At the beaches of Slītere NP is spawning the natterjack toad Bufo calamita – specially protected species at European level. This amphibian is living unnoticed whole year, and only in late May the natterjack toad males get together to the rut. Then their mating song can be heard quite far because of their flexible vocal sack found under the chin, which serves as a resonator. The mating call is a little similar to nightjar’s song. The natterjack toad stands out among the rest of the amphibians’ because of their ability to lay eggs into salty water. Eggs are arranged in a row, creating up to two meters long 'string'. Tadpole hatch in about a week and after three weeks turn into small toads. The process is very fast because the natterjack toads spawn in shallow pools, which dries rapidly, so time is life.
In daytime toad is hiding in the root tangle in the dip of the bank. When on the beach at times of distress it dives and hides in a pool. Toad has very few natural enemies as he releases rammish mucus, which prevents the attacker. Very negative impact on populations has driving along the beach as hidden toad is not visible from cars or motorbikes.