Most eggs per spawning for a frog or toad

The frog or toad species laying the greatest number of eggs per spawning is the cane toad Bufo marinus (aka Rhinella marina), native to South America. A single female can lay up to 35,000 eggs each time, with the strings of these eggs measuring up to 20 m long. However, because the mother then abandons them, leaving them to the mercy of the weather and predators, the mortality rate is extremely high. Nevertheless, sufficient numbers still survive for this species to have spread very swiftly across vast expanses of territory into which it has been introduced by man from its native South America, e.g. into Australia, New Guinea, various Japanese islands, the West Indies, the Philippines, Florida in the USA, so that it has become a major pest in many of these non-native locations.