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11 animals that mate for life

Feb. 12, 2010, 11:50 a.m.
Schistosoma mansoni worms

Photo: Wiki Commons

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Schistosoma mansoni worms

They may not offer the conventional image of love, but these parasitic worms are usually far more faithful than the humans they inhabit. As unromantic as it sounds, they cause the disease schistosomiasis, also known as snail fever. When they reproduce sexually within the human body, they form loyal monogamous pair bonds that typically last the entire cycle.