Western Spadefoot Toad

Fascinating facts about the Western Spadefoot Toad

• A single breeding season can see a female western spadefoot lay up to 2,000 eggs, yet each clutch only holds 10-42 eggs, meaning she may deposit dozens of tiny clusters to maximize chances. This strategy spreads risk across many puddles, a gamble that keeps the species going despite unpredictable rains.
• Tadpoles can burst from their eggs in just 15 hours and finish metamorphosis in 12-13 days, the fastest transformation known for any frog or toad. Their race against drying pools shows how evolution can squeeze life cycles to the limit of temporary water.
• Adults grow only 3.8-7.5 cm long, about the length of a matchbox, but can live around 12 years and reach breeding age at three. Their small size hides a surprisingly long lifespan, reminding us that tiny amphibians can persist for many decades.
• In Southern California the toad has lost up to 80 % of its original habitat, yet newly built mitigation pools have kept water for over 30 days in 12 of 16 sites, producing successful metamorphosis in seven pools. This illustrates how targeted engineering can rescue a species even when most natural ponds vanish.
• A 1991 study recorded that vernal pools supporting successful metamorphosis lasted an average of 83.1 days, while many artificial pools dry out sooner, highlighting the critical role of water-holding soil and liners. Understanding these numbers guides future pool designs to better match nature’s timing.

At a glance

About the Western Spadefoot Toad

The western spadefoot, Spea hammondii, is a sleek, smooth-skinned toad that roams the grasslands, scrub, chaparral and oak woodlands of central California’s valley and stretches south to San Diego and the desert fringe. Its pale-gold eyes with vertical pupils scan the night, while a green or grey dorsum, often dotted with orange-tipped tubercles, blends into the substrate. A distinctive black, wedge-shaped spade on each hind foot lets it dig quickly into moist soil, and its modest size of 3.8 to 7.5 cm makes it easy to handle; its secretions, faintly peanut-buttery, may provoke a sneeze. At night, especially during wet seasons or after summer storms, the toad emerges to feed on a banquet of insects and other invertebrates, grasshoppers, beetles, moths, spiders, ants and earthworms, while its tadpoles, once hatched from up to 2,000 eggs laid in fleeting puddles, devour algae, plankton and even conspecific larvae, sometimes turning cannibal. Remarkably, these tadpoles can metamorphose in just 12 to 13 days, the fastest known for any frog or toad, racing against the inevitable drying of their temporary pools.

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