiously upon it and pulled at it with great excitement. Those that
went towards the cotton packet turned sharply away when they were within
about two inches off. They then perceived what those at the other end
were after and joined them--a common habit amongst fishes. Although the
minnows were not interested in the tiny "bags of mystery," they were
even more alert than the sticklebacks in perceiving moving objects in or
on the water, and there is no doubt that both these shallow-water
species discover their food largely by sense of sight.

The next set of lessons had to do with colour-associations. The fishes
were fed on minced snail, chopped earthworm, fragments of liver, and the
like, and the food was given to them from the end of forceps held above
the surface of the water, so that the fishes could not be influenced by
smell. They had to leap out of the water to take the food from the
forceps. Discs of coloured cardboard were slipped over the end of the
forceps, so that what the fishes saw was a morsel of food in the centre
of a coloured disc. After a week or so of preliminary training, they
were so well accustomed to the coloured discs that the presentation of
one served as a signal for the fishes to dart to the surface and spring
out of the water. When baits of paper were substituted for the food, the
fishes continued to jump at the discs. When, however, a blue disc was
persistently used for the paper bait and a red disc for the real food,
or _vice versa_, some of the minnows learned to discriminate infallibly