Sunday, April 12, 2015

Krötenwanderung



The common(true) toads emerges from hibernation in spring and there is a mass migration towards the breeding sites. Adults use the same location year after year and over 80% of males marked as juveniles have been found to return to the pond at which they were spawned. They find their way to these mainly by using olfactory and magnetic cues. Amplexus (Latin "embrace") is a type of mating behavior exhibited by some externally fertilizing species in which a male grasps a female with his front legs as part of the mating process, and at the same time or with some time delay, he fertilizes the female eggs as they are released from the body. Amplexus involves contact, a successful male stays in amplexus for several days and, as the female lays a long, double string of small black eggs, he fertilises them with his sperm. As the pair wander piggyback around the shallow edges of the pond, the gelatinous egg strings, which may contain 3000 to 6000 eggs and be 3 to 4.5 metres (10 to 15 ft) in length, get tangled in plant stalks. (https://en.wikipedia.org/wiki/Common_toad) via 500px edzerdla http://500px.com/photo/104593499