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Hermit Spadefoot — Part 3
The chorus is somewhat unusual in quality, and when it is heard at night it takes on an extra note of weirdness from the surroundings. An idea of its effectiveness can be gained by reading the accounts of it given by various observers. Now it is described as "a loud bellowing," again it is said to consist of "weird plaintive cries," or of "shrill ear-piercing groans." One writer calls it "a deafening, agonizing roar, hoarse and woeful."
After the eggs are laid, the Spadefoot Toads disappear entirely, leaving no trace of their hiding-places. In fact, it is not known whether they burrow in the neighbourhood of low land where temporary pools are likely to form, or whether they go a considerable distance into higher land before they burrow. At any rate, these facts are well authenticated: They disappear with never a stray one left behind, and they may not appear again in the same locality for many years.
They leave the pond filled with eggs--strings of eggs fastened to grass blades or stretched from weed to weed. In most of the cases observed, the ponds dried up before there was time for the development of the eggs, and in all cases the development seemed to be hastened because of the drying of the pond. The eggs hatch in from seven to fifteen days, according to the temperature.
The tadpoles appear velvety black in water, but when examined closely are rich brown in colour. They are short and stout-bodied, with narrow, spotted tails. In about two weeks after hatching, the delicate thread-like arms appear and the absorption of the tail begins. They leave the water while the tails are still quite long. Like toads, they will drown if they have no opportunity to get out on land. The tadpoles may show the yellow dorsal lines characteristic of the adults even before the front legs appear.
The first instinct of the little Spadefoots is to burrow. The feet are supplied with the apparatus for digging, although it is not as hard and horny as it becomes later, and so necessitates making the burrow in soft earth. The diminutive creatures have been observed to feed greedily on flies and young spiders.
One observer records an exodus of thousands of young Spadefoot toads from their native pond. For hours they "trudged" in leisurely fashion up a steep hill, apparently not stopping for food on their way. (The life history of the Hermit Spadefoot is taken from the accounts of various observers cited in Bibliography, pp. 241 to 250.) When picked up in the hand, they made a faint squeaking noise.
The adult Spadefoot is an unintelligent and somewhat uncanny-looking creature--its appearance quite matching its mysterious habits and underground life.(Fig.15.) The wide, rounded head bears two extremely prominent eyes set far apart. The vertical pupil has a narrow downward-projecting slit at the lower end. The iris has a black triangular indentation at its anterior margin. One-fourth inch behind the eye and about equalling it in size, is a round parotoid gland.
The skin is smooth, compared with that of the common toad, but on close examination is seen to be finely warty. While attached firmly in the region of the head, it is loosely attached on much of the body, and wrinkles at every turn. (See Figs. 16 and 18.) When the Spadefoot is in resting position, the loose skin of the upper arm extends in a fold down over the lower arm and hand.
The fingers are thickened at their tips; there is a black, horny thickening of the upper surfaces of the two inner fingers. (See Fig. 15.) The foot is depressed, and the skin covering it is thick and somewhat horny in character, converting the foot into a living spade. At the base of the shortest toe is a long, black, horny spur to aid in digging. The same black horny substance is seen at the tip of this inner toe.
Except during the breeding season, the Spadefoot is found only by accident. It sits in its burrow, showing only its peculiar golden eyes at the doorway. The turnip-shaped burrow is about six inches long and somewhat oblique in position. The earth on the interior is hard and smooth, packed into this condition by a continued energetic turning-about on the part of the owner of the burrow. The Spadefoot is solitary in habit, and will not tolerate the presence of a neighbour in the burrow.
This Southern Spadehoot is an attractive and alert-looking creature, very different from the uncanny, smooth-skinned Eastern Spadefoot (Scaphiopus holbrookii) and the Northwestern form Scaphiopus h. bombifrons. It is often very bright in its colouration and shows habits of jumping and walking instead of constantly burrowing; it would thus seem more adapted to terrestrial existence than are its near relatives. The adaptations for subterranean and nocturnal life are well marked, however, in the development of the inner sole tubercles and in the vertical pupil of the eye.