plains spadefoot has also spread into Texas and northern Mexico. Couch's spadefoot, Hurter's spadefoot, and the New Mexico spadefoot are all spread across the Southern and Southwestern U.S., with Couch's and Hurter's also reaching into Mexico. The western spadefoot is the only species found in California, mainly southern parts of the state and extending into Mexico, as well. The toads are believed to have moved into North America from South American countries due to a changing climate. They most likely moved into the U.S. as a single species, but split up as they spread across the continent and adapted to their new surroundings. The toads prefer marsh-like environments, but only enter the water to breed. They stay buried in the soil for most of the year as a mechanism to deal with changing weather. Diet American spadefoot toads have a unique diet. The adults' and tadpoles' diets vary. The adults' diet consists of invertebrates. They eat flies, crickets, caterpillars, moths, spiders, centipedes, millipedes, earthworms, and snails. The tadpoles' diet is related to its surroundings and food supply. When they are first hatched, they eat plankton. After a few days, they become carnivorous and eat animals. Tadpoles sometimes resort to cannibalism to survive. After multiple experiments, Paul Székely, Marian Tudor, and Dan Cogalniceanu concluded that tadpole development is influenced by hydroperiod, or the period in which an area is full of water. Since American spadefoot toads breed in shallow waters, they are under “constant stress from drying waters, increasing temperatures, reduced food densities, and crowding”. This stress, or simply a lack of adequate food, can increase the likelihood of cannibalism. If they do resort to cannibalism, their bodies can transform. They “develop larger heads, sharp beaks, stronger jaw muscles, and shortened intestine”. Researchers have concluded that this is an adaptive trait because it accelerates the rate of growth of the tadpoles by allowing for an increased caloric intake. Conservation efforts The eastern spadefoot was placed on the endangered list of Pennsylvania in 2005 (though also endangered in: Ohio, Connecticut, and Rhode Island), when living populations were only found in two of their known locations. One possibility for their low population size could be that breeding pools and ponds “often dry up before the tadpoles get to complete metamorphosis”(Naish, 2015) So far, conservation efforts have affected the prevention of the species habitat loss. In 2012, a couple learned that 32 acres of